Late‐Orogenic Evolution of the Southern European Variscan Belt Constrained by Fabric Analysis and Dating of the Camarat Granitic Complex and Coeval Felsic Dykes (Maures–Tanneron Massif, SE France)

The Camarat Granitic Complex (CGC), emplaced in the migmatitic Internal Zone of the Maures–Tanneron Massif (MTM), SE Variscides, consists of the Gigaro granodiorite and the composite Camarat granite. U‐Pb dating of the latter gives crystallization ages of 304.5 ± 3.3 Ma (zircon date) and 303.5 ± 4.0 Ma (monazite date). Two representatives of late felsic dykes cutting across the MTM Internal Zone have 39Ar/40Ar muscovite ages of 302.43 ± 2.62 Ma and 298.11 ± 2.38. Magmatic lineations revealed by anisotropy of magnetic susceptibility (AMS) measurements and image analysis, aplite dykes, dyke‐like bodies of cordierite microgranite and joints in the Camarat granite, as well as the late dykes all have orientations consistent with subhorizontal, NNE‐SSW‐trending lineations in the migmatitic country rocks representing the stretching direction of a late‐Variscan transpression phase (D3). The CGC and the late dykes are therefore witness to a thermal event that affected the MTM between ∼305 and ∼298 Ma (late Pennsylvanian–earliest Permian times), at the end of D3 which initiated at ∼325 Ma. Grabens related to post‐Variscan, Permian rifting (D4 phase), which cut across the MTM are WNW‐ESE‐trending, indicating a NNE‐SSW direction of extension, parallel to the previous (D3) lateral horizontal flow. The present results and a comparison with AMS data published for the Corsica–Sardinia Batholith reveal that evolution in the SE Variscides from Devonian–early Carboniferous contraction to Permian extension, through late Carboniferous transpression is characterized by the persistence of a ca. N‐S stretching direction, supporting a strong horizontal, orogen‐parallel crustal flow.

[1]  M. Corsini,et al.  A vestige of an Ediacaran magmatic arc in southeast France and its significance for the northern Gondwana margin , 2022, International Journal of Earth Sciences.

[2]  A. Langone,et al.  HTLP metamorphism and fluid‐fluxed melting during multistage anatexis of continental crust (N Sardinia, Italy) , 2022, Journal of Metamorphic Geology.

[3]  K. Schulmann,et al.  The Mid-Variscan Allochthon: Keys from correlation, partial retrodeformation and plate-tectonic reconstruction to unlock the geometry of a non-cylindrical belt , 2021 .

[4]  S. Iaccarino,et al.  Timing and kinematics of flow in a transpressive dextral shear zone, Maures Massif (Southern France) , 2020, International Journal of Earth Sciences.

[5]  O. Laurent,et al.  Evaluating the reliability of U–Pb laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) carbonate geochronology: matrix issues and a potential calcite validation reference material , 2020 .

[6]  M. Stipp,et al.  Polyphase magmatic pulses along the Northern Gondwana margin: U-Pb zircon geochronology from gneiss domes of the Pyrenees , 2020 .

[7]  V. Gardien,et al.  Flow of partially molten crust controlling construction, growth and collapse of the Variscan orogenic belt: the geologic record of the French Massif Central , 2020, BSGF - Earth Sciences Bulletin.

[8]  L. Jolivet,et al.  Fast dismantling of a mountain belt by mantle flow: Late-orogenic evolution of Pyrenees and Liguro-Provençal rifting , 2020, Tectonophysics.

[9]  J. Moyen,et al.  Detrital zircon U–Pb–Hf systematics of Ediacaran metasediments from the French Massif Central: Consequences for the crustal evolution of the north Gondwana margin , 2019, Precambrian Research.

[10]  P. Vermeesch IsoplotR: A free and open toolbox for geochronology , 2018, Geoscience Frontiers.

[11]  R. Romer,et al.  The pre-orogenic detrital zircon record of the Peri-Gondwanan crust , 2018, Geological Magazine.

[12]  K. Schulmann,et al.  Late Palaeozoic palaeomagnetic and tectonic constraints for amalgamation of Pangea supercontinent in the European Variscan belt , 2018 .

[13]  Hervé Diot,et al.  Pluton construction and deformation in the Sveconorwegian crust of SW Norway: Magnetic fabric and U-Pb geochronology of the Kleivan and Sjelset granitic complexes , 2018 .

[14]  A. Langone,et al.  Zircon U‐Pb Dating of a Lower Crustal Shear Zone: A Case Study From the Northern Sector of the Ivrea‐Verbano Zone (Val Cannobina, Italy) , 2018 .

[15]  M. Corsini,et al.  Crustal exhumation during ongoing compression in the Variscan Maures-Tanneron Massif, France-Geological and thermo-mechanical aspects , 2016, Tectonophysics.

[16]  T. Torsvik,et al.  The Palaeozoic Variscan oceans revisited , 2017 .

[17]  P. Olivier,et al.  Anisotropy of magnetic susceptibility of the Pyrenean granites , 2017 .

[18]  V. Gardien,et al.  Protracted, coeval crust and mantle melting during Variscan late-orogenic evolution: U–Pb dating in the eastern French Massif Central , 2017, International Journal of Earth Sciences.

[19]  A. Funedda,et al.  The geological map of Sardinia (Italy) at 1:250,000 scale , 2016 .

[20]  J. Bowring,et al.  Community‐Derived Standards for LA‐ICP‐MS U‐(Th‐)Pb Geochronology – Uncertainty Propagation, Age Interpretation and Data Reporting , 2016 .

[21]  F. Corfu,et al.  An assessment of monazite from the Itambé pegmatite district for use as U-Pb isotope reference material for microanalysis and implications for the origin of the ``Moacyr'' monazite , 2016 .

[22]  L. Lecca,et al.  NOTE ILLUSTRATIVE DELLA CARTA GEOLOGICA D'ITALIA ALLA SCALA 1:50.000, FOGLIO 528 ORISTANO , 2016 .

[23]  L. Casini,et al.  Evolution of the Corsica–Sardinia Batholith and late-orogenic shearing of the Variscides , 2015 .

[24]  V. Gardien,et al.  Variscan crustal thickening in the Maures-Tanneron massif (South Variscan belt, France): new in situ monazite U-Th-Pb chemical dating of high-grade rocks , 2015 .

[25]  A. Cocherie,et al.  Evidence in Variscan Corsica of a brief and voluminous Late Carboniferous to Early Permian volcanic-plutonic event contemporaneous with a high-temperature/low-pressure metamorphic peak in the lower crust , 2015 .

[26]  M. Maino,et al.  Structural map of Variscan northern Sardinia (Italy) , 2015 .

[27]  Wei Lin,et al.  From crustal anatexis to mantle melting in the Variscan orogen of Corsica (France): SIMS U-Pb zircon age constraints , 2014 .

[28]  D. Dunlop High-temperature susceptibility of magnetite: a new pseudo-single-domain effect , 2014 .

[29]  M. Schmitz,et al.  EOCENE ZIRCON REFERENCE MATERIAL FOR MICROANALYSIS OF U-Th-Pb ISOTOPES AND TRACE ELEMENTS , 2014 .

[30]  A. Gerdes,et al.  The East Variscan Shear Zone: Geochronological constraints from the Capo Ferro area (NE Sardinia, Italy) , 2014 .

[31]  L. Casini,et al.  Early Permian 90° clockwise rotation of the Maures–Estérel–Corsica–Sardinia block confirmed by new palaeomagnetic data and followed by a Triassic 60° clockwise rotation , 2014 .

[32]  M. Corsini,et al.  Thermal and mechanical evolution of an orogenic wedge during Variscan collision: an example in the Maures–Tanneron Massif (SE France) , 2014 .

[33]  MathewDomeier Plate tectonics in the late Paleozoic , 2014 .

[34]  J. Liégeois,et al.  The fast evolution of a crustal hot zone at the end of a transpressional regime: The Saint-Tropez peninsula granites and related dykes (Maures Massif, SE France) , 2013 .

[35]  B. Kamber,et al.  VizualAge: A Novel Approach to Laser Ablation ICP‐MS U‐Pb Geochronology Data Reduction , 2012 .

[36]  M. Tiepolo,et al.  Emplacement of the Arzachena Pluton (Corsica–Sardinia Batholith) and the geodynamics of incoming Pangaea , 2012 .

[37]  R. Romer,et al.  Dating rock deformation with monazite: The impact of dissolution precipitation creep , 2012 .

[38]  M. Tiepolo,et al.  Geochronological constraints on post‐collisional shear zones in the Variscides of Sardinia (Italy) , 2012 .

[39]  R. Wirth,et al.  Fluid-mediated partial alteration in monazite: the role of coupled dissolution–reprecipitation in element redistribution and mass transfer , 2011 .

[40]  A. Ronchi,et al.  Permian continental basins in the Southern Alps (Italy) and peri-mediterranean correlations , 2011, International Journal of Earth Sciences.

[41]  M. Tiepolo,et al.  Miocene to Messinian deformation and hydrothermal activity in a pre-Alpine basement massif of the French western Alps: new U-Th-Pb and argon ages from the Lauzière massif , 2010 .

[42]  M. Chichorro,et al.  Relative timing of transcurrent displacements in northern Gondwana: U–Pb laser ablation ICP-MS zircon and monazite geochronology of gneisses and sheared granites from the western Iberian Massif (Portugal) , 2010 .

[43]  M. Corsini,et al.  Exhumation processes during post-collisional stage in the Variscan belt revealed by detailed 40Ar/39Ar study (Tanneron Massif, SE France) , 2010 .

[44]  J. Hellstrom,et al.  Improved laser ablation U‐Pb zircon geochronology through robust downhole fractionation correction , 2010 .

[45]  R. Carosi,et al.  Kinematics and vorticity of flow associated with post-collisional oblique transpression in the Variscan Inner Zone of northern Sardinia (Italy) , 2009 .

[46]  M. Corsini,et al.  Metamorphic and structural evolution of the Maures-Tanneron massif (SE Variscan chain): evidence of doming along a transpressional margin , 2009 .

[47]  D. Marquer,et al.  Famenno-Carboniferous (370-320 Ma) strike slip tectonics monitored by syn-kinematic plutons in the French Variscan belt (Massif Armoricain and French Massif Central) , 2009 .

[48]  K. Benn Anisotropy of magnetic susceptibility fabrics in syntectonic plutons as tectonic strain markers: the example of the Canso pluton, Meguma Terrane, Nova Scotia , 2009, Earth and Environmental Science Transactions of the Royal Society of Edinburgh.

[49]  P. Ledru,et al.  A review of the pre-Permian geology of the Variscan French Massif Central , 2009 .

[50]  M. Corsini,et al.  Late evolution of the southern European Variscan belt: Exhumation of the lower crust in a context of oblique convergence , 2009 .

[51]  S. Guillot,et al.  Paleozoic evolution of the External Crystalline Massifs of the Western Alps , 2009 .

[52]  M. Durand Permian to Triassic continental successions in southern Provence (France); an overview , 2008 .

[53]  E. Carminati,et al.  Exhumation of a Variscan orogenic complex: insights into the composite granulitic–amphibolitic metamorphic basement of south‐east Corsica (France) , 2008 .

[54]  M. Whitehouse,et al.  Plesovice zircon : A new natural reference material for U-Pb and Hf isotopic microanalysis , 2008 .

[55]  U. Schärer,et al.  Variscan evolution of the Tanneron massif, SE France, examined through U–Pb monazite ages , 2008, Journal of the Geological Society.

[56]  C. Villaseca,et al.  SHRIMP U–Pb zircon dating of anatexis in high-grade migmatite complexes of Central Spain: implications in the Hercynian evolution of Central Iberia , 2008 .

[57]  S. Guillot,et al.  Orogen-parallel flow during continental convergence: Numerical experiments and Archean field examples , 2007 .

[58]  David S. Jones,et al.  Miocene rotation of Sardinia: New paleomagnetic and geochronological constraints and geodynamic implications , 2007 .

[59]  M. Tiepolo,et al.  High resolution (5 μm) U–Th–Pb isotope dating of monazite with excimer laser ablation (ELA)-ICPMS , 2007 .

[60]  M. Tiepolo,et al.  Origin and timing of the post-Variscan gabbro–granite complex of Porto (Western Corsica) , 2007 .

[61]  D. Dunlop,et al.  Magnetizations in Rocks and Minerals , 2007 .

[62]  E. Petrovský,et al.  On determination of the Curie point from thermomagnetic curves , 2006 .

[63]  J. Severinghaus,et al.  A redetermination of the isotopic abundances of atmospheric Ar , 2006 .

[64]  D. Rancourt,et al.  Magnetism of biotite crystals , 2006 .

[65]  J. Brun,et al.  Crustal thickening and lateral flow during compression of hot lithospheres, with particular reference to Precambrian times , 2006 .

[66]  G. Martelet,et al.  Structure of late Variscan Millevaches leucogranite massif in the French Massif Central: AMS and gravity modelling results , 2006 .

[67]  C. Guerrot,et al.  Comparative use of TIMS and SHRIMP for U–Pb zircon dating of A-type granites and mafic tholeiitic layered complexes and dykes from the Corsican Batholith (France) , 2005 .

[68]  J. Bellot The Palaeozoic evolution of the Maures massif (France) and its potential correlation with others areas of the Variscan belt: a review , 2005 .

[69]  P. Launeau,et al.  Determination of fabric and strain ellipsoids from measured sectional ellipses—implementation and applications , 2005 .

[70]  P. Rochette,et al.  Magnetic fabric of granitoids from Southern Corsica and Northern Sardinia and implications for Late Hercynian tectonic setting , 2004, Journal of the Geological Society.

[71]  M. Jackson,et al.  Anisotropy of magnetic susceptibility (AMS): magnetic petrofabrics of deformed rocks , 2004, Geological Society, London, Special Publications.

[72]  R. Korsch,et al.  TEMORA 1: a new zircon standard for Phanerozoic U–Pb geochronology , 2003 .

[73]  C. Pin,et al.  Episodic and short-lived granitic pulses in a post-collisional setting: evidence from precise U–Pb zircon dating through a crustal cross-section in Corsica , 2003 .

[74]  P. Robion,et al.  Anisotropy of magnetic susceptibility of heated rocks , 2003 .

[75]  C. Laverne,et al.  Evidence for two burial/exhumation stages during the evolution of the Variscan belt, as exemplified by P–T–t–d paths of metabasites in distinct allochthonous units of the Maures massif (SE France) , 2003 .

[76]  A. Moro,et al.  Late to post-hercynian dyke activity in the Sardinia-Corsica Domain : A transition from orogenic calc-alkaline to anorogenic alkaline magmatism , 2003 .

[77]  C. Guerrot,et al.  Datation U-Pb sur zircons à 548 Ma de leptynites des Maures centrales. Signification géodynamique des complexes leptyno-amphibolitiques de l’Europe varisque , 2003 .

[78]  R. Heilbronner,et al.  The eastern Tonale fault zone: a ‘natural laboratory’ for crystal plastic deformation of quartz over a temperature range from 250 to 700 °C , 2002 .

[79]  R. Carosi,et al.  Orogen-parallel tectonic transport in the Variscan belt of northeastern Sardinia (Italy): implications for the exhumation of medium-pressure metamorphic rocks , 2002, Geological Magazine.

[80]  C. Laverne,et al.  Transcurrent strain partitioning along a suture zone in the Maures massif (France): Result of eastern indenter tectonics in European Variscides? , 2002 .

[81]  A. Pelletier,et al.  Tectonique transpressive en terre Adélie au Paléoprotérozoïque (Est Antarctique) , 2002 .

[82]  R. Trindade,et al.  Thermally enhanced mimetic fabric of magnetite in a biotite granite , 2001 .

[83]  P. Matte The Variscan collage and orogeny (480–290 Ma) and the tectonic definition of the Armorica microplate: a review , 2001 .

[84]  S. Kruse,et al.  Magmatic fabrics in batholiths as markers of regional strains and plate kinematics: example of the Cretaceous Mt. Stuart batholith , 2001 .

[85]  P. A. Ziegler,et al.  Late paleozoic-early mesozoic plate boundary reorganization: collapse of the variscan orogen and opening of neotethys , 2001 .

[86]  L. Carmignani,et al.  Note Illustrative della Carta Geologica d'Italia alla scala 1:50.000 "Foglio 249 - Massa Carrara" , 2011 .

[87]  G. Ruffet,et al.  Diachronous cooling on both sides of a major strike slip fault in the Variscan Maures Massif (south-east France), as deduced from a detailed 40Ar/39Ar study , 2000 .

[88]  J. Bouchez Anisotropie de susceptibilité magnétique et fabrique des granites , 2000 .

[89]  J. Onézime,et al.  Étude pétro-structurale du complexe granitique Rouet — Plan-de-la-Tour (massifs des Maures et du Tanneron occidental, Var) , 1999 .

[90]  P. Olivier,et al.  Sigmoidal structures featuring dextral shear during emplacement of the Hercynian granite complex of Cauterets–Panticosa (Pyrenees) , 1998 .

[91]  W. Bleeker,et al.  EMPLACEMENT AND DEFORMATION OF GRANITES DURING TRANSPRESSION : MAGNETIC FABRICS OF THE ARCHEAN SPARROW PLUTON, SLAVE PROVINCE, CANADA , 1998 .

[92]  M. Brown,et al.  Granite ascent and emplacement during contractional deformation in convergent orogens , 1998 .

[93]  Mathieu Moussavou Contribution à l'histoire thermo-tectonique varisque du massif des Maures, par la typologie du zircon et la géochronologie U/Pb sur minéraux accessoires (Var, France) , 1998 .

[94]  F. Hrouda,et al.  Refined technique for susceptibility resolution into ferromagnetic and paramagnetic components based on susceptibility temperature-variation measurement , 1997 .

[95]  E. Ferré,et al.  Drainage and Emplacement of Magmas along an Inclined Transcurrent Shear Zone: Petrophysical Evidence from a Granite-Charnockite Pluton (Rahama, Nigeria) , 1997 .

[96]  Patrick Launeau,et al.  Fabric analysis using the intercept method , 1996 .

[97]  W. Griffin,et al.  THREE NATURAL ZIRCON STANDARDS FOR U‐TH‐PB, LU‐HF, TRACE ELEMENT AND REE ANALYSES , 1995 .

[98]  E. Gueguen Segmentation des marges et processus d'amincissement crustal : l'exemple du bassin liguro-provencal , 1995 .

[99]  F. Hrouda A technique for the measurement of thermal changes of magnetic susceptibility of weakly magnetic rocks by the CS-2 apparatus and KLY-2 Kappabridge , 1994 .

[100]  A. Vauchez,et al.  The Pombal granite pluton: Magnetic fabric, emplacement and relationships with the Brasiliano strike-slip setting of NE Brazil (Paraiba State) , 1994 .

[101]  B. Pluijm,et al.  Separation of paramagnetic and ferrimagnetic susceptibilities using low temperature magnetic susceptibilities and comparison with high field methods , 1994 .

[102]  P. Rochette,et al.  Rock magnetism and the interpretation of anisotropy of magnetic susceptibility , 1992 .

[103]  M. Brown,et al.  Granite magma generation, ascent and emplacement within a transpressional orogen , 1992, Journal of the Geological Society.

[104]  N. Toutin-morin,et al.  Structuration des bassins de provence orientale a la fin de l'ere primaire. , 1992 .

[105]  R. Petrini,et al.  A Hercynian suture zone in Sardinia: geological and geochemical evidence , 1992 .

[106]  G. Féraud,et al.  Datation 40Ar-39Ar du magmatisme et de filons minéralisés permiens en Provence orientale (France) , 1992 .

[107]  A. Cocherie,et al.  Genesis of a Variscan batholith: Field, petrological and mineralogical evidence from the Corsica-Sardinia batholith , 1991 .

[108]  J. Pupin,et al.  La Provence varisque : structure et évolution géologique anté-triasique / Variscan Provence : structure and Ante-Triassic geologic evolution , 1991 .

[109]  S. Haggerty Oxide textures; a mini-atlas , 1991 .

[110]  Donald H. Lindsley,et al.  Oxide minerals : petrologic and magnetic significance , 1991 .

[111]  P. Rochette,et al.  Microstructure and magnetic susceptibility applied to emplacement kinematics of granites: the example of the foix pluton (French pyrenees) , 1990 .

[112]  M. Amice Le complexe granitique de Cabeza de Araya (Estrémadure, Espagne) : zonation, structures magmatiques et magnétiques, géométrie, discussion du mode de mise en place , 1990 .

[113]  W. Franke Tectonostratigraphic units in the Variscan belt of central Europe , 1989 .

[114]  D. Potter,et al.  Single‐domain particles in rocks and magnetic fabric analysis , 1988 .

[115]  M. Amenzou Les granitoïdes hercyniens du massif des Maures (Var, France) : étude géologique et minéralogique, implications génétiques , 1988 .

[116]  D. Hutton Granite emplacement mechanisms and tectonic controls: inferences from deformation studies , 1988, Earth and Environmental Science Transactions of the Royal Society of Edinburgh.

[117]  D. Wayne,et al.  Physical and chemical response of zircons to deformation , 1988 .

[118]  P. Rochette Magnetic susceptibility of the rock matrix related to magnetic fabric studies , 1987 .

[119]  J. Pupin,et al.  Le granite de Camarat (Maures, Var, France): un immeuble polygénique, zone clé entre la Provence et la Corse , 1986 .

[120]  M. Bufalo,et al.  La limite Maures occidentales-Maures orientales (Var, France): un décrochement ductile senestre majeur entre deux provinces structurales très contrastées , 1985 .

[121]  V. Jelínek Characterization of the magnetic fabric of rocks , 1981 .

[122]  R. Steiger,et al.  Subcommission on geochronology: Convention on the use of decay constants in geo- and cosmochronology , 1977 .

[123]  P. Matte,et al.  Late Paleozoic strike-slip faulting in southern Europe and northern Africa: Result of a right-lateral shear zone between the Appalachians and the Urals , 1977 .

[124]  P. Vellutini,et al.  Le microcontinent corso-sarde, sa position initiale: Donnees paleomagnetiques et raccords geologiques , 1976 .

[125]  J. Kramers,et al.  Approximation of terrestrial lead isotope evolution by a two-stage model , 1975 .

[126]  G. Wasserburg,et al.  40Ar-39Ar ages and cosmic ray exposure ages of Apollo 14 samples† , 1971 .

[127]  G. R. Hext,et al.  The estimation of second-order tensors, with related tests and designs , 1963 .