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Philippe Rossi - One of the best experts on this subject based on the ideXlab platform.

  • middle carboniferous intracontinental subduction in the outer Zone of the variscan belt montagne noire Axial Zone french massif central multimethod geochronological approach of polyphase metamorphism
    Geological Society London Special Publications, 2014
    Co-Authors: Michel Faure, Alain Cocherie, Philippe Rossi, Julien Gache, Chloe Esnault, Catherine Guerrot, Lin Wei, Li Qiuli
    Abstract:

    In the migmatitic dome of the Montagne Noire Axial Zone (Variscan French Massif Central), mafic eclogites yield zircon and rutile U-Pb SHRIMP and SIMS ages around 315-308 Ma. These "young" dates, obtained in two different laboratories, do not comply with the geological constraints available for the study area that suggest an older age of the high pressure-low temperature (M1) metamorphism. Nevertheless, the Sm/Nd age of the same rock at ca 358 Ma appears in better agreement with the geological constraints, and thus might reflect the age of the HP event. Similar 357-352 Ma monazite U-Th-Pbtot ages are obtained from relict grains in the Axial Zone kinzigites that represent restites enclosed in migmatites. Fur thermore, monazite grains from biotite-garnet-staurolite micaschists from the outer dome envelope, and Axial Zone kinzigites, yield U-Th-Pbtot ages ranging between 340 and 320 Ma. These dates are in good agreement with previously documented zircon and monazite ages from the migmatite and anatectic granites that represent a high temperature-low pressure (M2) event. The significance of the zircon and rutile ages in the eclogites is discussed in terms of hydrothermal circulations. A crustal scale model involving a North-directed intracontinental subduction, responsible for the high pressure34 low temperature (M1) metamorphism, and coeval with km-scale S-vergent recumbent folds in the Palaeozoic non-metamorphic cover, is followed by the high temperature-low pressure (M2) event, which is coeval with the development of the Axial Zone migmatitic dome, and upright folding in the Palaeozoic non-metamorphic series.

  • middle carboniferous crustal melting in the variscan belt new insights from u th pbtot monazite and u pb zircon ages of the montagne noire Axial Zone southern french massif central
    Gondwana Research, 2010
    Co-Authors: Michel Faure, Alain Cocherie, Eugene Be Mezeme, Nicolas Charles, Philippe Rossi
    Abstract:

    Abstract In France, the Devonian–Carboniferous Variscan orogeny developed at the expense of continental crust belonging to the northern margin of Gondwana. A Visean–Serpukhovian crustal melting has been recently documented in several massifs. However, in the Montagne Noire of the Variscan French Massif Central, which is the largest area involved in this partial melting episode, the age of migmatization was not clearly settled. Eleven U–Th–Pbtot. ages on monazite and three U–Pb ages on associated zircon are reported from migmatites (La Salvetat, Ourtigas), anatectic granitoids (Laouzas, Montalet) and post-migmatitic granites (Angles, Vialais, Soulie) from the Montagne Noire Axial Zone are presented here for the first time. Migmatization and emplacement of anatectic granitoids took place around 333–326 Ma (Visean) and late granitoids emplaced around 325–318 Ma (Serpukhovian). Inherited zircons and monazite date the orthogneiss source rock of the Late Visean melts between 560 Ma and 480 Ma. In migmatites and anatectic granites, inherited crystals dominate the zircon populations. The migmatitization is the middle crust expression of a pervasive Visean crustal melting event also represented by the “Tufs anthraciferes” volcanism in the northern Massif Central. This crustal melting is widespread in the French Variscan belt, though it is restricted to the upper plate of the collision belt. A mantle input appears as a likely mechanism to release the heat necessary to trigger the melting of the Variscan middle crust at a continental scale.

  • Middle Carboniferous crustal melting in the Variscan Belt: New insights from U-Th-Pbtot. monazite and U-Pb zircon ages of the Montagne Noire Axial Zone (southern French Massif Central)
    Gondwana Research, 2010
    Co-Authors: Michel Faure, Alain Cocherie, Eugene Be Mezeme, Nicolas Charles, Philippe Rossi
    Abstract:

    In France, the Devonian-Carboniferous Variscan orogeny developed at the expense of continental crust belonging to the northern margin of Gondwana. A Visean-Serpukhovian crustal melting has been recently documented in several massifs. However, in the Montagne Noire of the Variscan French Massif Central, which is the largest area involved in this partial melting episode, the age of migmatization was not clearly settled. Eleven U-Th-Pbtot. ages on monazite and three U-Pb ages on associated zircon are reported from migmatites (La Salvetat, Ourtigas), anatectic granitoids (Laouzas, Montalet) and post-migmatitic granites (Anglès, Vialais, Soulié) from the Montagne Noire Axial Zone are presented here for the first time. Migmatization and emplacement of anatectic granitoids took place around 333-326Ma (Visean) and late granitoids emplaced around 325-318Ma (Serpukhovian). Inherited zircons and monazite date the orthogneiss source rock of the Late Visean melts between 560Ma and 480Ma. In migmatites and anatectic granites, inherited crystals dominate the zircon populations. The migmatitization is the middle crust expression of a pervasive Visean crustal melting event also represented by the "Tufs anthracifères" volcanism in the northern Massif Central. This crustal melting is widespread in the French Variscan belt, though it is restricted to the upper plate of the collision belt. A mantle input appears as a likely mechanism to release the heat necessary to trigger the melting of the Variscan middle crust at a continental scale.

  • Middle Carboniferous crustal melting in the Variscan Belt: New insights from U–Th–Pbtot. monazite and U–Pb zircon ages of the Montagne Noire Axial Zone (southern French Massif Central)
    Gondwana Research, 2010
    Co-Authors: Michel Faure, Alain Cocherie, Eugene Be Mezeme, Nicolas Charles, Philippe Rossi
    Abstract:

    Abstract In France, the Devonian–Carboniferous Variscan orogeny developed at the expense of continental crust belonging to the northern margin of Gondwana. A Visean–Serpukhovian crustal melting has been recently documented in several massifs. However, in the Montagne Noire of the Variscan French Massif Central, which is the largest area involved in this partial melting episode, the age of migmatization was not clearly settled. Eleven U–Th–Pbtot. ages on monazite and three U–Pb ages on associated zircon are reported from migmatites (La Salvetat, Ourtigas), anatectic granitoids (Laouzas, Montalet) and post-migmatitic granites (Angles, Vialais, Soulie) from the Montagne Noire Axial Zone are presented here for the first time. Migmatization and emplacement of anatectic granitoids took place around 333–326 Ma (Visean) and late granitoids emplaced around 325–318 Ma (Serpukhovian). Inherited zircons and monazite date the orthogneiss source rock of the Late Visean melts between 560 Ma and 480 Ma. In migmatites and anatectic granites, inherited crystals dominate the zircon populations. The migmatitization is the middle crust expression of a pervasive Visean crustal melting event also represented by the “Tufs anthraciferes” volcanism in the northern Massif Central. This crustal melting is widespread in the French Variscan belt, though it is restricted to the upper plate of the collision belt. A mantle input appears as a likely mechanism to release the heat necessary to trigger the melting of the Variscan middle crust at a continental scale.

Michel Faure - One of the best experts on this subject based on the ideXlab platform.

  • middle carboniferous intracontinental subduction in the outer Zone of the variscan belt montagne noire Axial Zone french massif central multimethod geochronological approach of polyphase metamorphism
    Geological Society London Special Publications, 2014
    Co-Authors: Michel Faure, Alain Cocherie, Philippe Rossi, Julien Gache, Chloe Esnault, Catherine Guerrot, Lin Wei, Li Qiuli
    Abstract:

    In the migmatitic dome of the Montagne Noire Axial Zone (Variscan French Massif Central), mafic eclogites yield zircon and rutile U-Pb SHRIMP and SIMS ages around 315-308 Ma. These "young" dates, obtained in two different laboratories, do not comply with the geological constraints available for the study area that suggest an older age of the high pressure-low temperature (M1) metamorphism. Nevertheless, the Sm/Nd age of the same rock at ca 358 Ma appears in better agreement with the geological constraints, and thus might reflect the age of the HP event. Similar 357-352 Ma monazite U-Th-Pbtot ages are obtained from relict grains in the Axial Zone kinzigites that represent restites enclosed in migmatites. Fur thermore, monazite grains from biotite-garnet-staurolite micaschists from the outer dome envelope, and Axial Zone kinzigites, yield U-Th-Pbtot ages ranging between 340 and 320 Ma. These dates are in good agreement with previously documented zircon and monazite ages from the migmatite and anatectic granites that represent a high temperature-low pressure (M2) event. The significance of the zircon and rutile ages in the eclogites is discussed in terms of hydrothermal circulations. A crustal scale model involving a North-directed intracontinental subduction, responsible for the high pressure34 low temperature (M1) metamorphism, and coeval with km-scale S-vergent recumbent folds in the Palaeozoic non-metamorphic cover, is followed by the high temperature-low pressure (M2) event, which is coeval with the development of the Axial Zone migmatitic dome, and upright folding in the Palaeozoic non-metamorphic series.

  • middle carboniferous crustal melting in the variscan belt new insights from u th pbtot monazite and u pb zircon ages of the montagne noire Axial Zone southern french massif central
    Gondwana Research, 2010
    Co-Authors: Michel Faure, Alain Cocherie, Eugene Be Mezeme, Nicolas Charles, Philippe Rossi
    Abstract:

    Abstract In France, the Devonian–Carboniferous Variscan orogeny developed at the expense of continental crust belonging to the northern margin of Gondwana. A Visean–Serpukhovian crustal melting has been recently documented in several massifs. However, in the Montagne Noire of the Variscan French Massif Central, which is the largest area involved in this partial melting episode, the age of migmatization was not clearly settled. Eleven U–Th–Pbtot. ages on monazite and three U–Pb ages on associated zircon are reported from migmatites (La Salvetat, Ourtigas), anatectic granitoids (Laouzas, Montalet) and post-migmatitic granites (Angles, Vialais, Soulie) from the Montagne Noire Axial Zone are presented here for the first time. Migmatization and emplacement of anatectic granitoids took place around 333–326 Ma (Visean) and late granitoids emplaced around 325–318 Ma (Serpukhovian). Inherited zircons and monazite date the orthogneiss source rock of the Late Visean melts between 560 Ma and 480 Ma. In migmatites and anatectic granites, inherited crystals dominate the zircon populations. The migmatitization is the middle crust expression of a pervasive Visean crustal melting event also represented by the “Tufs anthraciferes” volcanism in the northern Massif Central. This crustal melting is widespread in the French Variscan belt, though it is restricted to the upper plate of the collision belt. A mantle input appears as a likely mechanism to release the heat necessary to trigger the melting of the Variscan middle crust at a continental scale.

  • Middle Carboniferous crustal melting in the Variscan Belt: New insights from U-Th-Pbtot. monazite and U-Pb zircon ages of the Montagne Noire Axial Zone (southern French Massif Central)
    Gondwana Research, 2010
    Co-Authors: Michel Faure, Alain Cocherie, Eugene Be Mezeme, Nicolas Charles, Philippe Rossi
    Abstract:

    In France, the Devonian-Carboniferous Variscan orogeny developed at the expense of continental crust belonging to the northern margin of Gondwana. A Visean-Serpukhovian crustal melting has been recently documented in several massifs. However, in the Montagne Noire of the Variscan French Massif Central, which is the largest area involved in this partial melting episode, the age of migmatization was not clearly settled. Eleven U-Th-Pbtot. ages on monazite and three U-Pb ages on associated zircon are reported from migmatites (La Salvetat, Ourtigas), anatectic granitoids (Laouzas, Montalet) and post-migmatitic granites (Anglès, Vialais, Soulié) from the Montagne Noire Axial Zone are presented here for the first time. Migmatization and emplacement of anatectic granitoids took place around 333-326Ma (Visean) and late granitoids emplaced around 325-318Ma (Serpukhovian). Inherited zircons and monazite date the orthogneiss source rock of the Late Visean melts between 560Ma and 480Ma. In migmatites and anatectic granites, inherited crystals dominate the zircon populations. The migmatitization is the middle crust expression of a pervasive Visean crustal melting event also represented by the "Tufs anthracifères" volcanism in the northern Massif Central. This crustal melting is widespread in the French Variscan belt, though it is restricted to the upper plate of the collision belt. A mantle input appears as a likely mechanism to release the heat necessary to trigger the melting of the Variscan middle crust at a continental scale.

  • Middle Carboniferous crustal melting in the Variscan Belt: New insights from U–Th–Pbtot. monazite and U–Pb zircon ages of the Montagne Noire Axial Zone (southern French Massif Central)
    Gondwana Research, 2010
    Co-Authors: Michel Faure, Alain Cocherie, Eugene Be Mezeme, Nicolas Charles, Philippe Rossi
    Abstract:

    Abstract In France, the Devonian–Carboniferous Variscan orogeny developed at the expense of continental crust belonging to the northern margin of Gondwana. A Visean–Serpukhovian crustal melting has been recently documented in several massifs. However, in the Montagne Noire of the Variscan French Massif Central, which is the largest area involved in this partial melting episode, the age of migmatization was not clearly settled. Eleven U–Th–Pbtot. ages on monazite and three U–Pb ages on associated zircon are reported from migmatites (La Salvetat, Ourtigas), anatectic granitoids (Laouzas, Montalet) and post-migmatitic granites (Angles, Vialais, Soulie) from the Montagne Noire Axial Zone are presented here for the first time. Migmatization and emplacement of anatectic granitoids took place around 333–326 Ma (Visean) and late granitoids emplaced around 325–318 Ma (Serpukhovian). Inherited zircons and monazite date the orthogneiss source rock of the Late Visean melts between 560 Ma and 480 Ma. In migmatites and anatectic granites, inherited crystals dominate the zircon populations. The migmatitization is the middle crust expression of a pervasive Visean crustal melting event also represented by the “Tufs anthraciferes” volcanism in the northern Massif Central. This crustal melting is widespread in the French Variscan belt, though it is restricted to the upper plate of the collision belt. A mantle input appears as a likely mechanism to release the heat necessary to trigger the melting of the Variscan middle crust at a continental scale.

  • The emplacement of the Montagne Noire Axial Zone (French Massif Central): New insights from petro-textural, geochronological and AMS studies
    2008
    Co-Authors: Nicolas Charles, Michel Faure, Yan Chen
    Abstract:

    In the southern French Massif Central, the Montagne Noire Axial Zone is a NE-SW elongated granitic-migmatitic dome surrounded by recumbently folded Palaeozoic sedimentary series with a southern vergence. From rim to core, the Axial Zone consists of micaschist, gneiss, augen orthogneiss, cordierite migmatite, and anatectic granites (Laouzas, Montalet). Syn- to late kinematic granitoids intrude the dome. The relative succession of events in Montagne Noire: 1-recumbent folding, 2-doming and 3-post-migmatitic granitoids intrusion is widely acknowledged. Conversely, the tectonic setting of the doming is disputed. The proposed models do not take into account the granitic and migmatitic structures, geochronology and dome core structure. Therefore, petro-textural and Magnetic Susceptibility Anisotropy studies and new monazite U-Th/Pb datings have been carried out in the Montagne Noire Axial Zone. The Montalet granite (333±4 Ma) is coeval with migmatization, and the Soulié granite (318±4 Ma) marks dome intrusion. In the dome Axial Zone rocks, magmatic, late-magmatic, tectonic and metamorphic textures have been recognized. Magnetic mineralogical study indicates that biotite is the main carrier of the magnetic susceptibility in granitic and migmatitic rocks, and that cordierite does not influence vectors directions. The attitude of the magnetic foliation complies with the preferred orientation of biotite, schlierens, enclaves and with migmatitic foliation observed in the field. The AMS fabric confirms the elliptical shape of the Axial Zone inferred from the migmatitic and gneissic envelope. The southward dipping foliation identified in both flanks is in agreement with an asymmetric dome. Moreover, the magnetic lineations exhibit a contrasting pattern with a dominant NE-SW trend, and a N-S one as well. The AMS features are in agreement with a diapiric component for the migmatite ascent. A model involving diapirism coeval with anticlinal stacking followed by extension discussed.

Alain Cocherie - One of the best experts on this subject based on the ideXlab platform.

  • middle carboniferous intracontinental subduction in the outer Zone of the variscan belt montagne noire Axial Zone french massif central multimethod geochronological approach of polyphase metamorphism
    Geological Society London Special Publications, 2014
    Co-Authors: Michel Faure, Alain Cocherie, Philippe Rossi, Julien Gache, Chloe Esnault, Catherine Guerrot, Lin Wei, Li Qiuli
    Abstract:

    In the migmatitic dome of the Montagne Noire Axial Zone (Variscan French Massif Central), mafic eclogites yield zircon and rutile U-Pb SHRIMP and SIMS ages around 315-308 Ma. These "young" dates, obtained in two different laboratories, do not comply with the geological constraints available for the study area that suggest an older age of the high pressure-low temperature (M1) metamorphism. Nevertheless, the Sm/Nd age of the same rock at ca 358 Ma appears in better agreement with the geological constraints, and thus might reflect the age of the HP event. Similar 357-352 Ma monazite U-Th-Pbtot ages are obtained from relict grains in the Axial Zone kinzigites that represent restites enclosed in migmatites. Fur thermore, monazite grains from biotite-garnet-staurolite micaschists from the outer dome envelope, and Axial Zone kinzigites, yield U-Th-Pbtot ages ranging between 340 and 320 Ma. These dates are in good agreement with previously documented zircon and monazite ages from the migmatite and anatectic granites that represent a high temperature-low pressure (M2) event. The significance of the zircon and rutile ages in the eclogites is discussed in terms of hydrothermal circulations. A crustal scale model involving a North-directed intracontinental subduction, responsible for the high pressure34 low temperature (M1) metamorphism, and coeval with km-scale S-vergent recumbent folds in the Palaeozoic non-metamorphic cover, is followed by the high temperature-low pressure (M2) event, which is coeval with the development of the Axial Zone migmatitic dome, and upright folding in the Palaeozoic non-metamorphic series.

  • middle carboniferous crustal melting in the variscan belt new insights from u th pbtot monazite and u pb zircon ages of the montagne noire Axial Zone southern french massif central
    Gondwana Research, 2010
    Co-Authors: Michel Faure, Alain Cocherie, Eugene Be Mezeme, Nicolas Charles, Philippe Rossi
    Abstract:

    Abstract In France, the Devonian–Carboniferous Variscan orogeny developed at the expense of continental crust belonging to the northern margin of Gondwana. A Visean–Serpukhovian crustal melting has been recently documented in several massifs. However, in the Montagne Noire of the Variscan French Massif Central, which is the largest area involved in this partial melting episode, the age of migmatization was not clearly settled. Eleven U–Th–Pbtot. ages on monazite and three U–Pb ages on associated zircon are reported from migmatites (La Salvetat, Ourtigas), anatectic granitoids (Laouzas, Montalet) and post-migmatitic granites (Angles, Vialais, Soulie) from the Montagne Noire Axial Zone are presented here for the first time. Migmatization and emplacement of anatectic granitoids took place around 333–326 Ma (Visean) and late granitoids emplaced around 325–318 Ma (Serpukhovian). Inherited zircons and monazite date the orthogneiss source rock of the Late Visean melts between 560 Ma and 480 Ma. In migmatites and anatectic granites, inherited crystals dominate the zircon populations. The migmatitization is the middle crust expression of a pervasive Visean crustal melting event also represented by the “Tufs anthraciferes” volcanism in the northern Massif Central. This crustal melting is widespread in the French Variscan belt, though it is restricted to the upper plate of the collision belt. A mantle input appears as a likely mechanism to release the heat necessary to trigger the melting of the Variscan middle crust at a continental scale.

  • Middle Carboniferous crustal melting in the Variscan Belt: New insights from U-Th-Pbtot. monazite and U-Pb zircon ages of the Montagne Noire Axial Zone (southern French Massif Central)
    Gondwana Research, 2010
    Co-Authors: Michel Faure, Alain Cocherie, Eugene Be Mezeme, Nicolas Charles, Philippe Rossi
    Abstract:

    In France, the Devonian-Carboniferous Variscan orogeny developed at the expense of continental crust belonging to the northern margin of Gondwana. A Visean-Serpukhovian crustal melting has been recently documented in several massifs. However, in the Montagne Noire of the Variscan French Massif Central, which is the largest area involved in this partial melting episode, the age of migmatization was not clearly settled. Eleven U-Th-Pbtot. ages on monazite and three U-Pb ages on associated zircon are reported from migmatites (La Salvetat, Ourtigas), anatectic granitoids (Laouzas, Montalet) and post-migmatitic granites (Anglès, Vialais, Soulié) from the Montagne Noire Axial Zone are presented here for the first time. Migmatization and emplacement of anatectic granitoids took place around 333-326Ma (Visean) and late granitoids emplaced around 325-318Ma (Serpukhovian). Inherited zircons and monazite date the orthogneiss source rock of the Late Visean melts between 560Ma and 480Ma. In migmatites and anatectic granites, inherited crystals dominate the zircon populations. The migmatitization is the middle crust expression of a pervasive Visean crustal melting event also represented by the "Tufs anthracifères" volcanism in the northern Massif Central. This crustal melting is widespread in the French Variscan belt, though it is restricted to the upper plate of the collision belt. A mantle input appears as a likely mechanism to release the heat necessary to trigger the melting of the Variscan middle crust at a continental scale.

  • Middle Carboniferous crustal melting in the Variscan Belt: New insights from U–Th–Pbtot. monazite and U–Pb zircon ages of the Montagne Noire Axial Zone (southern French Massif Central)
    Gondwana Research, 2010
    Co-Authors: Michel Faure, Alain Cocherie, Eugene Be Mezeme, Nicolas Charles, Philippe Rossi
    Abstract:

    Abstract In France, the Devonian–Carboniferous Variscan orogeny developed at the expense of continental crust belonging to the northern margin of Gondwana. A Visean–Serpukhovian crustal melting has been recently documented in several massifs. However, in the Montagne Noire of the Variscan French Massif Central, which is the largest area involved in this partial melting episode, the age of migmatization was not clearly settled. Eleven U–Th–Pbtot. ages on monazite and three U–Pb ages on associated zircon are reported from migmatites (La Salvetat, Ourtigas), anatectic granitoids (Laouzas, Montalet) and post-migmatitic granites (Angles, Vialais, Soulie) from the Montagne Noire Axial Zone are presented here for the first time. Migmatization and emplacement of anatectic granitoids took place around 333–326 Ma (Visean) and late granitoids emplaced around 325–318 Ma (Serpukhovian). Inherited zircons and monazite date the orthogneiss source rock of the Late Visean melts between 560 Ma and 480 Ma. In migmatites and anatectic granites, inherited crystals dominate the zircon populations. The migmatitization is the middle crust expression of a pervasive Visean crustal melting event also represented by the “Tufs anthraciferes” volcanism in the northern Massif Central. This crustal melting is widespread in the French Variscan belt, though it is restricted to the upper plate of the collision belt. A mantle input appears as a likely mechanism to release the heat necessary to trigger the melting of the Variscan middle crust at a continental scale.

Massimiliano Zattin - One of the best experts on this subject based on the ideXlab platform.

  • thermal maturity of the Axial Zone of the southern apennines fold and thrust belt italy from multiple organic and inorganic indicators
    Terra Nova, 2005
    Co-Authors: Sveva Corrado, Luca Aldega, P Di Leo, C. Giampaolo, Chiara Invernizzi, Stefano Mazzoli, Massimiliano Zattin
    Abstract:

    The reconstruction of the thermal history of folded and thrust units is crucial to define the pattern of tectonic loading and the time-space evolution of an orogen where tectonic exhumation processes occurred at shallow crustal levels. In the present study, a well-constrained reconstruction of the thermal maturity in the Axial Zone of the southern Apennines has been achieved by the combined use of different thermal indicators in diagenesis. The major results are: (i) documentation of a jump in thermal maturity from the Apenninic Platform derived tectonic unit (from immature to early mature stages of hydrocarbon maturation) to the Lagonegro Basin derived tectonic units (late diagenetic Zone); (ii) documentation of along-strike slighter variations in the Lagonegro units, concerning thermal maturity (thus maximum burial temperatures). This can be related to changes in amounts of tectonic burial and erosion/exhumation because of the lack of cylindricity of contractional structures; (iii) recognition of an independent thermal evolution of the allochthonous chain compared with the Apulian Platform tectonic unit with Mt Alpi area (in the late mature stage of hydrocarbon generation) interpreted as a sector of localized, intense exhumation within the External Zone of the orogen.

  • Thermal maturity of the Axial Zone of the southern Apennines fold‐and‐thrust belt (Italy) from multiple organic and inorganic indicators
    Terra Nova, 2005
    Co-Authors: Sveva Corrado, Luca Aldega, P Di Leo, C. Giampaolo, Chiara Invernizzi, Stefano Mazzoli, Massimiliano Zattin
    Abstract:

    The reconstruction of the thermal history of folded and thrust units is crucial to define the pattern of tectonic loading and the time-space evolution of an orogen where tectonic exhumation processes occurred at shallow crustal levels. In the present study, a well-constrained reconstruction of the thermal maturity in the Axial Zone of the southern Apennines has been achieved by the combined use of different thermal indicators in diagenesis. The major results are: (i) documentation of a jump in thermal maturity from the Apenninic Platform derived tectonic unit (from immature to early mature stages of hydrocarbon maturation) to the Lagonegro Basin derived tectonic units (late diagenetic Zone); (ii) documentation of along-strike slighter variations in the Lagonegro units, concerning thermal maturity (thus maximum burial temperatures). This can be related to changes in amounts of tectonic burial and erosion/exhumation because of the lack of cylindricity of contractional structures; (iii) recognition of an independent thermal evolution of the allochthonous chain compared with the Apulian Platform tectonic unit with Mt Alpi area (in the late mature stage of hydrocarbon generation) interpreted as a sector of localized, intense exhumation within the External Zone of the orogen.

Nicolas Charles - One of the best experts on this subject based on the ideXlab platform.

  • middle carboniferous crustal melting in the variscan belt new insights from u th pbtot monazite and u pb zircon ages of the montagne noire Axial Zone southern french massif central
    Gondwana Research, 2010
    Co-Authors: Michel Faure, Alain Cocherie, Eugene Be Mezeme, Nicolas Charles, Philippe Rossi
    Abstract:

    Abstract In France, the Devonian–Carboniferous Variscan orogeny developed at the expense of continental crust belonging to the northern margin of Gondwana. A Visean–Serpukhovian crustal melting has been recently documented in several massifs. However, in the Montagne Noire of the Variscan French Massif Central, which is the largest area involved in this partial melting episode, the age of migmatization was not clearly settled. Eleven U–Th–Pbtot. ages on monazite and three U–Pb ages on associated zircon are reported from migmatites (La Salvetat, Ourtigas), anatectic granitoids (Laouzas, Montalet) and post-migmatitic granites (Angles, Vialais, Soulie) from the Montagne Noire Axial Zone are presented here for the first time. Migmatization and emplacement of anatectic granitoids took place around 333–326 Ma (Visean) and late granitoids emplaced around 325–318 Ma (Serpukhovian). Inherited zircons and monazite date the orthogneiss source rock of the Late Visean melts between 560 Ma and 480 Ma. In migmatites and anatectic granites, inherited crystals dominate the zircon populations. The migmatitization is the middle crust expression of a pervasive Visean crustal melting event also represented by the “Tufs anthraciferes” volcanism in the northern Massif Central. This crustal melting is widespread in the French Variscan belt, though it is restricted to the upper plate of the collision belt. A mantle input appears as a likely mechanism to release the heat necessary to trigger the melting of the Variscan middle crust at a continental scale.

  • Middle Carboniferous crustal melting in the Variscan Belt: New insights from U-Th-Pbtot. monazite and U-Pb zircon ages of the Montagne Noire Axial Zone (southern French Massif Central)
    Gondwana Research, 2010
    Co-Authors: Michel Faure, Alain Cocherie, Eugene Be Mezeme, Nicolas Charles, Philippe Rossi
    Abstract:

    In France, the Devonian-Carboniferous Variscan orogeny developed at the expense of continental crust belonging to the northern margin of Gondwana. A Visean-Serpukhovian crustal melting has been recently documented in several massifs. However, in the Montagne Noire of the Variscan French Massif Central, which is the largest area involved in this partial melting episode, the age of migmatization was not clearly settled. Eleven U-Th-Pbtot. ages on monazite and three U-Pb ages on associated zircon are reported from migmatites (La Salvetat, Ourtigas), anatectic granitoids (Laouzas, Montalet) and post-migmatitic granites (Anglès, Vialais, Soulié) from the Montagne Noire Axial Zone are presented here for the first time. Migmatization and emplacement of anatectic granitoids took place around 333-326Ma (Visean) and late granitoids emplaced around 325-318Ma (Serpukhovian). Inherited zircons and monazite date the orthogneiss source rock of the Late Visean melts between 560Ma and 480Ma. In migmatites and anatectic granites, inherited crystals dominate the zircon populations. The migmatitization is the middle crust expression of a pervasive Visean crustal melting event also represented by the "Tufs anthracifères" volcanism in the northern Massif Central. This crustal melting is widespread in the French Variscan belt, though it is restricted to the upper plate of the collision belt. A mantle input appears as a likely mechanism to release the heat necessary to trigger the melting of the Variscan middle crust at a continental scale.

  • Middle Carboniferous crustal melting in the Variscan Belt: New insights from U–Th–Pbtot. monazite and U–Pb zircon ages of the Montagne Noire Axial Zone (southern French Massif Central)
    Gondwana Research, 2010
    Co-Authors: Michel Faure, Alain Cocherie, Eugene Be Mezeme, Nicolas Charles, Philippe Rossi
    Abstract:

    Abstract In France, the Devonian–Carboniferous Variscan orogeny developed at the expense of continental crust belonging to the northern margin of Gondwana. A Visean–Serpukhovian crustal melting has been recently documented in several massifs. However, in the Montagne Noire of the Variscan French Massif Central, which is the largest area involved in this partial melting episode, the age of migmatization was not clearly settled. Eleven U–Th–Pbtot. ages on monazite and three U–Pb ages on associated zircon are reported from migmatites (La Salvetat, Ourtigas), anatectic granitoids (Laouzas, Montalet) and post-migmatitic granites (Angles, Vialais, Soulie) from the Montagne Noire Axial Zone are presented here for the first time. Migmatization and emplacement of anatectic granitoids took place around 333–326 Ma (Visean) and late granitoids emplaced around 325–318 Ma (Serpukhovian). Inherited zircons and monazite date the orthogneiss source rock of the Late Visean melts between 560 Ma and 480 Ma. In migmatites and anatectic granites, inherited crystals dominate the zircon populations. The migmatitization is the middle crust expression of a pervasive Visean crustal melting event also represented by the “Tufs anthraciferes” volcanism in the northern Massif Central. This crustal melting is widespread in the French Variscan belt, though it is restricted to the upper plate of the collision belt. A mantle input appears as a likely mechanism to release the heat necessary to trigger the melting of the Variscan middle crust at a continental scale.

  • The emplacement of the Montagne Noire Axial Zone (French Massif Central): New insights from petro-textural, geochronological and AMS studies
    2008
    Co-Authors: Nicolas Charles, Michel Faure, Yan Chen
    Abstract:

    In the southern French Massif Central, the Montagne Noire Axial Zone is a NE-SW elongated granitic-migmatitic dome surrounded by recumbently folded Palaeozoic sedimentary series with a southern vergence. From rim to core, the Axial Zone consists of micaschist, gneiss, augen orthogneiss, cordierite migmatite, and anatectic granites (Laouzas, Montalet). Syn- to late kinematic granitoids intrude the dome. The relative succession of events in Montagne Noire: 1-recumbent folding, 2-doming and 3-post-migmatitic granitoids intrusion is widely acknowledged. Conversely, the tectonic setting of the doming is disputed. The proposed models do not take into account the granitic and migmatitic structures, geochronology and dome core structure. Therefore, petro-textural and Magnetic Susceptibility Anisotropy studies and new monazite U-Th/Pb datings have been carried out in the Montagne Noire Axial Zone. The Montalet granite (333±4 Ma) is coeval with migmatization, and the Soulié granite (318±4 Ma) marks dome intrusion. In the dome Axial Zone rocks, magmatic, late-magmatic, tectonic and metamorphic textures have been recognized. Magnetic mineralogical study indicates that biotite is the main carrier of the magnetic susceptibility in granitic and migmatitic rocks, and that cordierite does not influence vectors directions. The attitude of the magnetic foliation complies with the preferred orientation of biotite, schlierens, enclaves and with migmatitic foliation observed in the field. The AMS fabric confirms the elliptical shape of the Axial Zone inferred from the migmatitic and gneissic envelope. The southward dipping foliation identified in both flanks is in agreement with an asymmetric dome. Moreover, the magnetic lineations exhibit a contrasting pattern with a dominant NE-SW trend, and a N-S one as well. The AMS features are in agreement with a diapiric component for the migmatite ascent. A model involving diapirism coeval with anticlinal stacking followed by extension discussed.

  • The emplacement of the Montagne Noire Axial Zone (French Massif Central): New insights from petro-textural, geochronological and AMS studies
    2008
    Co-Authors: Nicolas Charles, Michel Faure, Yan Chen
    Abstract:

    In the southern French Massif Central, the Montagne Noire Axial Zone is a NE-SW elongated granitic-migmatitic dome surrounded by recumbently folded Palaeozoic sedimentary series with a southern vergence. From rim to core, the Axial Zone consists of micaschist, gneiss, augen orthogneiss, cordierite migmatite, and anatectic granites (Laouzas, Montalet). Syn- to late kinematic granitoids intrude the dome. The relative succession of events in Montagne Noire: 1-recumbent folding, 2-doming and 3-post-migmatitic granitoids intrusion is widely acknowledged. Conversely, the tectonic setting of the doming is disputed. The proposed models do not take into account the granitic and migmatitic structures, geochronology and dome core structure. Therefore, petro-textural and Magnetic Susceptibility Anisotropy studies and new monazite U-Th/Pb datings have been carried out in the Montagne Noire Axial Zone. The Montalet granite (333±4 Ma) is coeval with migmatization, and the Soulie granite (318±4 Ma) marks dome intrusion. In the dome Axial Zone rocks, magmatic, late-magmatic, tectonic and metamorphic textures have been recognized. Magnetic mineralogical study indicates that biotite is the main carrier of the magnetic susceptibility in granitic and migmatitic rocks, and that cordierite does not influence vectors directions. The attitude of the magnetic foliation complies with the preferred orientation of biotite, schlierens, enclaves and with migmatitic foliation observed in the field. The AMS fabric confirms the elliptical shape of the Axial Zone inferred from the migmatitic and gneissic envelope. The southward dipping foliation identified in both flanks is in agreement with an asymmetric dome. Moreover, the magnetic lineations exhibit a contrasting pattern with a dominant NE-SW trend, and a N-S one as well. The AMS features are in agreement with a diapiric component for the migmatite ascent. A model involving diapirism coeval with anticlinal stacking followed by extension discussed.