2021Article de journal ER4 Auteurs : Kroeck, David M; Eriksson, Mats E; Lindskog, Anders; Munnecke, Axel; Dubois, Michel; é, Sylvie R; Servais, Thomas Morphological variability of peteinoid acritarchs from the Middle Ordovician of Öland, Sweden, and implications for acritarch classification Dans: Palynology, p. 1–15, 2021. Liens @article{Kroeck2021,
title = {Morphological variability of peteinoid acritarchs from the Middle Ordovician of Öland, Sweden, and implications for acritarch classification},
author = {David M Kroeck and Mats E Eriksson and Anders Lindskog and Axel Munnecke and Michel Dubois and Sylvie R é and Thomas Servais},
doi = {10.1080/01916122.2021.1916785},
year = {2021},
date = {2021-05-01},
journal = {Palynology},
pages = {1--15},
publisher = {Informa UK Limited},
keywords = {ER4},
pubstate = {published},
tppubtype = {article}
}
|
2021Article de journal ER4 Auteurs : Beauchamps, Gildas; Bourdelle, Franck; Dubois, Michel; Hebert, Ronan L; Ledésert, Béatrice A First characterization of the cooling of the paleo-geothermal system of Terre-de-Haut (Les Saintes archipelago, Guadeloupe): Application of fluid inclusion and chlorite thermometry Dans: Journal of Volcanology and Geothermal Research, vol. 419, p. 107370, 2021. Liens @article{Beauchamps2021,
title = {First characterization of the cooling of the paleo-geothermal system of Terre-de-Haut (Les Saintes archipelago, Guadeloupe): Application of fluid inclusion and chlorite thermometry},
author = {Gildas Beauchamps and Franck Bourdelle and Michel Dubois and Ronan L Hebert and Béatrice A Ledésert},
doi = {10.1016/j.jvolgeores.2021.107370},
year = {2021},
date = {2021-11-01},
journal = {Journal of Volcanology and Geothermal Research},
volume = {419},
pages = {107370},
publisher = {Elsevier BV},
keywords = {ER4},
pubstate = {published},
tppubtype = {article}
}
|
2021Article de journal ER4 Auteurs : Bourdelle, Franck; Dubois, Michel; Lloret, Emily; Durand, Cyril; Addad, Ahmed; Bounoua, Schéhérazade; Ventalon, Sandra; Recourt, Philippe Kaolinite-to-Chlorite Conversion from Si,Al-Rich Fluid-Origin Veins/Fe-Rich Carboniferous Shale Interaction Dans: Minerals, vol. 11, no. 8, p. 804, 2021. Liens @article{Bourdelle2021b,
title = {Kaolinite-to-Chlorite Conversion from Si,Al-Rich Fluid-Origin Veins/Fe-Rich Carboniferous Shale Interaction},
author = {Franck Bourdelle and Michel Dubois and Emily Lloret and Cyril Durand and Ahmed Addad and Schéhérazade Bounoua and Sandra Ventalon and Philippe Recourt},
doi = {10.3390/min11080804},
year = {2021},
date = {2021-07-01},
journal = {Minerals},
volume = {11},
number = {8},
pages = {804},
publisher = {MDPI AG},
keywords = {ER4},
pubstate = {published},
tppubtype = {article}
}
|
2020Conférence ER4 Auteurs : Dubois, Michel; Gauthier, Arnaud Le sel, entre formation géologique et exploitation par les hommes In : Sel et société, tome 2 : Santé - croyances -economies,, 2020, (OS). Résumé @conference{Dubois2020,
title = {Le sel, entre formation géologique et exploitation par les hommes},
author = {Michel Dubois and Arnaud Gauthier},
editor = {Prilaux (Eds) Septentrion G 201-220 Eds C. Van Cauwenberghe-Hoët A. Masse},
year = {2020},
date = {2020-01-01},
booktitle = {In : Sel et société, tome 2 : Santé - croyances -economies,},
pages = {201-220},
abstract = {Salt is a mineral substance essential to human and animal health and
is fundamental for numerous artisanal and industrial activities.
Salt production started during prehistoric times and is probably
one of the oldest extraction activity. The formation conditions of
salt (halite) and the various associated minerals, either through
natural processes or anthropogenic methods, represent a point where
archaeology, history and Earth sciences converge according to several
lines: thermodynamic modelling of the evaporation process, shoreline
evolution since Antiquity and mining industry with the consequent
sociological impacts.},
note = {OS},
keywords = {ER4},
pubstate = {published},
tppubtype = {conference}
}
Salt is a mineral substance essential to human and animal health and
is fundamental for numerous artisanal and industrial activities.
Salt production started during prehistoric times and is probably
one of the oldest extraction activity. The formation conditions of
salt (halite) and the various associated minerals, either through
natural processes or anthropogenic methods, represent a point where
archaeology, history and Earth sciences converge according to several
lines: thermodynamic modelling of the evaporation process, shoreline
evolution since Antiquity and mining industry with the consequent
sociological impacts. |
2020Conférence ER4 Auteurs : Dusséaux, Camille; Gébelin, A; Boulvais, Philippe; Ruffet, G; Dubois, Michel; Poujol, Marc; Cogné, N; Branquet, Y; Mottram, C; Barou, F; Mulch, Andreas Multidisciplinary characterisation of fluid sources in Variscan distile shear zones. Conference «Understanding earthquakes using the geological record», The Royal Society of London, 17-18 February 2020, London (Royaume-Uni), 2020, (ACTI). @conference{Dusseaux2020,
title = {Multidisciplinary characterisation of fluid sources in Variscan distile shear zones. Conference},
author = {Camille Dusséaux and A Gébelin and Philippe Boulvais and G Ruffet and Michel Dubois and Marc Poujol and N Cogné and Y Branquet and C Mottram and F Barou and Andreas Mulch},
year = {2020},
date = {2020-01-01},
booktitle = {«Understanding earthquakes using the geological record», The Royal Society of London, 17-18 February 2020, London (Royaume-Uni)},
note = {ACTI},
keywords = {ER4},
pubstate = {published},
tppubtype = {conference}
}
|
2020Article de journal ER4 Auteurs : Guillot, François; Averbuch, Olivier; Dubois, Michel; Durand, Cyril; Lanari, Pierre; Gauthier, Arnaud Zircon age of vaugnerite intrusives from the Central and Southern Vosges crystalline massifs (E France): contribution to the geodynamics of the European Variscan belt Dans: Bulletin de la Societe Géologique de France, vol. 191, no. 26, 2020, (ACLN). Résumé @article{Guillot2020,
title = {Zircon age of vaugnerite intrusives from the Central and Southern Vosges crystalline massifs (E France): contribution to the geodynamics of the European Variscan belt},
author = {François Guillot and Olivier Averbuch and Michel Dubois and Cyril Durand and Pierre Lanari and Arnaud Gauthier},
year = {2020},
date = {2020-01-01},
journal = {Bulletin de la Societe Géologique de France},
volume = {191},
number = {26},
abstract = {Datation du zircon de vaugnérites des Vosges centrales et méridionales
: contribution à la géodynamique de l’orogène varisque d’Europe.
Afin d’avancer dans la compréhension de la géodynamique des zones
de suture varisque au stade tardif de la collision (en particulier
au regard de l’évolution du système orogénique en contexte de HT),
nous nous sommes intéressés à la mise en place des vaugnérites, roches
basiques ultra-potassiques intrusives au sein des ensembles granito-gneissiques
de la croûte varisque des Vosges. Ces roches, souvent associées aux
ensembles granitiques tardi-collisionnels, sont de faible extension
mais quasiment toujours présentes au sein de ces systèmes. Elles
affleurent (1) dans les Vosges méridionales, en masses plutoniques
marginales du Granite des Ballons et (2) dans les Vosges centrales
(région de Plainfaing), en filons composites, intrusifs dans un complexe
de migmatites et de roches métamorphiques appelées granite-gneiss.
Les vaugnérites sont des roches mélanocrates à biotite et hornblende
magnésiennes (20 à 40 % vol, 64 < mg# < 78), présentant des signatures
géochimiques caractéristiques de roches ultra-potassiques mafiques
à intermédiaires, métalumineuses à légèrement peralumineuses. L’âge
U-Pb obtenu par ablation laser ICP-MS du zircon d’un gneiss à sillimanite
du granite-gneiss encaissant des vaugnérites est de 451 ± 9 Ma, révélant
un bâti pré-varisque à protolithe ordovicien supérieur. Les grains
de zircon extraits de quatre vaugnérites donnent des âges U-Pb (±
2s) de 340 ± 2,5 Ma (Ballons), 340 ± 25 Ma, 340 ± 7 Ma et 336 ± 10
Ma (Vosges centrales). Les données de datation des vaugnérites, identiques
aux incertitudes de mesure près, apparaissent donc cohérentes et
révèlent un âge assez précoce dans l’histoire tardi-collisionnelle
de la chaîne. Ces données, en accord avec les âges publiés préalablement
sur ce secteur, montrent que les vaugnérites se mettent en place
au Viséen moyen, au cours d’un événement magmatique majeur, exprimé
tant dans les séries volcano-sédimentaires (Séries OderenMarkstein)
que dans les granitoïdes ultra-potassiques des Vosges méridionales
(Ballons) et centrales (Crêtes). Les études pétrologiques récentes
sur les vaugnérites suggèrent qu’elles dérivent de la fusion partielle
d’un manteau métasomatisé et contaminé à différents degrés par des
éléments de croûte continentale fondue. Nous proposons ici que ce
« pulse » magmatique ultra-potassique d’ampleur à 340– 335 Ma soit
le signe une évolution majeure dans la dynamique de la subduction
de la lithosphère rhénohercynienne sous les Vosges centrales et méridionales.
Sur le modèle d’expériences thermomécaniques récentes simulant le
déroulement d’une collision continentale mature, il pourrait traduire
les premiers effets d’un phénomène de délamination lithosphérique
syn-collisionelle impliquant (1) une subduction continentale relayée
(2) par le sous-charriage d’une lame de croûte inférieure de la marge
continentale avalonienne et (3) l’initiation de la délamination lithosphérique
au sein du prisme orogénique supra-subduction qu’était le bloc continental
saxothüringien-moldanubien. Ce processus conduirait à la mise en
place d’un « upwelling » asthénosphérique, initialement localisé
aux zones de suture varisque et se propageant au cours de la fin
du Carbonifère vers le front sud de la chaîne à mesure de la propagation
du front de délamination à la base de la croûte},
note = {ACLN},
keywords = {ER4},
pubstate = {published},
tppubtype = {article}
}
Datation du zircon de vaugnérites des Vosges centrales et méridionales
: contribution à la géodynamique de l’orogène varisque d’Europe.
Afin d’avancer dans la compréhension de la géodynamique des zones
de suture varisque au stade tardif de la collision (en particulier
au regard de l’évolution du système orogénique en contexte de HT),
nous nous sommes intéressés à la mise en place des vaugnérites, roches
basiques ultra-potassiques intrusives au sein des ensembles granito-gneissiques
de la croûte varisque des Vosges. Ces roches, souvent associées aux
ensembles granitiques tardi-collisionnels, sont de faible extension
mais quasiment toujours présentes au sein de ces systèmes. Elles
affleurent (1) dans les Vosges méridionales, en masses plutoniques
marginales du Granite des Ballons et (2) dans les Vosges centrales
(région de Plainfaing), en filons composites, intrusifs dans un complexe
de migmatites et de roches métamorphiques appelées granite-gneiss.
Les vaugnérites sont des roches mélanocrates à biotite et hornblende
magnésiennes (20 à 40 % vol, 64 < mg# < 78), présentant des signatures
géochimiques caractéristiques de roches ultra-potassiques mafiques
à intermédiaires, métalumineuses à légèrement peralumineuses. L’âge
U-Pb obtenu par ablation laser ICP-MS du zircon d’un gneiss à sillimanite
du granite-gneiss encaissant des vaugnérites est de 451 ± 9 Ma, révélant
un bâti pré-varisque à protolithe ordovicien supérieur. Les grains
de zircon extraits de quatre vaugnérites donnent des âges U-Pb (±
2s) de 340 ± 2,5 Ma (Ballons), 340 ± 25 Ma, 340 ± 7 Ma et 336 ± 10
Ma (Vosges centrales). Les données de datation des vaugnérites, identiques
aux incertitudes de mesure près, apparaissent donc cohérentes et
révèlent un âge assez précoce dans l’histoire tardi-collisionnelle
de la chaîne. Ces données, en accord avec les âges publiés préalablement
sur ce secteur, montrent que les vaugnérites se mettent en place
au Viséen moyen, au cours d’un événement magmatique majeur, exprimé
tant dans les séries volcano-sédimentaires (Séries OderenMarkstein)
que dans les granitoïdes ultra-potassiques des Vosges méridionales
(Ballons) et centrales (Crêtes). Les études pétrologiques récentes
sur les vaugnérites suggèrent qu’elles dérivent de la fusion partielle
d’un manteau métasomatisé et contaminé à différents degrés par des
éléments de croûte continentale fondue. Nous proposons ici que ce
« pulse » magmatique ultra-potassique d’ampleur à 340– 335 Ma soit
le signe une évolution majeure dans la dynamique de la subduction
de la lithosphère rhénohercynienne sous les Vosges centrales et méridionales.
Sur le modèle d’expériences thermomécaniques récentes simulant le
déroulement d’une collision continentale mature, il pourrait traduire
les premiers effets d’un phénomène de délamination lithosphérique
syn-collisionelle impliquant (1) une subduction continentale relayée
(2) par le sous-charriage d’une lame de croûte inférieure de la marge
continentale avalonienne et (3) l’initiation de la délamination lithosphérique
au sein du prisme orogénique supra-subduction qu’était le bloc continental
saxothüringien-moldanubien. Ce processus conduirait à la mise en
place d’un « upwelling » asthénosphérique, initialement localisé
aux zones de suture varisque et se propageant au cours de la fin
du Carbonifère vers le front sud de la chaîne à mesure de la propagation
du front de délamination à la base de la croûte |
2019Conférence ER4 Auteurs : Dubois, Michel; Armynot-du-Châtelet, Eric; Hadot, V; Toullec, R; Ventalon, Sandra Reconstitution de sculptures fragmentées par approches multitechniques (micropaléontologie, pétrographie et minéralogie) : exemple du gisant de Jeanne d’Ecaussinnes du Musée de Valenciennes Rencontres Interdisciplinaires et Interprofessionnelles Géosciences - Archéologie, 17-18 juin 2019, Strasbourg, 2019, (AFF). @conference{Dubois2019,
title = {Reconstitution de sculptures fragmentées par approches multitechniques (micropaléontologie, pétrographie et minéralogie) : exemple du gisant de Jeanne d’Ecaussinnes du Musée de Valenciennes},
author = {Michel Dubois and Eric Armynot-du-Châtelet and V Hadot and R Toullec and Sandra Ventalon},
year = {2019},
date = {2019-01-01},
booktitle = {Rencontres Interdisciplinaires et Interprofessionnelles Géosciences - Archéologie, 17-18 juin 2019, Strasbourg},
pages = {15-16},
note = {AFF},
keywords = {ER4},
pubstate = {published},
tppubtype = {conference}
}
|
2019Conférence ER4 Auteurs : Dusséaux, Camille; Gebelin, Aude; Boulvais, Philippe; Gardien, Véronique; Dubois, Michel; Ruffet, G; Poujol, Marc; Branquet, Y; Grimes, S; Mulch, Andreas Characterization of meteoric water infiltration in Variscan shear zones Goldschmidt Conference, 18-13 August 2019, Barcelone (Espagne), 2019, (COM). @conference{Dusseaux2019,
title = {Characterization of meteoric water infiltration in Variscan shear zones},
author = {Camille Dusséaux and Aude Gebelin and Philippe Boulvais and Véronique Gardien and Michel Dubois and G Ruffet and Marc Poujol and Y Branquet and S Grimes and Andreas Mulch},
year = {2019},
date = {2019-01-01},
booktitle = {Goldschmidt Conference, 18-13 August 2019, Barcelone (Espagne)},
note = {COM},
keywords = {ER4},
pubstate = {published},
tppubtype = {conference}
}
|
2019Conférence ER4 Auteurs : Gauthier, Arnaud; Dubois, Michel; Cochard, L Apport de la minéralogie et de la géochimie à l’étude de la compréhension des processus archéométallurgiques. Cas des ferriers de la forêt de Moulière Rencontres Interdisciplinaires et Interprofessionnelles Géosciences - Archéologie, 17 -18 juin 2019, Strasbourg, 2019, (AFF). @conference{Gauthier2019,
title = {Apport de la minéralogie et de la géochimie à l’étude de la compréhension des processus archéométallurgiques. Cas des ferriers de la forêt de Moulière},
author = {Arnaud Gauthier and Michel Dubois and L Cochard},
year = {2019},
date = {2019-01-01},
booktitle = {Rencontres Interdisciplinaires et Interprofessionnelles Géosciences - Archéologie, 17 -18 juin 2019, Strasbourg},
pages = {29-30},
note = {AFF},
keywords = {ER4},
pubstate = {published},
tppubtype = {conference}
}
|
2018Article de journal ER4 Auteurs : Crognier, Nemo; Hoareau, Guilhem; Aubourg, Charles; Dubois, Michel; Lacroix, Brice; Branellec, Mathieu; Callot, Jean-Paul; Vennemann, Torsten Syn-orogenic fluid flow in the Jaca basin (South Pyrenean Fold and Thrust Belt) from fracture and vein analyses Dans: Basin Research, p. Accepted manuscript online, 2018, (ACL). Résumé @article{Crognier2018,
title = {Syn-orogenic fluid flow in the Jaca basin (South Pyrenean Fold and Thrust Belt) from fracture and vein analyses},
author = {Nemo Crognier and Guilhem Hoareau and Charles Aubourg and Michel Dubois and Brice Lacroix and Mathieu Branellec and Jean-Paul Callot and Torsten Vennemann},
year = {2018},
date = {2018-01-01},
journal = {Basin Research},
pages = {Accepted manuscript online},
abstract = {This study aims at understanding the origin and nature of syn-orogenic fluid flow in the Jaca basin from the South Pyrenean fold and thrust-belt, as recorded in calcite and quartz veins of the Sierras Interiores (Spain) and the turbiditic basin, which cover upper Cretaceous t Late Eocene syntectonic deposits. The fracture network consists of a classical pattern of transverse and longitudinal fractures related to Layer Parallel Shortening (LPS) and folding respectively. Veins filled equally about the third of fractures in the carbonate shelf and turbidites. Carbon and oxygen isotopes of calcite veins mostly indicate precipitation from isotopically buffered water, consistent with high water-rock interaction. In the Sierras Interiores, petrographical observations and fluid inclusion microthermometry are consistent with two distinct stages of precipitation. The first stage is characterized by relatively low Th and low salinities (155-205° C and 0.5-3.2 wt% eq. NaCl). The second stage, which was characterized both by the formation of mode-I joints and by mode-I reactivation of preexisting veins, shows higher Th and salinities (215-270°C and 2.2-5.7 wt% eq. NaCl). Waters recorded in the second stage are interpreted to have interacted with underlying Triassic evaporites and flowed along major thrusts before vein precipitation, which are locally in thermal disequilibrium with host-rocks. We suggest the transition from a
rather closed hydrological system during the first stage of vein formation, interpreted to have occurred during Eaux-chaudes thrusting (upper Lutetian-Bartonian), to a more open hydrological system during the second stage, which likely occurred during Gavarnie thrusting (Priabonian-early Rupelian). Finally, we also document the migration in space and time of hydrothermal pulses along the South Pyrenean Foreland Basin, related to the westward propagation of major thrusts during the Pyrenean orogeny.},
note = {ACL},
keywords = {ER4},
pubstate = {published},
tppubtype = {article}
}
This study aims at understanding the origin and nature of syn-orogenic fluid flow in the Jaca basin from the South Pyrenean fold and thrust-belt, as recorded in calcite and quartz veins of the Sierras Interiores (Spain) and the turbiditic basin, which cover upper Cretaceous t Late Eocene syntectonic deposits. The fracture network consists of a classical pattern of transverse and longitudinal fractures related to Layer Parallel Shortening (LPS) and folding respectively. Veins filled equally about the third of fractures in the carbonate shelf and turbidites. Carbon and oxygen isotopes of calcite veins mostly indicate precipitation from isotopically buffered water, consistent with high water-rock interaction. In the Sierras Interiores, petrographical observations and fluid inclusion microthermometry are consistent with two distinct stages of precipitation. The first stage is characterized by relatively low Th and low salinities (155-205° C and 0.5-3.2 wt% eq. NaCl). The second stage, which was characterized both by the formation of mode-I joints and by mode-I reactivation of preexisting veins, shows higher Th and salinities (215-270°C and 2.2-5.7 wt% eq. NaCl). Waters recorded in the second stage are interpreted to have interacted with underlying Triassic evaporites and flowed along major thrusts before vein precipitation, which are locally in thermal disequilibrium with host-rocks. We suggest the transition from a
rather closed hydrological system during the first stage of vein formation, interpreted to have occurred during Eaux-chaudes thrusting (upper Lutetian-Bartonian), to a more open hydrological system during the second stage, which likely occurred during Gavarnie thrusting (Priabonian-early Rupelian). Finally, we also document the migration in space and time of hydrothermal pulses along the South Pyrenean Foreland Basin, related to the westward propagation of major thrusts during the Pyrenean orogeny. |
2018Conférence ER4 Auteurs : Althoff, Fernando; Dubois, Michel Evolution de la shear zone d'Itajaí-Perimbó, sud du Brésil : contraintes apportées par les inclusions fluides 26ème Réunion des Sciences de la Terre, 22-26 octobre 2018, Lille, 2018, (COM). @conference{Althoff2018,
title = {Evolution de la shear zone d'Itajaí-Perimbó, sud du Brésil : contraintes apportées par les inclusions fluides},
author = {Fernando Althoff and Michel Dubois},
year = {2018},
date = {2018-01-01},
booktitle = {26ème Réunion des Sciences de la Terre, 22-26 octobre 2018, Lille},
pages = {475},
note = {COM},
keywords = {ER4},
pubstate = {published},
tppubtype = {conference}
}
|
2018Conférence ER4 Auteurs : Barras, J; Dubois, Michel; Armynot-du-Châtelet, Eric; Recourt, P Patrimoine pariétal récent de carrières péri-urbaines (commune de Lezennes, périphérie de Lille) : au croisement de l'histoire géologique et de l'histoire humaine, 26ème Réunion des Sciences de la Terre, 22-26 octobre 2018, Lille, 2018, (COM). @conference{Barras2018,
title = {Patrimoine pariétal récent de carrières péri-urbaines (commune de Lezennes, périphérie de Lille) : au croisement de l'histoire géologique et de l'histoire humaine,},
author = {J Barras and Michel Dubois and Eric Armynot-du-Châtelet and P Recourt},
year = {2018},
date = {2018-01-01},
booktitle = {26ème Réunion des Sciences de la Terre, 22-26 octobre 2018, Lille},
pages = {530},
note = {COM},
keywords = {ER4},
pubstate = {published},
tppubtype = {conference}
}
|
2018Conférence ER4 Auteurs : Beauchamps, G; Ledésert, Béatrice; Hébert, R; Bourdelle, Franck; Dubois, Michel Characterization of an exhumed high temperature paleo-geothermal reservoir by clay minerals and secondary phases identifications in Terre-de-Haut island (Les Saintes archipelago, Guadeloupe) 26ème Réunion des Sciences de la Terre, 22-26 octobre 2018, Lille, 2018, (COM). @conference{Beauchamps2018,
title = {Characterization of an exhumed high temperature paleo-geothermal reservoir by clay minerals and secondary phases identifications in Terre-de-Haut island (Les Saintes archipelago, Guadeloupe)},
author = {G Beauchamps and Béatrice Ledésert and R Hébert and Franck Bourdelle and Michel Dubois},
year = {2018},
date = {2018-01-01},
booktitle = {26ème Réunion des Sciences de la Terre, 22-26 octobre 2018, Lille},
pages = {660},
note = {COM},
keywords = {ER4},
pubstate = {published},
tppubtype = {conference}
}
|
2018Conférence ER4 Auteurs : Armynot-du-Chatelet, Eric; Dubois, Michel; Hadot, V; Toullec, T; Ventalon, Sandra; Recourt, P Approche multi-technique en archéologie (micropaléontologie, pétrographie et minéralogie) : exemple de la reconstitution d'un gisant fragmenté du Musée de Valenciennes 26ème Réunion des Sciences de la Terre, 22-26 octobre 2018, Lille, 2018, (AFF). @conference{Chatelet2018,
title = {Approche multi-technique en archéologie (micropaléontologie, pétrographie et minéralogie) : exemple de la reconstitution d'un gisant fragmenté du Musée de Valenciennes},
author = {Eric Armynot-du-Chatelet and Michel Dubois and V Hadot and T Toullec and Sandra Ventalon and P Recourt},
year = {2018},
date = {2018-01-01},
booktitle = {26ème Réunion des Sciences de la Terre, 22-26 octobre 2018, Lille},
pages = {485},
note = {AFF},
keywords = {ER4},
pubstate = {published},
tppubtype = {conference}
}
|
2018Conférence ER4 Auteurs : Cuvelier, J; Dubois, Michel; Maiga, M H De Brest à Lille ; la kersantite, une roche bretonne collectée par Charles Barrois 26ème Réunion des Sciences de la Terre, 22-26 octobre 2018, Lille, 2018, (AFF). @conference{Cuvelier2018,
title = {De Brest à Lille ; la kersantite, une roche bretonne collectée par Charles Barrois},
author = {J Cuvelier and Michel Dubois and M H Maiga},
year = {2018},
date = {2018-01-01},
booktitle = {26ème Réunion des Sciences de la Terre, 22-26 octobre 2018, Lille},
pages = {532},
note = {AFF},
keywords = {ER4},
pubstate = {published},
tppubtype = {conference}
}
|
2018Conférence ER4 Auteurs : Dusséaux, Camille; Gébebin, A; Boulvais, Philippe; Gardien, Véronique; Dubois, Michel; Grimes, S; Mulch, Andreas Meteoric water-rock interaction in Variscan ductile shear zones Tectonics Studies Group (TSG) and Metamorphic Studies Group (MSG), University of Plymouth, 3-5 January 2018, 2018, (AFF). @conference{Dusseaux2018,
title = {Meteoric water-rock interaction in Variscan ductile shear zones},
author = {Camille Dusséaux and A Gébebin and Philippe Boulvais and Véronique Gardien and Michel Dubois and S Grimes and Andreas Mulch},
year = {2018},
date = {2018-01-01},
booktitle = {Tectonics Studies Group (TSG) and Metamorphic Studies Group (MSG), University of Plymouth, 3-5 January 2018},
note = {AFF},
keywords = {ER4},
pubstate = {published},
tppubtype = {conference}
}
|
2018Conférence ER4 Auteurs : Dusséaux, Camille; Gébelin, A; Boulvais, Philippe; Dubois, Michel; Ruffet, G; Poujol, Marc; Branquet, Y; F., Barou; Mulch, Andreas Late-Carboniferous infiltration of meteoric water in Variscan shear zones 26ème Réunion des Sciences de la Terre, 22-26 octobre 2018, Lille, 2018, (COM). @conference{Dusseaux2018a,
title = {Late-Carboniferous infiltration of meteoric water in Variscan shear zones},
author = {Camille Dusséaux and A Gébelin and Philippe Boulvais and Michel Dubois and G Ruffet and Marc Poujol and Y Branquet and Barou F. and Andreas Mulch},
year = {2018},
date = {2018-01-01},
booktitle = {26ème Réunion des Sciences de la Terre, 22-26 octobre 2018, Lille},
pages = {530},
note = {COM},
keywords = {ER4},
pubstate = {published},
tppubtype = {conference}
}
|
2018Conférence ER4 Auteurs : Fouad, Amin; Le-Coustumer, Philippe; Bernard, M; Gauthier, Arnaud; Dubois, Michel; Raux, J -J; Charlier, G Nouvelle méthode d'élaboration de sections polies et lames minces de matériaux cimentaires frais : préservation des caractéristiques microstructurales 26ème Réunion des Sciences de la Terre, 22-26 octobre 2018, Lille, 2018, (AFF). @conference{Fouad2018a,
title = {Nouvelle méthode d'élaboration de sections polies et lames minces de matériaux cimentaires frais : préservation des caractéristiques microstructurales},
author = {Amin Fouad and Philippe Le-Coustumer and M Bernard and Arnaud Gauthier and Michel Dubois and J -J Raux and G Charlier},
year = {2018},
date = {2018-01-01},
booktitle = {26ème Réunion des Sciences de la Terre, 22-26 octobre 2018, Lille},
pages = {647},
note = {AFF},
keywords = {ER4},
pubstate = {published},
tppubtype = {conference}
}
|
2018Conférence ER4 Auteurs : Fouad, Amin; Le-Coustumer, Philippe; Raux, J -J; Charlier, G; Gauthier, Arnaud; Dubois, Michel Nouvelle méthode de préparation par rodage de sections polies de matériaux minéraux sensibles à l'eau 26ème Réunion des Sciences de la Terre, 22-26 octobre 2018, Lille, 2018, (AFF). @conference{Fouad2018b,
title = {Nouvelle méthode de préparation par rodage de sections polies de matériaux minéraux sensibles à l'eau},
author = {Amin Fouad and Philippe Le-Coustumer and J -J Raux and G Charlier and Arnaud Gauthier and Michel Dubois},
year = {2018},
date = {2018-01-01},
booktitle = {26ème Réunion des Sciences de la Terre, 22-26 octobre 2018, Lille},
pages = {645},
note = {AFF},
keywords = {ER4},
pubstate = {published},
tppubtype = {conference}
}
|
2018Conférence ER4 Auteurs : Gauthier, Arnaud; Masse, J; Motelica-Heino, Mikael; Dubois, Charlotte; Dubois, Michel Apport de l'agriculture urbaine dans une démarche de requalification de friches contaminées en jardin collectif : évaluation des sols et impacts environnementaux associés 26ème Réunion des Sciences de la Terre, 22-26 octobre 2018, Lille, 2018, (COM). @conference{Gauthier2018,
title = {Apport de l'agriculture urbaine dans une démarche de requalification de friches contaminées en jardin collectif : évaluation des sols et impacts environnementaux associés},
author = {Arnaud Gauthier and J Masse and Mikael Motelica-Heino and Charlotte Dubois and Michel Dubois},
year = {2018},
date = {2018-01-01},
booktitle = {26ème Réunion des Sciences de la Terre, 22-26 octobre 2018, Lille},
pages = {342},
note = {COM},
keywords = {ER4},
pubstate = {published},
tppubtype = {conference}
}
|
2018Conférence ER4 Auteurs : Guillot, F; Averbuch, Olivier; Dubois, Michel; Durand, Cyril; Lanari, Pierre; Delangle, C; Gauthier, Arnaud Vaugnérites des Vosges : datations U-Pb sur zircon par LA-ICP-MS et hypothèses génétiques 26ème Réunion des Sciences de la Terre, 22-26 octobre 2018, Lille, 2018, (COM). @conference{Guillot2018,
title = {Vaugnérites des Vosges : datations U-Pb sur zircon par LA-ICP-MS et hypothèses génétiques},
author = {F Guillot and Olivier Averbuch and Michel Dubois and Cyril Durand and Pierre Lanari and C Delangle and Arnaud Gauthier},
year = {2018},
date = {2018-01-01},
booktitle = {26ème Réunion des Sciences de la Terre, 22-26 octobre 2018, Lille},
pages = {530},
note = {COM},
keywords = {ER4},
pubstate = {published},
tppubtype = {conference}
}
|
2018Conférence ER4 Auteurs : Lavina, Pierre; Kieffer, M; Nasraoui, Mohamed; Dubois, Michel; Labrit, A; Mayoux, M Le Géosite de l'Améthyste d'Auvergne, premier gisement d'Europe : inventaires, études géologiques et valorisation du patrimoine géologique et minier pour l'art lapidaire et la bijouterie Colloque de restitution de l’Inventaire National du Patrimoine Géologique (INPG), 15-17 octobre 2018, Chambéry, 2018, (AFF). @conference{Lavina2018,
title = {Le Géosite de l'Améthyste d'Auvergne, premier gisement d'Europe : inventaires, études géologiques et valorisation du patrimoine géologique et minier pour l'art lapidaire et la bijouterie},
author = {Pierre Lavina and M Kieffer and Mohamed Nasraoui and Michel Dubois and A Labrit and M Mayoux},
year = {2018},
date = {2018-01-01},
booktitle = {Colloque de restitution de l’Inventaire National du Patrimoine Géologique (INPG), 15-17 octobre 2018, Chambéry},
note = {AFF},
keywords = {ER4},
pubstate = {published},
tppubtype = {conference}
}
|
2018Conférence ER4 Auteurs : Nasraoui, Mohamed; Lavina, Pierre; Dubois, Michel; Lutz, P La Rodde an old mine of Antimony (French Central Massif): between re-evaluation of the mining potential and environmental footprints 26ème Réunion des Sciences de la Terre, 22-26 octobre 2018, Lille, 2018, (AFF). @conference{Nasraoui2018,
title = {La Rodde an old mine of Antimony (French Central Massif): between re-evaluation of the mining potential and environmental footprints},
author = {Mohamed Nasraoui and Pierre Lavina and Michel Dubois and P Lutz},
year = {2018},
date = {2018-01-01},
booktitle = {26ème Réunion des Sciences de la Terre, 22-26 octobre 2018, Lille},
pages = {684},
note = {AFF},
keywords = {ER4},
pubstate = {published},
tppubtype = {conference}
}
|
2018Conférence ER4 Auteurs : Ould-Moctar, Didi; Moukadiri, Ali; Boushaba, Abdellah; Ould-Mohamed-Lemine, Sid’Ahmed; Dubois, Michel Petrographical and geochemical characteristics of the Mauritanides Belts’ Birbirites 1st Springer Conference of the Arabian Journal of Geosciences (CAJG-1), 12-15 November 2018, Hammamet (Tunisia), 2018, (ACTI). Résumé @conference{Ould-Moctar2018,
title = {Petrographical and geochemical characteristics of the Mauritanides Belts’ Birbirites},
author = {Didi Ould-Moctar and Ali Moukadiri and Abdellah Boushaba and Sid’Ahmed Ould-Mohamed-Lemine and Michel Dubois},
year = {2018},
date = {2018-01-01},
booktitle = {1st Springer Conference of the Arabian Journal of Geosciences (CAJG-1), 12-15 November 2018, Hammamet (Tunisia)},
pages = {55-57},
abstract = {The Gouérarate region represents the most important area of birbirites’
outcrops, sited in the Mauritanides Belts. In this paper, the petrological
description of such facies is highlighted. The Gouérarate Birbirites
are mainly composed of silica (chalcedony and microquartz) and talc,
geochemically characterized with high SiO2 level (up to 80%). They
are derived from a highly refractory peridotite and serpentinite,
which correspond to former dunite, harzburgite and serpentinite.
The birbirites are mainly formed of ultramafic rocks’ weathering,
which has resulted in the concentration of SiO2 and the transformation
of olivine, pyroxene and serpentines into chalcedony, quartz and
talc.},
note = {ACTI},
keywords = {ER4},
pubstate = {published},
tppubtype = {conference}
}
The Gouérarate region represents the most important area of birbirites’
outcrops, sited in the Mauritanides Belts. In this paper, the petrological
description of such facies is highlighted. The Gouérarate Birbirites
are mainly composed of silica (chalcedony and microquartz) and talc,
geochemically characterized with high SiO2 level (up to 80%). They
are derived from a highly refractory peridotite and serpentinite,
which correspond to former dunite, harzburgite and serpentinite.
The birbirites are mainly formed of ultramafic rocks’ weathering,
which has resulted in the concentration of SiO2 and the transformation
of olivine, pyroxene and serpentines into chalcedony, quartz and
talc. |
2018Conférence ER4 Auteurs : Ramadan, Ghanem; Dubois, Michel; Gauthier, Arnaud; Cheppe, Gaetan Impact de l’eau sue la stabilité des carrières souterraines : corrélation avec les épisodes météorologiques de surface 26ème Réunion des Sciences de la Terre, 22-26 octobre 2018, Lille, 2018, (AFF). @conference{Ramadan2018,
title = {Impact de l’eau sue la stabilité des carrières souterraines : corrélation avec les épisodes météorologiques de surface},
author = {Ghanem Ramadan and Michel Dubois and Arnaud Gauthier and Gaetan Cheppe},
year = {2018},
date = {2018-01-01},
booktitle = {26ème Réunion des Sciences de la Terre, 22-26 octobre 2018, Lille},
pages = {687},
note = {AFF},
keywords = {ER4},
pubstate = {published},
tppubtype = {conference}
}
|
2018Article de journal ER4 Auteurs : Tuduri, Johann; Chauvet, Alain; Barbanson, Luc; Bourdier, Jean-Louis; Labriki, Mohamed; Ennaciri, Aomar; Badra, Lakhlifi; Dubois, Michel; Ennaciri-Leloix, Christelle; Sizaret, Stanislas; Maacha, Lhou The Jbel Saghro Au(-Ag, Cu) and Ag-Hg Metallogenetic Province: Product of a Long-Lived Ediacaran Tectono-Magmatic Evolution in the Moroccan Anti-Atlas Dans: Minerals, vol. 8, no. 12, p. 48, 2018, (ACL). Résumé @article{Tuduri2018,
title = {The Jbel Saghro Au(-Ag, Cu) and Ag-Hg Metallogenetic Province: Product of a Long-Lived Ediacaran Tectono-Magmatic Evolution in the Moroccan Anti-Atlas},
author = {Johann Tuduri and Alain Chauvet and Luc Barbanson and Jean-Louis Bourdier and Mohamed Labriki and Aomar Ennaciri and Lakhlifi Badra and Michel Dubois and Christelle Ennaciri-Leloix and Stanislas Sizaret and Lhou Maacha},
year = {2018},
date = {2018-01-01},
journal = {Minerals},
volume = {8},
number = {12},
pages = {48},
abstract = {The Jbel Saghro is interpreted as part of a long-lived silicic large
igneous province. The area comprises two lithostructural complexes.
The Lower Complex consists of folded metagreywackes and N070-090
degrees E dextral shear zones, which roughly results from a NW-SE
to NNW-SSE shortening direction related to a D-1 transpressive tectonic
stage. D-1 is also combined with syntectonic plutons emplaced between
ca. 615 and 575 Ma. The Upper Complex is defined by ash-flow caldera
emplacements, thick and widespread ignimbrites, lavas and volcaniclastic
sedimentary rocks with related intrusives that were emplaced in three
main magmatic flare ups at ca. 575, 565 and 555 Ma. It lies unconformably
on the Lower Complex units and was affected by a D-2 trantensive
tectonic stage. Between 550 and 540 Ma, the magmatic activity became
slightly alkaline and of lower extent. Ore deposits show specific
features, but remain controlled by the same structural setting: a
NNW-SSE shortening direction related to both D-1 and D-2 stages.
Porphyry Au(-Cu-Mo) and intrusion-related gold deposits were emplaced
in an earlier stage between 580 and 565 Ma. Intermediate sulfidation
epithermal deposits may have been emplaced during lull periods after
the second and (or) the third flare-ups (560-550 Ma). Low sulfidation
epithermal deposits were emplaced late during the felsic alkaline
magmatic stage (550-520 Ma). The D-2 stage, therefore, provided extensional
structures that enabled fluid circulations and magmatic-hydrothermal
ore forming processes.},
note = {ACL},
keywords = {ER4},
pubstate = {published},
tppubtype = {article}
}
The Jbel Saghro is interpreted as part of a long-lived silicic large
igneous province. The area comprises two lithostructural complexes.
The Lower Complex consists of folded metagreywackes and N070-090
degrees E dextral shear zones, which roughly results from a NW-SE
to NNW-SSE shortening direction related to a D-1 transpressive tectonic
stage. D-1 is also combined with syntectonic plutons emplaced between
ca. 615 and 575 Ma. The Upper Complex is defined by ash-flow caldera
emplacements, thick and widespread ignimbrites, lavas and volcaniclastic
sedimentary rocks with related intrusives that were emplaced in three
main magmatic flare ups at ca. 575, 565 and 555 Ma. It lies unconformably
on the Lower Complex units and was affected by a D-2 trantensive
tectonic stage. Between 550 and 540 Ma, the magmatic activity became
slightly alkaline and of lower extent. Ore deposits show specific
features, but remain controlled by the same structural setting: a
NNW-SSE shortening direction related to both D-1 and D-2 stages.
Porphyry Au(-Cu-Mo) and intrusion-related gold deposits were emplaced
in an earlier stage between 580 and 565 Ma. Intermediate sulfidation
epithermal deposits may have been emplaced during lull periods after
the second and (or) the third flare-ups (560-550 Ma). Low sulfidation
epithermal deposits were emplaced late during the felsic alkaline
magmatic stage (550-520 Ma). The D-2 stage, therefore, provided extensional
structures that enabled fluid circulations and magmatic-hydrothermal
ore forming processes. |
2018Article de journal ER4 Auteurs : Tuduri, Johann; Chauvet, Alain; Barbanson, Luc; Labriki, Mohamed; Dubois, Michel; Trapy, Pierre-Henri; Lahfid, Abdeltif; Poujol, Marc; Melleton, Jérémie; Badra, Lakhlifi; Ennaciri, Aomar; Maacha, Lhou Structural control, magmatic-hydrothermal evolution and formation of hornfels-hosted, intrusion-related gold deposits: Insight from the Thaghassa deposit in Eastern Anti-Atlas, Morocco Dans: Ore Geology Reviews, vol. 97, p. 171-198, 2018, (ACL). Résumé @article{Tuduri2018a,
title = {Structural control, magmatic-hydrothermal evolution and formation of hornfels-hosted, intrusion-related gold deposits: Insight from the Thaghassa deposit in Eastern Anti-Atlas, Morocco},
author = {Johann Tuduri and Alain Chauvet and Luc Barbanson and Mohamed Labriki and Michel Dubois and Pierre-Henri Trapy and Abdeltif Lahfid and Marc Poujol and Jérémie Melleton and Lakhlifi Badra and Aomar Ennaciri and Lhou Maacha},
year = {2018},
date = {2018-01-01},
journal = {Ore Geology Reviews},
volume = {97},
pages = {171-198},
abstract = {In the Moroccan Eastern Anti-Atlas, the Thaghassa intrusion-related
gold deposit is hosted in hornfelsedfelsed metasedimentary rocks
that lie adjacent to the Ikniwn granodiorite. Field studies reveal
three tectono-magmatic stages controlling the formation of the deposit,
i) The first stage refers to the top-to-the-south asymmetry and the
syn-kinematic Ikniwn pluton emplacement controlled by a compressional
or transpressional strain regime, ii) The second stage is characterized,
from older to younger and further away from the intrusion, by: metatexite
with leucocratic stromatic bands, aplo-pegmatite sills, intermediate
veinlets composed of quartz, K-feldspar and muscovite, and then gold-bearing
striped foliation-veins. All these features are assumed to have been
emplaced during a large-scale ENE-WSW dextral shearing process that
results from an ESE-WNW shortening direction during transtensive
tectonics. We suggest that the progressive and continuous shearing
was initiated since the aplo-pegmatite stage and achieved during
the hydrothermal phase. The existence of intermediate veins characterized
by quartz-rich core and apatite-muscovite-feldspar-rich rims demonstrates
the progressive evolution from the magmatic to the hydrothermal stage
and evidence for the persistence of the magmatic character, at least
until the onset of the hydrothermal p. cess, iii) The late stage
developed large volcanic dyke swarm and brittle faulting. Zircon
U-Pb LA-ICP-MS dating yields a Concordia age of +/- 63.5 +/- 6.3
Ma for the Ikniwn granodiorite intrusion. The fluid inclusions data
besides the mineral thermometry indicate that two main types of fluids
can been highlighted: i) a hot aquo-carbonic (H2O-NaCl-CO2) fluid
with N-2 and CH4, evolving from vapour-rich N-2 and CH4 inclusions
for the magmatic stage (similar to 550 degrees C)( )to CH4-CO2 biphased
inclusions for the ongoing hydrothermal stage (similar to 450-300
degrees C) and ii) an always secondary low T (similar to 200 degrees
C) saline aqueous type (probably NaCl) free from volatiles, with
very variable salinity. Eventually, we highlight that in the hornfels-hosted
IRG deposits, fluid sources may originate from both magmatic processes
and devolatization of the metamorphic host rocks.},
note = {ACL},
keywords = {ER4},
pubstate = {published},
tppubtype = {article}
}
In the Moroccan Eastern Anti-Atlas, the Thaghassa intrusion-related
gold deposit is hosted in hornfelsedfelsed metasedimentary rocks
that lie adjacent to the Ikniwn granodiorite. Field studies reveal
three tectono-magmatic stages controlling the formation of the deposit,
i) The first stage refers to the top-to-the-south asymmetry and the
syn-kinematic Ikniwn pluton emplacement controlled by a compressional
or transpressional strain regime, ii) The second stage is characterized,
from older to younger and further away from the intrusion, by: metatexite
with leucocratic stromatic bands, aplo-pegmatite sills, intermediate
veinlets composed of quartz, K-feldspar and muscovite, and then gold-bearing
striped foliation-veins. All these features are assumed to have been
emplaced during a large-scale ENE-WSW dextral shearing process that
results from an ESE-WNW shortening direction during transtensive
tectonics. We suggest that the progressive and continuous shearing
was initiated since the aplo-pegmatite stage and achieved during
the hydrothermal phase. The existence of intermediate veins characterized
by quartz-rich core and apatite-muscovite-feldspar-rich rims demonstrates
the progressive evolution from the magmatic to the hydrothermal stage
and evidence for the persistence of the magmatic character, at least
until the onset of the hydrothermal p. cess, iii) The late stage
developed large volcanic dyke swarm and brittle faulting. Zircon
U-Pb LA-ICP-MS dating yields a Concordia age of +/- 63.5 +/- 6.3
Ma for the Ikniwn granodiorite intrusion. The fluid inclusions data
besides the mineral thermometry indicate that two main types of fluids
can been highlighted: i) a hot aquo-carbonic (H2O-NaCl-CO2) fluid
with N-2 and CH4, evolving from vapour-rich N-2 and CH4 inclusions
for the magmatic stage (similar to 550 degrees C)( )to CH4-CO2 biphased
inclusions for the ongoing hydrothermal stage (similar to 450-300
degrees C) and ii) an always secondary low T (similar to 200 degrees
C) saline aqueous type (probably NaCl) free from volatiles, with
very variable salinity. Eventually, we highlight that in the hornfels-hosted
IRG deposits, fluid sources may originate from both magmatic processes
and devolatization of the metamorphic host rocks. |
2017Conférence ER4 Auteurs : Althoff, F; Dubois, Michel; Castro, N Fluid inclusions constraints on the origin of Ribeirão da Prata lead and zinc ore deposits (southern Brazil) XXIVth European Current Research On Fluid Inclusions (ECROFI), 25-29 Juin, Nancy, 2017, (ACTI). Résumé @conference{Althoff2017,
title = {Fluid inclusions constraints on the origin of Ribeirão da Prata lead and zinc ore deposits (southern Brazil)},
author = {F Althoff and Michel Dubois and N Castro},
year = {2017},
date = {2017-01-01},
booktitle = {XXIVth European Current Research On Fluid Inclusions (ECROFI), 25-29 Juin, Nancy},
abstract = {The Itajaí-Perimbó shear zone (IPSZ), in southern Brazil, is the northern boundary of the Brasiliano/ Pan-African Dom Feliciano Belt, whose evolution is related to the West Gondwana collage. This NE-SW shear zone is the limit between the Itajaí basin, at NW, and the Brusque group (part of Dom Feliciano Belt), at SE. The Itajaí basin is a Neoproterozoic foreland basin, with sedimentation occurring between 600 to 560 Ma. Brusque group is composed of schists and marbles with granitoids, that evolved from 900 to 540 Ma (Basei et al., 2011ab). The IPSZ hosts a lead and zinc (copper and silver) ore deposit at the Ribeirão da Prata mine. Galena, sphalerite, chalcopyrite and pyrite are the primary ore minerals. Covellite, goethite, malachite azurite (cerussite and pyromorphite) represent the secondary ore paragenesis (Biondi et al., 1992). The formation of this deposit is related to reactivation of the shear zone during the main deformation of the Itajaí basin (530 Ma). The IPSZ evolved from thrust to right lateral fault (Rostirolla et al., 1999) and built up a well marked structural control in the deposit, that is associated to fractured gneiss and granitic rocks with remarkable silicification. We have examined fluid inclusions within quartz from pre-, syn- and post-mineralization veins to provide constraints on the role of fluid activity and genesis of the deposit. Thirteen fluid inclusions associations from 5 veins, encompassing 630 fluid inclusions were analyzed by Raman spectroscopy and microthermometry. Fluid inclusions have trapped a saline aqueous fluid with salinity ranging from 1 to 10 wt.% eq. NaCl. No gas has been detected in inclusions. Large variations of salinity are observed inside fluid inclusion assemblages (FIA) probably indicating a mixing process between deep and surface waters. Homogenization temperatures are well distributed in the range 100- 180 °C.},
note = {ACTI},
keywords = {ER4},
pubstate = {published},
tppubtype = {conference}
}
The Itajaí-Perimbó shear zone (IPSZ), in southern Brazil, is the northern boundary of the Brasiliano/ Pan-African Dom Feliciano Belt, whose evolution is related to the West Gondwana collage. This NE-SW shear zone is the limit between the Itajaí basin, at NW, and the Brusque group (part of Dom Feliciano Belt), at SE. The Itajaí basin is a Neoproterozoic foreland basin, with sedimentation occurring between 600 to 560 Ma. Brusque group is composed of schists and marbles with granitoids, that evolved from 900 to 540 Ma (Basei et al., 2011ab). The IPSZ hosts a lead and zinc (copper and silver) ore deposit at the Ribeirão da Prata mine. Galena, sphalerite, chalcopyrite and pyrite are the primary ore minerals. Covellite, goethite, malachite azurite (cerussite and pyromorphite) represent the secondary ore paragenesis (Biondi et al., 1992). The formation of this deposit is related to reactivation of the shear zone during the main deformation of the Itajaí basin (530 Ma). The IPSZ evolved from thrust to right lateral fault (Rostirolla et al., 1999) and built up a well marked structural control in the deposit, that is associated to fractured gneiss and granitic rocks with remarkable silicification. We have examined fluid inclusions within quartz from pre-, syn- and post-mineralization veins to provide constraints on the role of fluid activity and genesis of the deposit. Thirteen fluid inclusions associations from 5 veins, encompassing 630 fluid inclusions were analyzed by Raman spectroscopy and microthermometry. Fluid inclusions have trapped a saline aqueous fluid with salinity ranging from 1 to 10 wt.% eq. NaCl. No gas has been detected in inclusions. Large variations of salinity are observed inside fluid inclusion assemblages (FIA) probably indicating a mixing process between deep and surface waters. Homogenization temperatures are well distributed in the range 100- 180 °C. |
2017Conférence ER4 Auteurs : Althoff, F; Dubois, Michel; Haldich, I W; Ronchi, L H; Ronchi, F C Constraints on the evolution of the Itajaí-Perimbó shear zone, southern Brazil, provided by fluid inclusions XXIVth European Current Research On Fluid Inclusions (ECROFI), 25-29 juin, Nancy, 2017, (ACTI). Résumé @conference{Althoff2017a,
title = {Constraints on the evolution of the Itajaí-Perimbó shear zone, southern Brazil, provided by fluid inclusions},
author = {F Althoff and Michel Dubois and I W Haldich and L H Ronchi and F C Ronchi},
year = {2017},
date = {2017-01-01},
booktitle = {XXIVth European Current Research On Fluid Inclusions (ECROFI), 25-29 juin, Nancy},
abstract = {The Itajaí-Perimbó shear zone (IPSZ) is exposed in the Catarinense Shield, southern Brazil. It defines the contact between the Dom Feliciano Belt (Cryogenian) and the Itajaí Foreland Basin (Ediacaran). The IPSZ evolved from oblique-thrust to strike-slip fault during the Brasiliano / Pan-African orogenic cycle, and was reactivated affecting Late Permian rocks in the Paraná basin (Rostirolla et al., 2003). The oldest rock known in the Dom Feliciano belt is the A-type Parapente granite (843 +/- 12 Ma; Basei et al., 2008), that outcrops inside the IPSZ. The Parapente granite is older than the IPSZ and suffered only brittle- (feldspars) plastic (quartz) deformation, with development of low grade mylonites and phyllonites. The pressure-temperature (P-T) conditions throughout the evolution of the IPSZ were evaluated using fluid inclusions from the Parapente granite. Different quartz generations were identified according to their microstructural features. Homogenization temperatures range from 193 °C in quartz from the less deformed granite (FIP 25), 224 to 180 ºC in quartz from a deformed vein in accordance with the granite foliation (FN6), 180 to 169 ºC in quartz from a deformed vein that cuts the granite foliation (FIP 29), and 165 to 138°C in quartz porphyroblasts from the phyllonite (FIP 6 and FIP 22). All fluid populations are mainly saline waters of low to medium salinity (1-10 wt% eq. NaCl), with exceptionally a low gas content (CO2 and N2) in one sample (FN6). Depths estimated from fluid inclusion isochores indicate at least three crustal levels where the shear zone may have been active (from ~20 km to ~10 km). P-T conditions of formation of phyllonites are estimated at 350 °C and 4 kbar and probably determine the end of the evolution of the IPSZ. The variation in depth of almost 10 km implies that the shear zone operated as a thrust fault},
note = {ACTI},
keywords = {ER4},
pubstate = {published},
tppubtype = {conference}
}
The Itajaí-Perimbó shear zone (IPSZ) is exposed in the Catarinense Shield, southern Brazil. It defines the contact between the Dom Feliciano Belt (Cryogenian) and the Itajaí Foreland Basin (Ediacaran). The IPSZ evolved from oblique-thrust to strike-slip fault during the Brasiliano / Pan-African orogenic cycle, and was reactivated affecting Late Permian rocks in the Paraná basin (Rostirolla et al., 2003). The oldest rock known in the Dom Feliciano belt is the A-type Parapente granite (843 +/- 12 Ma; Basei et al., 2008), that outcrops inside the IPSZ. The Parapente granite is older than the IPSZ and suffered only brittle- (feldspars) plastic (quartz) deformation, with development of low grade mylonites and phyllonites. The pressure-temperature (P-T) conditions throughout the evolution of the IPSZ were evaluated using fluid inclusions from the Parapente granite. Different quartz generations were identified according to their microstructural features. Homogenization temperatures range from 193 °C in quartz from the less deformed granite (FIP 25), 224 to 180 ºC in quartz from a deformed vein in accordance with the granite foliation (FN6), 180 to 169 ºC in quartz from a deformed vein that cuts the granite foliation (FIP 29), and 165 to 138°C in quartz porphyroblasts from the phyllonite (FIP 6 and FIP 22). All fluid populations are mainly saline waters of low to medium salinity (1-10 wt% eq. NaCl), with exceptionally a low gas content (CO2 and N2) in one sample (FN6). Depths estimated from fluid inclusion isochores indicate at least three crustal levels where the shear zone may have been active (from ~20 km to ~10 km). P-T conditions of formation of phyllonites are estimated at 350 °C and 4 kbar and probably determine the end of the evolution of the IPSZ. The variation in depth of almost 10 km implies that the shear zone operated as a thrust fault |
2017Conférence ER4 Auteurs : Crognier, Nemo; Hoareau, Guilhem; Aubourg, Charles; Dubois, Michel; Lacroix, Brice; Branellec, Mathieu; Callot, Jean-Paul; Vennemann, Torsten Syn-orogenic fluid flow in the Jaca basin (South Pyrenean Fold and Thrust Belt) from fracture and vein analyses European Geosciences Union, General Assembly 2017, 23-28 April 2017, Vienna (Australie), 2017, (ACTI). Résumé @conference{Crognier2017,
title = {Syn-orogenic fluid flow in the Jaca basin (South Pyrenean Fold and Thrust Belt) from fracture and vein analyses},
author = {Nemo Crognier and Guilhem Hoareau and Charles Aubourg and Michel Dubois and Brice Lacroix and Mathieu Branellec and Jean-Paul Callot and Torsten Vennemann},
year = {2017},
date = {2017-01-01},
booktitle = {European Geosciences Union, General Assembly 2017, 23-28 April 2017, Vienna (Australie)},
abstract = {This study aims at understanding the origin and nature of syn-orogenic fluid flow in the jaca basin from the south pyrenean fold and thrust-belt, recorded in calcite and quartz veins of the sierras interiores (spain) and the turbiditic basin, which cover upper cretaceous to late eocene syntectonic deposits. the fracture network consists of a classical pattern of transverse and longitudinal fractures with respect to folds, that we propose to be related to layer parallel shortening (lps) and folding respectively. veins filled equally about the third of fractures in the carbonate shelf and turbidites. carbon and oxygen isotopes of calcite veins mostly indicate precipitation from isotopically buffered water, consistent with high water-rock interaction. in the sierras interiores, petrographical observations and fluid inclusion microthermometry are consistent with two distinct stages of precipitation. the first stage is characterized by relatively low th and low salinities (155-205◦ c and 0.5-3.2 wt% eq. nacl respectively). the second stage, characterized both by the formation of mode-i joints and by mode-i reactivation of preexisting veins, shows higher th and salinities (215-270◦c and 2.2-5.7 wt% eq. nacl respectively). low salinities recorded during the first stage suggest dilution of marine water by fresh water expelled by the smectite to illite transformation at t < 200◦c. waters recorded in the second stage are interpreted to have interacted with underlying triassic evaporites and flowed along major thrusts before vein precipitation, which are locally in thermal disequilibrium with hostrocks. we suggest the transition from a rather closed hydrological system during the first stage of vein formation, interpreted to have occurred during eaux-chaudes thrusting (upper lutetian-bartonian), to a more open hydrological system during the second stage, which likely occurred during gavarnie thrusting (priabonian-early rupelian). this evolution exhibits many similarities with other fold-and-thrust belts, except in the limited involvement of meteoric water. finally, we also document the migration in space and time of hydrothermal pulses along the south pyrenean foreland basin, related to the westward propagation of major thrusts during the pyrenean orogeny},
note = {ACTI},
keywords = {ER4},
pubstate = {published},
tppubtype = {conference}
}
This study aims at understanding the origin and nature of syn-orogenic fluid flow in the jaca basin from the south pyrenean fold and thrust-belt, recorded in calcite and quartz veins of the sierras interiores (spain) and the turbiditic basin, which cover upper cretaceous to late eocene syntectonic deposits. the fracture network consists of a classical pattern of transverse and longitudinal fractures with respect to folds, that we propose to be related to layer parallel shortening (lps) and folding respectively. veins filled equally about the third of fractures in the carbonate shelf and turbidites. carbon and oxygen isotopes of calcite veins mostly indicate precipitation from isotopically buffered water, consistent with high water-rock interaction. in the sierras interiores, petrographical observations and fluid inclusion microthermometry are consistent with two distinct stages of precipitation. the first stage is characterized by relatively low th and low salinities (155-205◦ c and 0.5-3.2 wt% eq. nacl respectively). the second stage, characterized both by the formation of mode-i joints and by mode-i reactivation of preexisting veins, shows higher th and salinities (215-270◦c and 2.2-5.7 wt% eq. nacl respectively). low salinities recorded during the first stage suggest dilution of marine water by fresh water expelled by the smectite to illite transformation at t < 200◦c. waters recorded in the second stage are interpreted to have interacted with underlying triassic evaporites and flowed along major thrusts before vein precipitation, which are locally in thermal disequilibrium with hostrocks. we suggest the transition from a rather closed hydrological system during the first stage of vein formation, interpreted to have occurred during eaux-chaudes thrusting (upper lutetian-bartonian), to a more open hydrological system during the second stage, which likely occurred during gavarnie thrusting (priabonian-early rupelian). this evolution exhibits many similarities with other fold-and-thrust belts, except in the limited involvement of meteoric water. finally, we also document the migration in space and time of hydrothermal pulses along the south pyrenean foreland basin, related to the westward propagation of major thrusts during the pyrenean orogeny |
2017Conférence ER4 Auteurs : Dusséaux, Camille; Gebelin, Aude; Boulvais, Philippe; Dubois, Michel; Gardien, Véronique; Mulch, Andreas Deep penetration of meteoric water in Variscan ductile shear zones (Western Europe) Goldschmidt Conference, 14-18 août 2017, Paris, 2017, (ACTI). Résumé @conference{Dusseaux2017,
title = {Deep penetration of meteoric water in Variscan ductile shear zones (Western Europe)},
author = {Camille Dusséaux and Aude Gebelin and Philippe Boulvais and Michel Dubois and Véronique Gardien and Andreas Mulch},
year = {2017},
date = {2017-01-01},
booktitle = {Goldschmidt Conference, 14-18 août 2017, Paris},
abstract = {The variscan belt of western europe is well exposed in the armorican massif (am) and the french massif central (fmc). they are both characterized by strike-slip shear zones and detachment zones that developed as a consequence of late carboniferous post-orogenic extension. syntectonic peraluminous granites are spatially associated with strike-slip shear zones and form the footwall of the detachment zones. therefore, the structural, geochemical and geochronological study of synextensional granitic plutons greatly helps in understanding extension phenomena. combining microstructural, hydrogen isotope (gd) and fluid inclusion analysis of granitic mylonite samples, we aim at understanding the spatial and temporal relationships among microstructure development, localization of strain and fluidrock interaction},
note = {ACTI},
keywords = {ER4},
pubstate = {published},
tppubtype = {conference}
}
The variscan belt of western europe is well exposed in the armorican massif (am) and the french massif central (fmc). they are both characterized by strike-slip shear zones and detachment zones that developed as a consequence of late carboniferous post-orogenic extension. syntectonic peraluminous granites are spatially associated with strike-slip shear zones and form the footwall of the detachment zones. therefore, the structural, geochemical and geochronological study of synextensional granitic plutons greatly helps in understanding extension phenomena. combining microstructural, hydrogen isotope (gd) and fluid inclusion analysis of granitic mylonite samples, we aim at understanding the spatial and temporal relationships among microstructure development, localization of strain and fluidrock interaction |
2017Conférence ER4 Auteurs : Kieffer, M; Nasraoui, M; Dubois, Michel; Lavina, P Mineralogy and fluid inclusions of amethyst veins, Auvergne, Central Massif France: Implication for hydrothermal évolution and genesis XXIVth European Current Research On Fluid Inclusions (ECROFI), 25-29 juin, Nancy, 2017, (ACTI). Résumé @conference{Kieffer2017,
title = {Mineralogy and fluid inclusions of amethyst veins, Auvergne, Central Massif France: Implication for hydrothermal évolution and genesis},
author = {M Kieffer and M Nasraoui and Michel Dubois and P Lavina},
year = {2017},
date = {2017-01-01},
booktitle = {XXIVth European Current Research On Fluid Inclusions (ECROFI), 25-29 juin, Nancy},
abstract = {Most amethyst deposits are closely related to granitoids. the vernet-la-varenne amethyst (auvergne district, french massif central) is hosted by several granite and grano-diorite sub-types with few aplite/pegmatite occurrences. amethyst veins have been mined between the 17th and the 20th centuries, but the ore genesis and the hydrothermal evolution remain poorly understood because of the lack of systematic studies of field geology, mineralogy and geochemistry. in the studied area, amethyst veins are mainly oriented n110-n130 and are intimately related to silicified zones with progressive change of quartz colour ranging from milk to purple. two main paragenetic stages of amethyst formation have been recognized based on petrographic observations. the first paragenesis si-s-cu-as-sb-rich is composed of milky-quartz, pyrite and cu-fe sulphides solid solutions with an as end-member (tennantite) and a sb end-member (tetrahedrite), whereas the second paragenesis is as-sb-free and mainly composed of milky-quartz and chalcopyrite. the fluid inclusion study reveals that the amethyst veins were formed from low temperature (100 to 300 °c) and low (<3.5 % equiv. wt.% nacl), to high-salinity fluids (18 to 22 eq wt.% nacl). a subordinate aqueous fluid of moderate salinity has been also recorded (14 eq wt.% nacl). temperature and salinity variations suggest the occurrence of mixing and dilution of early magmatic fluids with external fluids (meteoric and/or evaporate leaching). further oxygen and hydrogen isotopic data are needed to precise the proposed hypothesis.},
note = {ACTI},
keywords = {ER4},
pubstate = {published},
tppubtype = {conference}
}
Most amethyst deposits are closely related to granitoids. the vernet-la-varenne amethyst (auvergne district, french massif central) is hosted by several granite and grano-diorite sub-types with few aplite/pegmatite occurrences. amethyst veins have been mined between the 17th and the 20th centuries, but the ore genesis and the hydrothermal evolution remain poorly understood because of the lack of systematic studies of field geology, mineralogy and geochemistry. in the studied area, amethyst veins are mainly oriented n110-n130 and are intimately related to silicified zones with progressive change of quartz colour ranging from milk to purple. two main paragenetic stages of amethyst formation have been recognized based on petrographic observations. the first paragenesis si-s-cu-as-sb-rich is composed of milky-quartz, pyrite and cu-fe sulphides solid solutions with an as end-member (tennantite) and a sb end-member (tetrahedrite), whereas the second paragenesis is as-sb-free and mainly composed of milky-quartz and chalcopyrite. the fluid inclusion study reveals that the amethyst veins were formed from low temperature (100 to 300 °c) and low (<3.5 % equiv. wt.% nacl), to high-salinity fluids (18 to 22 eq wt.% nacl). a subordinate aqueous fluid of moderate salinity has been also recorded (14 eq wt.% nacl). temperature and salinity variations suggest the occurrence of mixing and dilution of early magmatic fluids with external fluids (meteoric and/or evaporate leaching). further oxygen and hydrogen isotopic data are needed to precise the proposed hypothesis. |
2017Conférence ER4 Auteurs : Nasraoui, Mohamed; Dubois, Michel; Zinbi, Y; Rottier, B; Misdariis, N Relationship between magma and Cu-mineralization in Eastern Jbilet (Morocco) XXIVth European Current Research On Fluid Inclusions (ECROFI), 25-29 juin, Nancy, 2017, (ACTI). Résumé @conference{Nasraoui2017,
title = {Relationship between magma and Cu-mineralization in Eastern Jbilet (Morocco)},
author = {Mohamed Nasraoui and Michel Dubois and Y Zinbi and B Rottier and N Misdariis},
year = {2017},
date = {2017-01-01},
booktitle = {XXIVth European Current Research On Fluid Inclusions (ECROFI), 25-29 juin, Nancy},
abstract = {Copper hydrothermal vein deposits are orebodies formed by precipitation of metal sulphides from hydrothermal fluids released from cooling magmatic sources, eventually mixed with fluids of other sources. several processes are controlling the precipitation of cu-hosting minerals including fluid mixing, temperature, eh and ph changes. identifying new cu deposits in morocco is extremely essential for the country economy. however, the discovery of new deposits is limited by the lack of understanding of metallogenic processes involved in some districts like the one of eastern jbilet, the target of the present work. the eastern jbilet area, belonging to the moroccan hercynian belt, hosts numerous cu-mineralized veins. these veins are distributed over more than 20 km around the city of kelaa sraghna. up to now no genetic model of these cu-veins has been proposed for such deposits. veins hosting sulfide mineralization show multiphase precipitation process mainly of pyrite, chalcopyrite, with minor bornite, covellite, and chalcocite. gangue minerals are represented by quartz and carbonates including calcite, dolomite, ankerite and siderite. our recent field investigations show discreet occurrence of both volcanic and plutonic rocks. the present work focusses on the genetic relationship between cu-veins versus the local magmatism occurrences, and will discuss implications for spatial distribution of the mineralization. field work combining mapping/geophysical exploration and drilling campaign shows that the mineralization process could be linked to small appendices of plutonic rocks probably belonging to a large volcanic system (pillow-lava and basic dykes). a comparison of fluid inclusion results, performed on hydrothermal quartz coming from outcrops and shallow galleries (down to –77 m), provides evidence of ptx fluid signatures with temperature less than 200 °c, depth less than 4 km and high nacl (>20 %) content. no boiling process have been detected. from a genetic point of view copper could be transported as cl-complexes and the precipitation of sulfide-bearing minerals seems to be temperature and ph-dependent. these data suggest that the lateral and in-depth distribution of the mineralization could be linked to a large magmatic system and give key perspective for further exploration work in eastern jbilet.},
note = {ACTI},
keywords = {ER4},
pubstate = {published},
tppubtype = {conference}
}
Copper hydrothermal vein deposits are orebodies formed by precipitation of metal sulphides from hydrothermal fluids released from cooling magmatic sources, eventually mixed with fluids of other sources. several processes are controlling the precipitation of cu-hosting minerals including fluid mixing, temperature, eh and ph changes. identifying new cu deposits in morocco is extremely essential for the country economy. however, the discovery of new deposits is limited by the lack of understanding of metallogenic processes involved in some districts like the one of eastern jbilet, the target of the present work. the eastern jbilet area, belonging to the moroccan hercynian belt, hosts numerous cu-mineralized veins. these veins are distributed over more than 20 km around the city of kelaa sraghna. up to now no genetic model of these cu-veins has been proposed for such deposits. veins hosting sulfide mineralization show multiphase precipitation process mainly of pyrite, chalcopyrite, with minor bornite, covellite, and chalcocite. gangue minerals are represented by quartz and carbonates including calcite, dolomite, ankerite and siderite. our recent field investigations show discreet occurrence of both volcanic and plutonic rocks. the present work focusses on the genetic relationship between cu-veins versus the local magmatism occurrences, and will discuss implications for spatial distribution of the mineralization. field work combining mapping/geophysical exploration and drilling campaign shows that the mineralization process could be linked to small appendices of plutonic rocks probably belonging to a large volcanic system (pillow-lava and basic dykes). a comparison of fluid inclusion results, performed on hydrothermal quartz coming from outcrops and shallow galleries (down to –77 m), provides evidence of ptx fluid signatures with temperature less than 200 °c, depth less than 4 km and high nacl (>20 %) content. no boiling process have been detected. from a genetic point of view copper could be transported as cl-complexes and the precipitation of sulfide-bearing minerals seems to be temperature and ph-dependent. these data suggest that the lateral and in-depth distribution of the mineralization could be linked to a large magmatic system and give key perspective for further exploration work in eastern jbilet. |
2016Article de journal ER4 Auteurs : Gardien, Véronique; Rabinowicz, Michel; Vigneresse, Jean-Louis; Dubois, Michel; Boulvais, Philippe; Martini, Rossana Long-lived interaction between hydrothermal and magmatic fluids in the Soultz-Sous-Forêts granitic system (Rhine Graben, France) Dans: Lithos, vol. 246-247, p. 110-127, 2016, (ACL). Résumé @article{Gardien2016,
title = {Long-lived interaction between hydrothermal and magmatic fluids in the Soultz-Sous-Forêts granitic system (Rhine Graben, France)},
author = {Véronique Gardien and Michel Rabinowicz and Jean-Louis Vigneresse and Michel Dubois and Philippe Boulvais and Rossana Martini},
year = {2016},
date = {2016-01-01},
journal = {Lithos},
volume = {246-247},
pages = {110-127},
abstract = {The 5 km deep drilling at soultz-sous-forêts samples a granitic intrusion under its sedimentary cover. core samples at different depths allow study of the evolving conditions of fluid-rock interaction, from the syn-tectonic emplacement of hercynian granites at depth until post-cooling history and alteration close to the surface. hydrogen, carbon and oxygen isotope compositions of co2 and h2o have been measured in fluid inclusions trapped in magmatic quartz within samples collected along the drill core. early fluid inclusions assemblage (fia) contains aqueous carbonic fluids whereas the latest fia are h2o-rich. in the early fia, the amount of co2 and the δ13c value both decrease with depth, revealing two distinct sources of carbon, one likely derived from sedimentary carbonates (δ13c = − 2‰ v-pdb) and another from the continental crust (δ13c = − 9‰ v-pdb). the carbon isotope composition of bulk granites indicates a third carbon source of organic derivation (δ13c = − 20‰ v-pdb). using a δd - δ18o plot, we argue that the water trapped in quartz grains is mainly of meteoric origin somewhat mixed with magmatic water. the emplacement of the soultz-sous-forêts granite pluton occurred in a north 030–040° wrench zone. after consolidation of the granite mush at ~ 600 °c, sinistral shear (γ ~ 1) concentrated the final leucocratic melt in vertical planes oriented along (σ1, σ2). crystallization of this residual leucocratic melt occurred while shearing was still active. at a temperature of ~ 550 °c, crystallization ended with the formation of vertical quartz veins spaced about 5 mm, and exhibiting a width of several cm. the quartz veins form a connected network of a few kilometers in height, generated during hydrothermal contraction of the intrusion. quartz crystallization led to the exsolution of 30% by volume of the aqueous fluid. as quartz grains were the latest solid phase still plastic, shearing localized inside the connected quartz network. aqueous fluid was thus concentrated in these vertical channels. eventually, when the channels intersected the top of the crack network, water boiling caused the formation of primary inclusions. at the same temperature, the saline magmatic waters, which were denser than the meteoric waters, initiated thermohaline convection with the buoyant “cold” hydrothermal water layer. this mechanism can explain the mixing of surface and deep-seated fluids in the same primary inclusions trapped during the crystallization of magmatic minerals. this study, which separately considers fluid-rock interactions at the level of successive mineral facies, brings new insights into how fluids may be different, their origin and composition, and depending on tectono-thermal conditions, bears implications for eventual ore forming processes.},
note = {ACL},
keywords = {ER4},
pubstate = {published},
tppubtype = {article}
}
The 5 km deep drilling at soultz-sous-forêts samples a granitic intrusion under its sedimentary cover. core samples at different depths allow study of the evolving conditions of fluid-rock interaction, from the syn-tectonic emplacement of hercynian granites at depth until post-cooling history and alteration close to the surface. hydrogen, carbon and oxygen isotope compositions of co2 and h2o have been measured in fluid inclusions trapped in magmatic quartz within samples collected along the drill core. early fluid inclusions assemblage (fia) contains aqueous carbonic fluids whereas the latest fia are h2o-rich. in the early fia, the amount of co2 and the δ13c value both decrease with depth, revealing two distinct sources of carbon, one likely derived from sedimentary carbonates (δ13c = − 2‰ v-pdb) and another from the continental crust (δ13c = − 9‰ v-pdb). the carbon isotope composition of bulk granites indicates a third carbon source of organic derivation (δ13c = − 20‰ v-pdb). using a δd - δ18o plot, we argue that the water trapped in quartz grains is mainly of meteoric origin somewhat mixed with magmatic water. the emplacement of the soultz-sous-forêts granite pluton occurred in a north 030–040° wrench zone. after consolidation of the granite mush at ~ 600 °c, sinistral shear (γ ~ 1) concentrated the final leucocratic melt in vertical planes oriented along (σ1, σ2). crystallization of this residual leucocratic melt occurred while shearing was still active. at a temperature of ~ 550 °c, crystallization ended with the formation of vertical quartz veins spaced about 5 mm, and exhibiting a width of several cm. the quartz veins form a connected network of a few kilometers in height, generated during hydrothermal contraction of the intrusion. quartz crystallization led to the exsolution of 30% by volume of the aqueous fluid. as quartz grains were the latest solid phase still plastic, shearing localized inside the connected quartz network. aqueous fluid was thus concentrated in these vertical channels. eventually, when the channels intersected the top of the crack network, water boiling caused the formation of primary inclusions. at the same temperature, the saline magmatic waters, which were denser than the meteoric waters, initiated thermohaline convection with the buoyant “cold” hydrothermal water layer. this mechanism can explain the mixing of surface and deep-seated fluids in the same primary inclusions trapped during the crystallization of magmatic minerals. this study, which separately considers fluid-rock interactions at the level of successive mineral facies, brings new insights into how fluids may be different, their origin and composition, and depending on tectono-thermal conditions, bears implications for eventual ore forming processes. |
2016Article de journal ER4 Auteurs : Grosjean, Anne-Sabine; Gardien, Véronique; Dubois, Michel; Boulvais, Philippe; Martini, Rossana; Vennemann, Torsten; Pittet, Bernard Sediment provenance during Alpine orogeny: fluid inclusions and stable isotopes on quartz–calcite veins from detritic pebbles Dans: Swiss Journal of Geosciences, vol. 109, no. 3, p. 329-344, 2016, (ACL). Résumé @article{Grosjean2016,
title = {Sediment provenance during Alpine orogeny: fluid inclusions and stable isotopes on quartz–calcite veins from detritic pebbles},
author = {Anne-Sabine Grosjean and Véronique Gardien and Michel Dubois and Philippe Boulvais and Rossana Martini and Torsten Vennemann and Bernard Pittet},
year = {2016},
date = {2016-01-01},
journal = {Swiss Journal of Geosciences},
volume = {109},
number = {3},
pages = {329-344},
abstract = {An innovative multidisciplinary approach was used on quartz–calcite veins that crosscut pebbles of several lithologies from the french south alpine foreland basin to discern the source of detrital sediments. microthermometric results indicate that inclusions contain low to moderate salinity (0.9–9.8 wt% eq. nacl) fluids. oxygen and carbon isotope compositions of quartz and calcite (δ18o mean at +24.1 and +24.7 ‰ respectively (v-smow) and δ13c from −1.1 to +2.0 ‰ (v-pdb)) are comparable with the composition of their host rocks (δ18o from +17 to +24.3 ‰ and δ13c from −4 to +1.4 ‰). the calculated δ18o and δ13c values of the fluid trapped in quartz and calcite range from +9.3 to +21.9 ‰, and from −2.6 to +4.1 ‰ respectively. these data suggest isotopic buffering of the fluid by the host rocks. fluid trapping conditions were 105–185 mpa and 175–310 °c. using a lithostatic gradient, the conditions of fluid entrapment correspond to a depth of vein formation from 4 to 7 km. petrographic and geochemical data obtained on the host rocks, their veins and fluid inclusions suggest that the source of the conglomerates is the inner part of the alps rather than reliefs surrounding the foreland basin. the study of fluid inclusions in veins provides a powerful and innovative approach to link the production of detrital sediments with tectonic events, to trace the provenance of conglomerates and to reconstruct the regional geometry of the drainage system.},
note = {ACL},
keywords = {ER4},
pubstate = {published},
tppubtype = {article}
}
An innovative multidisciplinary approach was used on quartz–calcite veins that crosscut pebbles of several lithologies from the french south alpine foreland basin to discern the source of detrital sediments. microthermometric results indicate that inclusions contain low to moderate salinity (0.9–9.8 wt% eq. nacl) fluids. oxygen and carbon isotope compositions of quartz and calcite (δ18o mean at +24.1 and +24.7 ‰ respectively (v-smow) and δ13c from −1.1 to +2.0 ‰ (v-pdb)) are comparable with the composition of their host rocks (δ18o from +17 to +24.3 ‰ and δ13c from −4 to +1.4 ‰). the calculated δ18o and δ13c values of the fluid trapped in quartz and calcite range from +9.3 to +21.9 ‰, and from −2.6 to +4.1 ‰ respectively. these data suggest isotopic buffering of the fluid by the host rocks. fluid trapping conditions were 105–185 mpa and 175–310 °c. using a lithostatic gradient, the conditions of fluid entrapment correspond to a depth of vein formation from 4 to 7 km. petrographic and geochemical data obtained on the host rocks, their veins and fluid inclusions suggest that the source of the conglomerates is the inner part of the alps rather than reliefs surrounding the foreland basin. the study of fluid inclusions in veins provides a powerful and innovative approach to link the production of detrital sediments with tectonic events, to trace the provenance of conglomerates and to reconstruct the regional geometry of the drainage system. |
2016Conférence ER4 Auteurs : Kieffer, M; Nasraoui, M; Dubois, Michel; Lavina, P Towards a metallogenic model of amethyst mineralisation, a fluid inclusions study (Vernet-la-Varenne, Auvergne, France) Resources & Innovative Geology RIG-2016, 4-7 avril 2016, Montpellier, 2016, (ACTI). @conference{Kieffer2016,
title = {Towards a metallogenic model of amethyst mineralisation, a fluid inclusions study (Vernet-la-Varenne, Auvergne, France)},
author = {M Kieffer and M Nasraoui and Michel Dubois and P Lavina},
year = {2016},
date = {2016-01-01},
booktitle = {Resources & Innovative Geology RIG-2016, 4-7 avril 2016, Montpellier},
note = {ACTI},
keywords = {ER4},
pubstate = {published},
tppubtype = {conference}
}
|
2016Article de journal ER4 Auteurs : N'diaye, Ismaïla; Essaifi, Abderrahim; Dubois, Michel; Lacroix, Brice; Goodenough, Kathryn-M.; Maacha, Lhou Fluid flow and polymetallic sulfide mineralization in the Kettara shear zone (Jebilet Massif, Variscan Belt, Morocco) Dans: Journal of African Earth Sciences, vol. 119, p. 17-37, 2016, (ACL). Résumé @article{Ndiaye2016,
title = {Fluid flow and polymetallic sulfide mineralization in the Kettara shear zone (Jebilet Massif, Variscan Belt, Morocco)},
author = {Ismaïla N'diaye and Abderrahim Essaifi and Michel Dubois and Brice Lacroix and Kathryn-M. Goodenough and Lhou Maacha},
year = {2016},
date = {2016-01-01},
journal = {Journal of African Earth Sciences},
volume = {119},
pages = {17-37},
abstract = {The kettara shear zone is a regional wrench shear zone within the jebilet massif of western morocco, part of the variscan orogenic belt. this massif is characterized by bimodal magmatism, largely intrusive, and by a number of polymetallic massive sulfide deposits. a syntectonic mafic-ultramafic intrusion and an adjacent, deformed pyrrhotite-rich massive sulfide deposit are located within a ‘compressional jog’ of the shear zone. hydrothermal alteration in both the intrusion and the wall rocks adjacent to the deposit is characterized by syntectonic replacement processes leading to formation of chlorite-schists and quartz ± calcite veins. fluid inclusions in mineralized (pyrrhotite-bearing) quartz veins from the wall rocks adjacent to the deposit and in veins associated with chlorite-schists within the intrusion indicate a prevalence of h2o-co2-ch4-n2 and h2o-salt fluid systems. in the mineralized veins the fluid shows reducing conditions, with gas dominated by ch4 and n2 and salinities around 7.5 wt% nacl, whereas in the chlorite shear zones fluid is co2 dominated and salinities are higher than 23 wt% nacl. hydrogen and oxygen isotopic compositions of chlorite and quartz are similar and demonstrate involvement of metamorphic water in both the deposit and the intrusion. the data are consistent with a regional metamorphic fluid flow through the kettara shear zone. the migrating metamorphic fluids were reduced in the organic matter-rich host rocks leading to deposition of sulfides in the mineralized veins. there are two possible hypotheses for the origin of these mineralized veins: either they were formed during deformation and remobilization of a syn-sedimentary massive sulfide deposit, or they were formed synchronously with the sulfide deposit during development of the kettara shear zone.},
note = {ACL},
keywords = {ER4},
pubstate = {published},
tppubtype = {article}
}
The kettara shear zone is a regional wrench shear zone within the jebilet massif of western morocco, part of the variscan orogenic belt. this massif is characterized by bimodal magmatism, largely intrusive, and by a number of polymetallic massive sulfide deposits. a syntectonic mafic-ultramafic intrusion and an adjacent, deformed pyrrhotite-rich massive sulfide deposit are located within a ‘compressional jog’ of the shear zone. hydrothermal alteration in both the intrusion and the wall rocks adjacent to the deposit is characterized by syntectonic replacement processes leading to formation of chlorite-schists and quartz ± calcite veins. fluid inclusions in mineralized (pyrrhotite-bearing) quartz veins from the wall rocks adjacent to the deposit and in veins associated with chlorite-schists within the intrusion indicate a prevalence of h2o-co2-ch4-n2 and h2o-salt fluid systems. in the mineralized veins the fluid shows reducing conditions, with gas dominated by ch4 and n2 and salinities around 7.5 wt% nacl, whereas in the chlorite shear zones fluid is co2 dominated and salinities are higher than 23 wt% nacl. hydrogen and oxygen isotopic compositions of chlorite and quartz are similar and demonstrate involvement of metamorphic water in both the deposit and the intrusion. the data are consistent with a regional metamorphic fluid flow through the kettara shear zone. the migrating metamorphic fluids were reduced in the organic matter-rich host rocks leading to deposition of sulfides in the mineralized veins. there are two possible hypotheses for the origin of these mineralized veins: either they were formed during deformation and remobilization of a syn-sedimentary massive sulfide deposit, or they were formed synchronously with the sulfide deposit during development of the kettara shear zone. |
2016Article de journal ER4 Auteurs : Thiéry, Vincent; Rolin, Patrick; Dubois, Michel; Caumon, Marie-Camille; Goncalves, Philippe Reply to J. Berger's comment on the article “Discovery of metamorphic microdiamonds from the parautochthonous units of the Variscan French Massif” by Thiéry, V. et al.,. (2015), Gondwana Research 28, 954–960 Dans: Gondwana Research, vol. 38, p. 372-374, 2016, (ACL). Résumé @article{Thiery2016,
title = {Reply to J. Berger's comment on the article “Discovery of metamorphic microdiamonds from the parautochthonous units of the Variscan French Massif” by Thiéry, V. et al.,. (2015), Gondwana Research 28, 954–960},
author = {Vincent Thiéry and Patrick Rolin and Michel Dubois and Marie-Camille Caumon and Philippe Goncalves},
year = {2016},
date = {2016-01-01},
journal = {Gondwana Research},
volume = {38},
pages = {372-374},
abstract = {We are pleased to see that our recently published article (thiéry et al., 2015) is discussed (berger, 2015); in the following lines we will give some precisions and thoughts about the comment. this is not the first time that a documentation of microdiamond within metamorphic terranes is discussed (mposkos and kostopoulos, 2001; beyssac and chopin, 2003; mposkos and kostopoulos, 2003), revealing the complexity of the unraveling of uhp metamorphism. several points are to be addressed, concerning both the need for precision about the samples themselves and the need for a more thorough estimation of p–t conditions},
note = {ACL},
keywords = {ER4},
pubstate = {published},
tppubtype = {article}
}
We are pleased to see that our recently published article (thiéry et al., 2015) is discussed (berger, 2015); in the following lines we will give some precisions and thoughts about the comment. this is not the first time that a documentation of microdiamond within metamorphic terranes is discussed (mposkos and kostopoulos, 2001; beyssac and chopin, 2003; mposkos and kostopoulos, 2003), revealing the complexity of the unraveling of uhp metamorphism. several points are to be addressed, concerning both the need for precision about the samples themselves and the need for a more thorough estimation of p–t conditions |
2015Conférence ER4 Auteurs : Crognier, Nemo; Hoareau, Guilhem; Lacroix, Brice; Aubourg, Charles; Branellec, Mathieu; Dubois, Michel; Lahfid, Abdeltif; Labaume, Pierre; Suarez-Ruiz, Isabel Thermicité et circulation de fluides associés lors de la structuration du bassin d’avant-pays sud Pyrénéen (SPFB) Association des Sédimentologues Français, 13-15 octobre 2015, Chambéry, 2015, (ACTN). @conference{Crognier2015,
title = {Thermicité et circulation de fluides associés lors de la structuration du bassin d’avant-pays sud Pyrénéen (SPFB)},
author = {Nemo Crognier and Guilhem Hoareau and Brice Lacroix and Charles Aubourg and Mathieu Branellec and Michel Dubois and Abdeltif Lahfid and Pierre Labaume and Isabel Suarez-Ruiz},
year = {2015},
date = {2015-01-01},
booktitle = {Association des Sédimentologues Français, 13-15 octobre 2015, Chambéry},
note = {ACTN},
keywords = {ER4},
pubstate = {published},
tppubtype = {conference}
}
|
2015Conférence ER4 Auteurs : Crognier, Nemo; Hoareau, Guilhem; Lacroix, Brice; Aubourg, Charles; Dubois, Michel; Lahfid, Abdeltif; Labaume, Pierre; Suarez-Ruiz, Isabel Couplage des analyses isotopiques, de la microthermométrie sur inclusions fluides et du Δ47: le cas des Sierras Exteriores (Chevauchement frontal sud Pyrénéen, Espagne) Association des Sédimentologues Français, 13-15 octobre 2015, Chambéry, 2015, (ACTN). @conference{Crognier2015a,
title = {Couplage des analyses isotopiques, de la microthermométrie sur inclusions fluides et du Δ47: le cas des Sierras Exteriores (Chevauchement frontal sud Pyrénéen, Espagne)},
author = {Nemo Crognier and Guilhem Hoareau and Brice Lacroix and Charles Aubourg and Michel Dubois and Abdeltif Lahfid and Pierre Labaume and Isabel Suarez-Ruiz},
year = {2015},
date = {2015-01-01},
booktitle = {Association des Sédimentologues Français, 13-15 octobre 2015, Chambéry},
note = {ACTN},
keywords = {ER4},
pubstate = {published},
tppubtype = {conference}
}
|
2015Article de journal ER4 Auteurs : Dubois, Michel; Bourdelle, Franck Les limites du métamorphisme - La transition diagenèse-métamorphisme Dans: Géochronique, vol. 136, p. 10-14, 2015, (ACLN). @article{Dubois2015,
title = {Les limites du métamorphisme - La transition diagenèse-métamorphisme},
author = {Michel Dubois and Franck Bourdelle},
year = {2015},
date = {2015-01-01},
journal = {Géochronique},
volume = {136},
pages = {10-14},
note = {ACLN},
keywords = {ER4},
pubstate = {published},
tppubtype = {article}
}
|
2015Conférence ER4 Auteurs : Gauthier, Arnaud; Kowalski, Frederic; Lloret, Emily; Dubois, Michel Ecological and geological evolution of coal heap in urban context: what are the impact related facilities and sites overcrowding? Soils in Urban, Industrial, Traffic and Mining Areas (SUITMA 8), 20-25 September 2015, Mexico city (Mexico), 2015, (ACTI). @conference{Gauthier2015,
title = {Ecological and geological evolution of coal heap in urban context: what are the impact related facilities and sites overcrowding?},
author = {Arnaud Gauthier and Frederic Kowalski and Emily Lloret and Michel Dubois},
year = {2015},
date = {2015-01-01},
booktitle = {Soils in Urban, Industrial, Traffic and Mining Areas (SUITMA 8), 20-25 September 2015, Mexico city (Mexico)},
note = {ACTI},
keywords = {ER4},
pubstate = {published},
tppubtype = {conference}
}
|
2015Article de journal ER4 Auteurs : Hoareau, Guilhem; Odonne, Francis; Garcia, Daniel; Debroas, Elie-Jean; Monnin, Christophe; Dubois, Michel; Potdevin, Jean-Luc Burial diagenesis of the Eocene Sobrarbe delta (Ainsa Basin, Spain) inferred from dolomitic concretions Dans: Journal of Sedimentary Research, vol. 85, no. 9, p. 1037-1057, 2015, (ACL). Résumé @article{Hoareau2015,
title = {Burial diagenesis of the Eocene Sobrarbe delta (Ainsa Basin, Spain) inferred from dolomitic concretions},
author = {Guilhem Hoareau and Francis Odonne and Daniel Garcia and Elie-Jean Debroas and Christophe Monnin and Michel Dubois and Jean-Luc Potdevin},
year = {2015},
date = {2015-01-01},
journal = {Journal of Sedimentary Research},
volume = {85},
number = {9},
pages = {1037-1057},
abstract = {Little attention has been focused on the burial diagenesis of deltas deposited on active foreland-basin margins, where tectonics is likely to strongly impact fluid–rock interactions. a petrographic, geochemical, and microthermometric study of several fractured dolomite concretions and enclosing prodelta marls provides insights into the evolution of burial diagenesis in the eocene sobrarbe deltaic complex (ainsa basin, spain), and more generally, on the paleohydrology of the south pyrenean foreland basin. shallow burial diagenesis was controlled by microbial activity in marine-derived porewaters. microbial sulfate reduction was first responsible for the formation of pyrite and early calcite, followed by the growth of dolomite concretions during methanogenesis. subsequent diagenesis was limited to temperatures and depth of less than approximately 75°c and 2 km, respectively. diagenesis was recorded in porous bioturbation traces and septarian fractures found inside dolomite concretions, as well as in tectonic shear fractures. neomorphic tabular barite, found only in the bioturbation traces, is interpreted to have formed early in marine-derived porewaters. septarian fractures were then filled by fe-rich calcite and centimeter-size celestine. stable isotopes indicate that calcite probably formed in meteoric-derived waters coming from the overlying fluvial delta plain. the sulfur isotope composition of celestine is compatible with precipitation in waters of mixed parentage, but the exact origin of dissolved sulfate remains poorly constrained. in tectonic fractures, celestine precipitated coevally with calcite displaying evidence of strong fluid–rock interaction. dissolved sulfate may have migrated to the fractures during active tectonics from the late eocene to the oligocene. the paragenesis and the proposed paleohydrologic model are similar to those previously described for other deltaic systems deposited in active foreland basins, including the south pyrenean foreland basin. these features point to common diagenetic processes in syntectonic foreland-basin deltas, involving both meteoric and marine fluid sources. similar to passive margin settings, early diagenesis appears to be controlled mainly by relative variations of sea level, whereas during further burial, the development of permeable tectonic fractures is likely to facilitate the influx of basinal or continental waters into fine slope deposits, impacting the diagenetic record. these results emphasize the importance of fracture development in the fluid-flow regime of syntectonic foreland-basin deltas. they demonstrate the necessity to take this parameter into account in fluid-flow modeling of foreland-basin margins.},
note = {ACL},
keywords = {ER4},
pubstate = {published},
tppubtype = {article}
}
Little attention has been focused on the burial diagenesis of deltas deposited on active foreland-basin margins, where tectonics is likely to strongly impact fluid–rock interactions. a petrographic, geochemical, and microthermometric study of several fractured dolomite concretions and enclosing prodelta marls provides insights into the evolution of burial diagenesis in the eocene sobrarbe deltaic complex (ainsa basin, spain), and more generally, on the paleohydrology of the south pyrenean foreland basin. shallow burial diagenesis was controlled by microbial activity in marine-derived porewaters. microbial sulfate reduction was first responsible for the formation of pyrite and early calcite, followed by the growth of dolomite concretions during methanogenesis. subsequent diagenesis was limited to temperatures and depth of less than approximately 75°c and 2 km, respectively. diagenesis was recorded in porous bioturbation traces and septarian fractures found inside dolomite concretions, as well as in tectonic shear fractures. neomorphic tabular barite, found only in the bioturbation traces, is interpreted to have formed early in marine-derived porewaters. septarian fractures were then filled by fe-rich calcite and centimeter-size celestine. stable isotopes indicate that calcite probably formed in meteoric-derived waters coming from the overlying fluvial delta plain. the sulfur isotope composition of celestine is compatible with precipitation in waters of mixed parentage, but the exact origin of dissolved sulfate remains poorly constrained. in tectonic fractures, celestine precipitated coevally with calcite displaying evidence of strong fluid–rock interaction. dissolved sulfate may have migrated to the fractures during active tectonics from the late eocene to the oligocene. the paragenesis and the proposed paleohydrologic model are similar to those previously described for other deltaic systems deposited in active foreland basins, including the south pyrenean foreland basin. these features point to common diagenetic processes in syntectonic foreland-basin deltas, involving both meteoric and marine fluid sources. similar to passive margin settings, early diagenesis appears to be controlled mainly by relative variations of sea level, whereas during further burial, the development of permeable tectonic fractures is likely to facilitate the influx of basinal or continental waters into fine slope deposits, impacting the diagenetic record. these results emphasize the importance of fracture development in the fluid-flow regime of syntectonic foreland-basin deltas. they demonstrate the necessity to take this parameter into account in fluid-flow modeling of foreland-basin margins. |
2015Conférence ER4 Auteurs : N'diaye, Ismaïla; Essaifi, Abderrahim; Dubois, Michel; Lacroix, Brice; Goodenough, Kathryn-M.; Boyce, Adrian Implication of mineral geochemistry and stable isotopes in the Kettara pyrrhotite-rich Massive Sulphide deposit (Central Jebilet, Hercynian, Morocco) 13th SGA Biennal Meeting, 24-27 août 2015, Nancy, 2015, (ACTI). Résumé @conference{Ndiaye2015,
title = {Implication of mineral geochemistry and stable isotopes in the Kettara pyrrhotite-rich Massive Sulphide deposit (Central Jebilet, Hercynian, Morocco)},
author = {Ismaïla N'diaye and Abderrahim Essaifi and Michel Dubois and Brice Lacroix and Kathryn-M. Goodenough and Adrian Boyce},
year = {2015},
date = {2015-01-01},
booktitle = {13th SGA Biennal Meeting, 24-27 août 2015, Nancy},
abstract = {The kettara deposit consists of a sub-vertical pyrrhotite-rich massive sulphide hosted by sedimentary rocks, located in centre of the variscan jebilet massif, north of marrakech, morocco. the host rocks are deformed and weekly metamorphosed to greenschist facies. they are composed of pelite, sandstone, and calcareous beds and cross cut by dolerite dikes. the sulphide ore are massive to semi-massive pyrrhotite with fragments of the host schists, brecciaed pyritic ore and mineralized veins. the mineralization is composed of two main paragenetic assemblages. the first is pyrrhotite-dominant with chalcopyrite, magnetite, sphalerite, arsenopyrite, galena and native bismuth, associated with quartz, chlorite ± talc and mica gangues. a second sequence consists of pyrite-dominant with marcasite and associated with fe-rich carbonate minerals. the second sequence was formed via replacement of the pyrrhotite-rich mineralization by carbonates. chlorites associated with mineralization are fe-rich, and chlorite geothermometry indicates they were formed at c. 350 °c. oxygen and hydrogen isotope indicate that these chlorites were formed from metamorphic fluid.},
note = {ACTI},
keywords = {ER4},
pubstate = {published},
tppubtype = {conference}
}
The kettara deposit consists of a sub-vertical pyrrhotite-rich massive sulphide hosted by sedimentary rocks, located in centre of the variscan jebilet massif, north of marrakech, morocco. the host rocks are deformed and weekly metamorphosed to greenschist facies. they are composed of pelite, sandstone, and calcareous beds and cross cut by dolerite dikes. the sulphide ore are massive to semi-massive pyrrhotite with fragments of the host schists, brecciaed pyritic ore and mineralized veins. the mineralization is composed of two main paragenetic assemblages. the first is pyrrhotite-dominant with chalcopyrite, magnetite, sphalerite, arsenopyrite, galena and native bismuth, associated with quartz, chlorite ± talc and mica gangues. a second sequence consists of pyrite-dominant with marcasite and associated with fe-rich carbonate minerals. the second sequence was formed via replacement of the pyrrhotite-rich mineralization by carbonates. chlorites associated with mineralization are fe-rich, and chlorite geothermometry indicates they were formed at c. 350 °c. oxygen and hydrogen isotope indicate that these chlorites were formed from metamorphic fluid. |
2015Article de journal ER4 Auteurs : N’Diaye, Ismaïla; Essaifi, Abderrahim; Dubois, Michel; Lacroix, Brice Mineralogy and fluid Inclusions of the Kettara massive sulphide deposit (Jebilet Massif, Variscan Belt, Morocco) Dans: Journal of Environment and Earth Science, vol. 5, no. 22, p. 98-120, 2015, (ACLN). Résumé @article{N’Diaye2015,
title = {Mineralogy and fluid Inclusions of the Kettara massive sulphide deposit (Jebilet Massif, Variscan Belt, Morocco)},
author = {Ismaïla N’Diaye and Abderrahim Essaifi and Michel Dubois and Brice Lacroix},
year = {2015},
date = {2015-01-01},
journal = {Journal of Environment and Earth Science},
volume = {5},
number = {22},
pages = {98-120},
abstract = {The kettara copper deposit is located in the centre of the jebilet massif, north of marrakech, and consists of an elongated sub-vertical pyrrhotite-rich massive sulphide lens. the host rocks consist of thin-bedded visean pelites with sandstones, calcareous beds and doleritic dykes. the host rocks have been folded, foliated, and metamorphosed to low greenschist facies conditions during the variscan orogeny. the sulphide mineralization comprises a main lens composed of massive to semi-massive pyrrhotite accompanied by chalcopyrite, magnetite, sphalerite, arsenopyrite, galena and a quartz-chlorite gangue, centimetre-scale mineralized syntectonic replacement veins in the wall rocks with the same mineralogy as the main lens, and a later pyrite-carbonate veins that cut across pyrrhotite mineralization. microthermometry and raman analysis indicate that the mineralizing fluids associated with pyrrhotite formation were h2o, n2, ch4 and co2-bearing, with low salinities (7.5 wt.%nacl), typical for low-grade metamorphism. p-t conditions from fluid inclusion studies and chlorite geothermometry indicate that pyrrhotite formation occurred at c. 200-400°c and c. 2 kbar. these characteristics indicate that the genesis of the main mineralization in the kettara massive sulphide deposit might have taken place in the transition between diagenetic and metamorphic environments or in metamorphic environment under reducing condition},
note = {ACLN},
keywords = {ER4},
pubstate = {published},
tppubtype = {article}
}
The kettara copper deposit is located in the centre of the jebilet massif, north of marrakech, and consists of an elongated sub-vertical pyrrhotite-rich massive sulphide lens. the host rocks consist of thin-bedded visean pelites with sandstones, calcareous beds and doleritic dykes. the host rocks have been folded, foliated, and metamorphosed to low greenschist facies conditions during the variscan orogeny. the sulphide mineralization comprises a main lens composed of massive to semi-massive pyrrhotite accompanied by chalcopyrite, magnetite, sphalerite, arsenopyrite, galena and a quartz-chlorite gangue, centimetre-scale mineralized syntectonic replacement veins in the wall rocks with the same mineralogy as the main lens, and a later pyrite-carbonate veins that cut across pyrrhotite mineralization. microthermometry and raman analysis indicate that the mineralizing fluids associated with pyrrhotite formation were h2o, n2, ch4 and co2-bearing, with low salinities (7.5 wt.%nacl), typical for low-grade metamorphism. p-t conditions from fluid inclusion studies and chlorite geothermometry indicate that pyrrhotite formation occurred at c. 200-400°c and c. 2 kbar. these characteristics indicate that the genesis of the main mineralization in the kettara massive sulphide deposit might have taken place in the transition between diagenetic and metamorphic environments or in metamorphic environment under reducing condition |
2015Conférence ER4 Auteurs : Ould-Moctar, Didi; Boushaba, Abdellah; Dubois, Michel Birbirites of Mauritanides belts (region of Gouérarate): petrography and geochemistry 22ème colloque International des Bassins Sédimentaires, 18-20 December 2015, Fès (Maroc), 2015, (ACTI). Résumé @conference{Ould-Moctar2015a,
title = {Birbirites of Mauritanides belts (region of Gouérarate): petrography and geochemistry},
author = {Didi Ould-Moctar and Abdellah Boushaba and Michel Dubois},
year = {2015},
date = {2015-01-01},
booktitle = {22ème colloque International des Bassins Sédimentaires, 18-20 December 2015, Fès (Maroc)},
abstract = {The terme birbirite, named after the birbir river (ethiopia), was used for the first time by duparc et al., (1927) to describe reddish and iron bearing quartzitic rocks originated from mg leaching of ultrabsic rocks of the yuddo massif. after esteban et al., (2011), the birbirite refers to cherty aspect rocks commonly associated with gold, platinum and mercury deposits, wich from the silicification of listvenites or serpentinized ultramafic rocks. petrological studies on birbirites in the world are scarce and insufficient for a complete understanding of the genesis of these rocks. this contribution is to identify the petrographical and geochemical characteristics of the birbirites from the region of gouérarate. the birbirites outcrops are commonly associated with ultramafic rocks. west africa is characterized by the mauritanides belts which stretching from morocco in the north to liberia in the south. this belt represents the western edge of the west african craton, and is commonly divided into three external, axial and internal zones. facies of axial zone are dominated by mantle formations (facies of ophiolitic suture); as result the outcrops of birbirites are spatially localized in this axial zone. in this context, region of gouérarate localized in the northern of the axial zone and represents an adequate field to: (i) study these types of rocks and (ii) provides important information on the interaction between upper mantle and water weathering. the region of gouérarate is composed by: birbirites, amphibolites, pyroxenites, eclogited pyroxenites, kyanites black rocks and laterite formations (ould moctar et al., 2014; ould moctar et al., 2015). samples of birbirite are intetensly silicified which was attested by the development of silica crust surrounding the rock. the matrix is dominantly composed of silica and small amounts of talc. silica phases are chalcedony; however many microquartz can be observed in the matrix.},
note = {ACTI},
keywords = {ER4},
pubstate = {published},
tppubtype = {conference}
}
The terme birbirite, named after the birbir river (ethiopia), was used for the first time by duparc et al., (1927) to describe reddish and iron bearing quartzitic rocks originated from mg leaching of ultrabsic rocks of the yuddo massif. after esteban et al., (2011), the birbirite refers to cherty aspect rocks commonly associated with gold, platinum and mercury deposits, wich from the silicification of listvenites or serpentinized ultramafic rocks. petrological studies on birbirites in the world are scarce and insufficient for a complete understanding of the genesis of these rocks. this contribution is to identify the petrographical and geochemical characteristics of the birbirites from the region of gouérarate. the birbirites outcrops are commonly associated with ultramafic rocks. west africa is characterized by the mauritanides belts which stretching from morocco in the north to liberia in the south. this belt represents the western edge of the west african craton, and is commonly divided into three external, axial and internal zones. facies of axial zone are dominated by mantle formations (facies of ophiolitic suture); as result the outcrops of birbirites are spatially localized in this axial zone. in this context, region of gouérarate localized in the northern of the axial zone and represents an adequate field to: (i) study these types of rocks and (ii) provides important information on the interaction between upper mantle and water weathering. the region of gouérarate is composed by: birbirites, amphibolites, pyroxenites, eclogited pyroxenites, kyanites black rocks and laterite formations (ould moctar et al., 2014; ould moctar et al., 2015). samples of birbirite are intetensly silicified which was attested by the development of silica crust surrounding the rock. the matrix is dominantly composed of silica and small amounts of talc. silica phases are chalcedony; however many microquartz can be observed in the matrix. |
2015Conférence ER4 Auteurs : Ould-Moctar, Didi; Boushaba, Abdellah; Dubois, Michel Petrographical and geochemical characteristics of ophiolite suite from Mauritanides belts: regions of Agane and Gouérarate (Mauritania) 22ème colloque International des Bassins Sédimentaires, 18-20 December 2015, Fès (Maroc), 2015, (ACTI). Résumé @conference{Ould-Moctar2015b,
title = {Petrographical and geochemical characteristics of ophiolite suite from Mauritanides belts: regions of Agane and Gouérarate (Mauritania)},
author = {Didi Ould-Moctar and Abdellah Boushaba and Michel Dubois},
year = {2015},
date = {2015-01-01},
booktitle = {22ème colloque International des Bassins Sédimentaires, 18-20 December 2015, Fès (Maroc)},
abstract = {The axial zone of mauritanides belts is characterized by the presence of a suture zone which is dominated by ophiolite suites. these ophiolitic sutures represent slices of oceanic lithosphere formed in an accretion zone and abducted within collision areas. they offer an opportunity to study the nature and the genesis of rocks forming the upper mantle. agane and gouérarate represent regions of this axial zone (ould moctar 2013; ould moctar et al., 2014). both regions portray an intense serpentinization and birbirtization affecting their mantle formations. this causes them to represent a natural laboratory for studying these two types of alteration frequently described in ophiolite suites. region of agane are composed by: serpentinites, metagranites, amphibolites, chloritoschistes, micaschiste and quartz veins. serpentinites are mainly composed of antigorite with accessory amounts of talc, hematite and quartz. later generation of serpentine is represented by micro-veins of chrysotile (fig 1.a). the matrix of metagranites consists of plagioclase, quartz and accessory minerals such as muscovite and biotite (fig 1.b). amphibolites show a matrix consisting mainly of hornblende with accessory phases of plagioclase, garnet, biotite, epidote, quartz and opaque (fig 1.c). other amphibolites show a matrix consisting mainly of epidote (fig 1.d). the matrix of micaschists is dominated by andalousite, chlorite, quartz, opaques and minor kyanite (fig 1.e). quartz veins are usually discordant and reach diameters up to 12 m. some quartz veins are rich in iron carbonate. some others are rich in tourmaline (fig 1.f) suggesting hydrothermal activity during the formation of the veins (ould moctar et al., 2015). the region of gouérarate is formed by the association of: birbirites, amphibolites, pyroxenites, eclogited pyroxenites kyanites black rocks and laterite formations. birbirites are dominantly composed of silica and small amounts of talc. silica phases are chalcedony and microquartz (fig 2.a). amphibolites consist of amphibole (actinote), plagioclase and kyanite (fig 2.b). kyanite is usually associated with actinote and exhibits small crystals intensely deformed. the presence of kyanite and actinote is confirmed by xrd. pyroxenites are dominated by of clinopyroxenes, antigorite and opaques. pyroxenites were affected by hydrothermal activity, which was indicated by the transformation of clinopyroxenes into antigorite (fig. 2.c and d). eclogitized pyroxenites consist of large clinopyroxene and garnet with interstitial phase represented by quartz and plagioclases (fig 2.e and f). many grains of rutile are also present in these eclogitized pyroxenites. kyanite black rocks are affected by intense hydrothermal evidenced by the dominance of opaques. their matrix is mainly composed of hematite, kyanite and corundum (fig 2.g and h).},
note = {ACTI},
keywords = {ER4},
pubstate = {published},
tppubtype = {conference}
}
The axial zone of mauritanides belts is characterized by the presence of a suture zone which is dominated by ophiolite suites. these ophiolitic sutures represent slices of oceanic lithosphere formed in an accretion zone and abducted within collision areas. they offer an opportunity to study the nature and the genesis of rocks forming the upper mantle. agane and gouérarate represent regions of this axial zone (ould moctar 2013; ould moctar et al., 2014). both regions portray an intense serpentinization and birbirtization affecting their mantle formations. this causes them to represent a natural laboratory for studying these two types of alteration frequently described in ophiolite suites. region of agane are composed by: serpentinites, metagranites, amphibolites, chloritoschistes, micaschiste and quartz veins. serpentinites are mainly composed of antigorite with accessory amounts of talc, hematite and quartz. later generation of serpentine is represented by micro-veins of chrysotile (fig 1.a). the matrix of metagranites consists of plagioclase, quartz and accessory minerals such as muscovite and biotite (fig 1.b). amphibolites show a matrix consisting mainly of hornblende with accessory phases of plagioclase, garnet, biotite, epidote, quartz and opaque (fig 1.c). other amphibolites show a matrix consisting mainly of epidote (fig 1.d). the matrix of micaschists is dominated by andalousite, chlorite, quartz, opaques and minor kyanite (fig 1.e). quartz veins are usually discordant and reach diameters up to 12 m. some quartz veins are rich in iron carbonate. some others are rich in tourmaline (fig 1.f) suggesting hydrothermal activity during the formation of the veins (ould moctar et al., 2015). the region of gouérarate is formed by the association of: birbirites, amphibolites, pyroxenites, eclogited pyroxenites kyanites black rocks and laterite formations. birbirites are dominantly composed of silica and small amounts of talc. silica phases are chalcedony and microquartz (fig 2.a). amphibolites consist of amphibole (actinote), plagioclase and kyanite (fig 2.b). kyanite is usually associated with actinote and exhibits small crystals intensely deformed. the presence of kyanite and actinote is confirmed by xrd. pyroxenites are dominated by of clinopyroxenes, antigorite and opaques. pyroxenites were affected by hydrothermal activity, which was indicated by the transformation of clinopyroxenes into antigorite (fig. 2.c and d). eclogitized pyroxenites consist of large clinopyroxene and garnet with interstitial phase represented by quartz and plagioclases (fig 2.e and f). many grains of rutile are also present in these eclogitized pyroxenites. kyanite black rocks are affected by intense hydrothermal evidenced by the dominance of opaques. their matrix is mainly composed of hematite, kyanite and corundum (fig 2.g and h). |
2015Article de journal ER4 Auteurs : Ould-Moctar, Didi; Boushaba, Abdellah; Dubois, Michel; Ben-Abbou, Mohamed Geochemistry and petrography of an ophiolitic suture from Mauritanides belts: regions of Agane and Gouérarate (Mauritania) Dans: Scientical, vol. 1, no. 1315, 2015, (ACLO). Résumé @article{Ould-Moctar2015c,
title = {Geochemistry and petrography of an ophiolitic suture from Mauritanides belts: regions of Agane and Gouérarate (Mauritania)},
author = {Didi Ould-Moctar and Abdellah Boushaba and Michel Dubois and Mohamed Ben-Abbou},
year = {2015},
date = {2015-01-01},
journal = {Scientical},
volume = {1},
number = {1315},
abstract = {The axial zone of mauritanides belt is characterized by the presence of numerous ophiolitic complexes. regions of agane and gouérarate represent the northern outcrops of these oceanic formations. these two regions are characterized by the abundance of completely serpentinized formations. in the region of agane, a geochemical study (major and trace elements) confirms that the protolith of serpentinite is a depleted peridotite which corresponds to former dunite-harzburgite, while other serpentinites appear to derive from ultramafic cumulates. amphibolites have an igneous protolith corresponding, to ancient basalt and gabbro formations. in contrast, birbirites from gouérarate are derived from a highly refractory protolith. these facies correspond to former dunite-harzburgite. the metamorphic conditions at gouérarate represent the highest metamorphic grade in the central mauritanides belt. this metamorphism is attested by the occurrence of kyanite black rocks and eclogited pyroxenites. in both regions, the geochemical study of ultramafic formations and associated mafic facies suggests a common origin for these rocks. these formations show a tholeiitic signature with an oceanic character.},
note = {ACLO},
keywords = {ER4},
pubstate = {published},
tppubtype = {article}
}
The axial zone of mauritanides belt is characterized by the presence of numerous ophiolitic complexes. regions of agane and gouérarate represent the northern outcrops of these oceanic formations. these two regions are characterized by the abundance of completely serpentinized formations. in the region of agane, a geochemical study (major and trace elements) confirms that the protolith of serpentinite is a depleted peridotite which corresponds to former dunite-harzburgite, while other serpentinites appear to derive from ultramafic cumulates. amphibolites have an igneous protolith corresponding, to ancient basalt and gabbro formations. in contrast, birbirites from gouérarate are derived from a highly refractory protolith. these facies correspond to former dunite-harzburgite. the metamorphic conditions at gouérarate represent the highest metamorphic grade in the central mauritanides belt. this metamorphism is attested by the occurrence of kyanite black rocks and eclogited pyroxenites. in both regions, the geochemical study of ultramafic formations and associated mafic facies suggests a common origin for these rocks. these formations show a tholeiitic signature with an oceanic character. |
2015Conférence ER4 Auteurs : Ramadan, Ghanem; Dubois, Michel; Gauthier, Arnaud; Berrehouc, G; Cheppe, Gaetan Instabilités et évolutions des cavités souterraines de la Métropole lilloise : de l’observation des phénomènes à des applications en laboratoire Journée des Doctorants IRePSE, 08 juillet 2015, CERLA - Cité Scientifique - Université Lille 1, Villeneuve d'Ascq, 2015, (ACTN). @conference{Ramadan2015,
title = {Instabilités et évolutions des cavités souterraines de la Métropole lilloise : de l’observation des phénomènes à des applications en laboratoire},
author = {Ghanem Ramadan and Michel Dubois and Arnaud Gauthier and G Berrehouc and Gaetan Cheppe},
year = {2015},
date = {2015-01-01},
booktitle = {Journée des Doctorants IRePSE, 08 juillet 2015, CERLA - Cité Scientifique - Université Lille 1, Villeneuve d'Ascq},
note = {ACTN},
keywords = {ER4},
pubstate = {published},
tppubtype = {conference}
}
|
2015Article de journal ER4 Auteurs : Thiéry, Vincent; Rolin, Patrick; Dubois, Michel; Caumon, Marie-Camille Discovery of metamorphic microdiamonds from the parautochthonous units of the Variscan French Massif Central Dans: Gondwana Research, vol. 28, no. 3, p. 954-960, 2015, (ACL). Résumé @article{Thiery2015,
title = {Discovery of metamorphic microdiamonds from the parautochthonous units of the Variscan French Massif Central},
author = {Vincent Thiéry and Patrick Rolin and Michel Dubois and Marie-Camille Caumon},
year = {2015},
date = {2015-01-01},
journal = {Gondwana Research},
volume = {28},
number = {3},
pages = {954-960},
abstract = {The variscan french massif central (fmc) is classically described as a stack of nappes with increasing metamorphism from the bottom (parautochthonous unit) to the top (lower and upper gneiss units). ultra-high pressure (uhp) metamorphism was already recognized in the uppermost units, with notably coesite-bearing rocks. we report the first finding of metamorphic microdiamonds in the parautochthonous unit, revealing that the uhp event affected the whole stack of nappes and also that the pressures reached are above what was previously expected, since the presence of diamond, according to the peak temperature estimates for this unit, indicates pressures of ca. 3 gpa (i.e. 100 km depth). at the scale of the fmc, this finding adds complexity to the established models. on a broader scale, this adds evidence of similarity between this part of the belt and other uhp variscan terranes such as the erzgebirge and the bohemian massif},
note = {ACL},
keywords = {ER4},
pubstate = {published},
tppubtype = {article}
}
The variscan french massif central (fmc) is classically described as a stack of nappes with increasing metamorphism from the bottom (parautochthonous unit) to the top (lower and upper gneiss units). ultra-high pressure (uhp) metamorphism was already recognized in the uppermost units, with notably coesite-bearing rocks. we report the first finding of metamorphic microdiamonds in the parautochthonous unit, revealing that the uhp event affected the whole stack of nappes and also that the pressures reached are above what was previously expected, since the presence of diamond, according to the peak temperature estimates for this unit, indicates pressures of ca. 3 gpa (i.e. 100 km depth). at the scale of the fmc, this finding adds complexity to the established models. on a broader scale, this adds evidence of similarity between this part of the belt and other uhp variscan terranes such as the erzgebirge and the bohemian massif |