The advent of a large amount of more precise U-Pb age data on Variscan granitoids from NW Iberia in recent years has provided a more focused picture of the magmatic history of the Western European Variscan belt (WEVB). Based on these data, three main pulses of magmatic activity seem to be well established

Fernández Suárez, Javier

García Acera, G.

Gutiérrez-Alonso, Gabriel

Gärtner, Andreas

Hofmann, Mandy

López Carmona, Alicia

Martín Garro, J.

IOP Conference Series : Earth and Environmental Science

Fernández-Suárez, Javier

Gärtner, A.

Hofmann, M.

López-Carmona, Alicia

Tomsk State University Repository

IOP Conference Series: Earth and Environmental SciencePAPER • OPEN ACCESSEpisodic melting and magmatic recycling along 50Ma in the Variscan belt linked to the orogenicevolution in NW IberiaTo cite this article: G Gutiérrez-Alonso et al 2017 IOP Conf. Ser.: Earth Environ. Sci. 110 012008 View the article online for updates and enhancements.Related contentThermodynamic modelling of metamorphicprocesses: state of the art inpseudosection approachA. López-Carmona, G. Gutiérrez-Alonso,P. A. Tishin et al.-Elastic and electrical properties ofserpentinite dehydration at hightemperatureand high pressureHong-Sen Xie, Wen-Ge Zhou, Mao-XuZhu et al.-Crustal structure across the Dabie--Suluorogenic belt revealed by seismic velocityprofilesZhiming Bai, Zhongjie Zhang andYanghua Wang-This content was downloaded from IP address 176.65.41.177 on 16/01/2018 at 05:33Episodic melting and magmatic recycling along 50 Ma in the Variscan belt linked to the orogenic evolution in NW Iberia  G Gutiérrez-Alonso1,2, A López-Carmona1,2, G García Acera1, J Martín Garro1, J Fernández-Suárez3, A Gärtner4, M Hofmann4 1Department of Geology, University of Salamanca, Plaza de los Caídos s/n, 37008, Salamanca, Spain  2Faculty of Geology and Geography, Tomsk State University, 36 Lenina Ave, Tomsk 634050, Russia 3Department of Petrology and Geochemistry, Complutense University of Madrid and IGEO-CSIC, 28040 Madrid, Spain 4Senckenberg Naturhistorische Sammlungen Dresden, Museum für Mineralogie und Geologie, Koenigsbruecker Landstr. 159, 01109 Dresden, Germany  E-mail: gabi@usal.es  Abstract. The advent of a large amount of more precise U-Pb age data on Variscan granitoids from NW Iberia in recent years has provided a more focused picture of the magmatic history of the Western European Variscan belt (WEVB). Based on these data, three main pulses of magmatic activity seem to be well established.  Variscan granitoid magmatism in NW Iberia is an example of the intimate linkage between granitoid magma production and plate convergence/collisional/post-collisional geodynamic scenarios. In the Western European Variscan belt (WEVB) realm, the major stages of convergent tectonics and its aftermath, are recorded by granitoid suites generated in a time span of about 50 million years (ca. 340-290 Ma). There is however some ongoing controversy regarding: i) whether there was a significant magmatic event in the early Carboniferous, for which there is hitherto scarce evidence, and ii) whether the Variscan magmatic activity was continuous or it rather occurred through discrete and relatively short-lived pulses.Unravelling these issues is one of the key elements to better constrain and interpret the different processes involved in the collisional scenarios that lead to the Variscan orogeny in Iberia during Late Paleozoic times [1-5] and the subsequent development of the Ibero-Armorican Arc (IAA) [6]. The advent of a large amount of more precise U-Pb age data on Variscangranitoids (and some volcanic rocks) from NW Iberia in recent years has provided a more focused picture of the magmatic history of the WEVB, providing solid ground for interpretations that link periods of more intense magmatic activity with large-scale crust-mantle processes involved in the collisional orogeny and the subsequent development of the IberoArmorican Arc. Based on the observation of those more precise U-Pb ages and new data, three main pulses of magmatic activity seem to be well established. These pulses recycle (re-melt) the previously formed granitoid rocks (Figure 1 and 2): 1) Post-orogenicgranitoid suite (POS henceforth) (ca. 305-290 Ma), that intrudes all the structural domains of the orogen, including the foreland fold and thrust belt, which makes the WEVB rather unique. The POS includes a large number of volumetrically minor intrusions of mafic and ultramafic rocks. This magmatic event has been extensively studied and dated. The POS has been interpreted as generated by lithospheric delamination triggered by the oroclinal bending of the mountain belt. Petrology                                                                                                                                              IOP PublishingIOP Conf. Series: Earth and Environmental Science 110 (2017) 012008       doi:10.1088/1755-1315/110/1/012008Content from this work may be used under the terms of the Creative Commons Attribution 3.0 licence. Any further distributionof this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI.Published under licence by IOP Publishing Ltd 12) Syn-extensional collapse granitoids (ca. 325-315 Ma): mostly crustal (S-type) peraluminousleucogranites generated by decompression melting following the extensional collapse of the mountain belt. 3) A third suite of Variscangranitoids, not considered in most of the published models, has been found with ages clustering around 340 Ma. In addition, a significant amount of ca. 340 Ma zircon xenocrysts has been found in the ca. 320 Ma syntectonicleucogranitoids of the Tormes Dome and surrounding areas, in the ca. 305 Ma Toledo Anatectic Complex and the western part of the Gredos Massif, and also as detrital zircons in Variscansyn-orogenic sediments.   Figure 1.A) Graph [Th/U] vs. Age (Ma).and B) Histogram and Kernel distribution (KDE) of single zircon U-Pb ages of Variscangranitoids in NW Iberia [7]. Data from[8-17]. Petrology                                                                                                                                              IOP PublishingIOP Conf. Series: Earth and Environmental Science 110 (2017) 012008       doi:10.1088/1755-1315/110/1/0120082  Figure 2. Proposed conceptual model for the recycling and re-melting of the three magmatic events found in NW Iberia according to the ages of the zircon grains found in them. A: Felsic magmatism of uncertain origin at ca. 340 Ma. B: Felsic magmatism at ca. 320 Ma associated with the orogenic collapse, extensional shear zones and extensive migmatization recycling previous 340 Ma granite bodies. C: Felsic and mafic magmatism of ca. 310-295 Ma that produced new zircons and recycled zircons from the two previous magmatic Variscan events. The latter event is interpreted to have occurred due to orocline triggered lithospheric delamination.  This work has been funded by the Spanish Ministry of Economy and Competitiveness under the project ODRE III-Oroclines& Delamination: Relations & Effects (CGL2013-46061-P) and the Russian Ministry of Education and Science under the project «Origin, metallogeny, climitic effects and cyclicity of Large Igneous Provinces» (14.Y26.31.0012).  References [1] Matte P 2001TheVariscan collage and orogeny (480-290 Ma) and the tectonic definition of the  Armorica microplate: a review Terra Nova 13 p 122–128 [2] Ballèvre M Bosse VDucassou CPitra P 2009Palaeozoic history of the Armorican Massif:  models for the tectonic evolution of the suture zones Comptes Rendus Geoscience. 341 p. 174–20 Petrology                                                                                                                                              IOP PublishingIOP Conf. Series: Earth and Environmental Science 110 (2017) 012008       doi:10.1088/1755-1315/110/1/0120083[3] Martínez Catalán J R Arenas R Abati J Martínez S S García F. D Suárez J FClavijo E G 2009  A rootless suture and the loss of the roots of a mountain chain: the Variscan belt of NW  Iberia Comptes Rendus Geoscience 341(2)p114-126 [4] Arenas R Sánchez Martínez S Díez Fernández R Gerdes A Abati J Fernández-Suárez J Andonaegui P González Cuadra P López-Carmona A Albert R Fuenlabrada J.M Rubio  Pascual F J 2016Allochthonous terranes involved in the Variscan suture of NW Iberia: A  review of their origin and tectonothermal evolution Earth-Science Reviews 161 p 140– 178 [5] DíezFernández R Arenas R Pereira M F Sánchez-Martínez S Albert R Martín Parra L M Rubio  Pascual F.J and Matas J 2016Tectonic evolution of Variscan Iberia: Gondwana-Laurussia collision revisited Earth-Science Reviews 162 p 269–292 [6] Weil A.B Gutiérrez-Alonso G Johnston S.T Pastor-Galán D 2013Kinematic constraints on  buckling a lithospheric-scale orocline along the northern margin of Gondwana: A geologic  synthesis Tectonophysics 582 p 25–49 [7] García Acera G 2017 Geología y geocronología U-Pb (LA-ICP-MS) de las facies graníticas del  Valle del Jerte (Cáceres) BSc Thesis University of Salamanca 32 pp [8] Gutiérrez-Alonso G Fernández-Suárez J Jeffries T E Johnston S T Pastor-Galán D Murphy J B  Franco M P Gonzalo J C 2011Diachronous post-orogenicmagmatism within a developing  orocline in Iberia, European Variscides Tectonics 30 [9] Zeck H P Wingate M TPooley G 2006Ion microprobe U-Pbzircón geochronology of a late  tectonic granitic-gabbroic rock complex within the Hercynian Iberian belt Geological  Magazine 144 p 157-177 [10] Díaz-Alvarado J Castro A Fernández C Moreno I 2011Assessing Bulk Assimilation in  Cordierite-bearing Granitoids from the Central System Batholith, Spain; Experimental,  Geochemical and Geochronological Constraints Journal of Petrology 52p 223-256 [11] Díaz-Alvarado J Fernández C Castro AMoreno I 2013SHRIMP U-Pb zircon geochronology  and termal modeling of multilayer granitoid intrusions. Implications for the building and  termal evolution of the Central System batholith, Iberian Massif, Spain Lithos 175-176 (2013) 104-123 [12] Martín Garro J 2015 Geocronología de U/Pb mediante LA-ICP-MS en circones del Complejo  anatéctico de Toledo y el batolito de los Montes de ToledoMSc Thesis Salamanca  University 50 pp [13] Pereira M F Díez-Fernández R Gama C Hofmann M Gärtner A Linnemann U 2017S-type  granite generation and emplacement during a regional switch from extensional to  contractional deformation (Central Iberian Zone, Iberian autochthonous domain, Variscan Orogeny) International Journal of Earth Scieces [14] Díez-Fernández R Pereira M F 2017Extensional orogenic collapse captured by strike-slip  tecotonics: Constrains frm structural geology and U-Pbgechronology the Pinhel shear zone  (Variscanorogen, Iberian Massif) Tectonophysics 691p 290-310 [15] Villaseca C Orejana D Belousova E AmstrongR A Perez-Soba C E Jeffries T 2011U-Pb isotopic ages and Hf isotope composition of zircons in Variscangabbros from central Spain:  evidence of variable cristal contamination Mineralogy and Petrolology 101 p 151-167 [16] Bea F Montero P Molina J F 1999Mafic precursors, peraluminousgranitoids, and late  lamprophyres in the Avila batholith: a model for the generation of Variscan batholiths in Iberia The Journal of Geology 107(4) p399-419 [17] Montero P Bea F Zinger T 2004 Edad 207Pb/206Pb en cristal único de circón de las rocas máficas  y ultramáficas del sector de Gredos, Batolito de Ávila (Sistema Central Español) Revista de la Sociedad Geológica de España 17(3-4) p157-167 Petrology                                                                                                                                              IOP PublishingIOP Conf. Series: Earth and Environmental Science 110 (2017) 012008       doi:10.1088/1755-1315/110/1/0120084

English

Episodic melting and magmatic recycling along 50 Ma in the Variscan belt linked to the orogenic evolution in NW Iberia

The advent of a large amount of more precise U-Pb age data on Variscan granitoids from NW Iberia in recent years has provided a more focused picture of the magmatic history of the Western European Variscan belt (WEVB). Based on these data, three main pulses of magmatic activity seem to be well established.Ministerio de Economía y Competitividad (MINECO)Russian Ministry of Education and ScienceDepto. de Mineralogía y PetrologíaFac. de Ciencias GeológicasTRUEpu

Docta Complutense

G Gutiérrez-Alonso

A López-Carmona

G García Acera

J Martín Garro

J Fernández-Suárez

A Gärtner

M Hofmann

Crossref

IOP Conference Series Earth and Environmental Science

Gutiérrez Alonso, Gabriel

García Acera, G

Gärtner, A

Hofmann, M

Gestion del Repositorio Documental de la Universidad de Salamanca

IOP Conference Series: Earth and Environmental SciencePAPER • OPEN ACCESSEpisodic melting and magmatic recycling along 50Ma in the Variscan belt linked to the orogenicevolution in NW IberiaTo cite this article: G Gutiérrez-Alonso et al 2017 IOP Conf. Ser.: Earth Environ. Sci. 110 012008 View the article online for updates and enhancements.Related contentThermodynamic modelling of metamorphicprocesses: state of the art inpseudosection approachA. López-Carmona, G. Gutiérrez-Alonso,P. A. Tishin et al.-Elastic and electrical properties ofserpentinite dehydration at hightemperatureand high pressureHong-Sen Xie, Wen-Ge Zhou, Mao-XuZhu et al.-Crustal structure across the Dabie--Suluorogenic belt revealed by seismic velocityprofilesZhiming Bai, Zhongjie Zhang andYanghua Wang-This content was downloaded from IP address 212.128.175.122 on 19/03/2018 at 12:21Episodic melting and magmatic recycling along 50 Ma in the Variscan belt linked to the orogenic evolution in NW Iberia  G Gutiérrez-Alonso1,2, A López-Carmona1,2, G García Acera1, J Martín Garro1, J Fernández-Suárez3, A Gärtner4, M Hofmann4 1Department of Geology, University of Salamanca, Plaza de los Caídos s/n, 37008, Salamanca, Spain  2Faculty of Geology and Geography, Tomsk State University, 36 Lenina Ave, Tomsk 634050, Russia 3Department of Petrology and Geochemistry, Complutense University of Madrid and IGEO-CSIC, 28040 Madrid, Spain 4Senckenberg Naturhistorische Sammlungen Dresden, Museum für Mineralogie und Geologie, Koenigsbruecker Landstr. 159, 01109 Dresden, Germany  E-mail: gabi@usal.es  Abstract. The advent of a large amount of more precise U-Pb age data on Variscan granitoids from NW Iberia in recent years has provided a more focused picture of the magmatic history of the Western European Variscan belt (WEVB). Based on these data, three main pulses of magmatic activity seem to be well established.  Variscan granitoid magmatism in NW Iberia is an example of the intimate linkage between granitoid magma production and plate convergence/collisional/post-collisional geodynamic scenarios. In the Western European Variscan belt (WEVB) realm, the major stages of convergent tectonics and its aftermath, are recorded by granitoid suites generated in a time span of about 50 million years (ca. 340-290 Ma). There is however some ongoing controversy regarding: i) whether there was a significant magmatic event in the early Carboniferous, for which there is hitherto scarce evidence, and ii) whether the Variscan magmatic activity was continuous or it rather occurred through discrete and relatively short-lived pulses.Unravelling these issues is one of the key elements to better constrain and interpret the different processes involved in the collisional scenarios that lead to the Variscan orogeny in Iberia during Late Paleozoic times [1-5] and the subsequent development of the Ibero-Armorican Arc (IAA) [6]. The advent of a large amount of more precise U-Pb age data on Variscangranitoids (and some volcanic rocks) from NW Iberia in recent years has provided a more focused picture of the magmatic history of the WEVB, providing solid ground for interpretations that link periods of more intense magmatic activity with large-scale crust-mantle processes involved in the collisional orogeny and the subsequent development of the IberoArmorican Arc. Based on the observation of those more precise U-Pb ages and new data, three main pulses of magmatic activity seem to be well established. These pulses recycle (re-melt) the previously formed granitoid rocks (Figure 1 and 2): 1) Post-orogenicgranitoid suite (POS henceforth) (ca. 305-290 Ma), that intrudes all the structural domains of the orogen, including the foreland fold and thrust belt, which makes the WEVB rather unique. The POS includes a large number of volumetrically minor intrusions of mafic and ultramafic rocks. This magmatic event has been extensively studied and dated. The POS has been interpreted as generated by lithospheric delamination triggered by the oroclinal bending of the mountain belt. Petrology                                                                                                                                              IOP PublishingIOP Conf. Series: Earth and Environmental Science 110 (2017) 012008       doi:10.1088/1755-1315/110/1/012008Content from this work may be used under the terms of the Creative Commons Attribution 3.0 licence. Any further distributionof this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI.Published under licence by IOP Publishing Ltd 12) Syn-extensional collapse granitoids (ca. 325-315 Ma): mostly crustal (S-type) peraluminousleucogranites generated by decompression melting following the extensional collapse of the mountain belt. 3) A third suite of Variscangranitoids, not considered in most of the published models, has been found with ages clustering around 340 Ma. In addition, a significant amount of ca. 340 Ma zircon xenocrysts has been found in the ca. 320 Ma syntectonicleucogranitoids of the Tormes Dome and surrounding areas, in the ca. 305 Ma Toledo Anatectic Complex and the western part of the Gredos Massif, and also as detrital zircons in Variscansyn-orogenic sediments.   Figure 1.A) Graph [Th/U] vs. Age (Ma).and B) Histogram and Kernel distribution (KDE) of single zircon U-Pb ages of Variscangranitoids in NW Iberia [7]. Data from[8-17]. Petrology                                                                                                                                              IOP PublishingIOP Conf. Series: Earth and Environmental Science 110 (2017) 012008       doi:10.1088/1755-1315/110/1/0120082  Figure 2. Proposed conceptual model for the recycling and re-melting of the three magmatic events found in NW Iberia according to the ages of the zircon grains found in them. A: Felsic magmatism of uncertain origin at ca. 340 Ma. B: Felsic magmatism at ca. 320 Ma associated with the orogenic collapse, extensional shear zones and extensive migmatization recycling previous 340 Ma granite bodies. C: Felsic and mafic magmatism of ca. 310-295 Ma that produced new zircons and recycled zircons from the two previous magmatic Variscan events. The latter event is interpreted to have occurred due to orocline triggered lithospheric delamination.  This work has been funded by the Spanish Ministry of Economy and Competitiveness under the project ODRE III-Oroclines& Delamination: Relations & Effects (CGL2013-46061-P) and the Russian Ministry of Education and Science under the project «Origin, metallogeny, climitic effects and cyclicity of Large Igneous Provinces» (14.Y26.31.0012).  References [1] Matte P 2001TheVariscan collage and orogeny (480-290 Ma) and the tectonic definition of the  Armorica microplate: a review Terra Nova 13 p 122–128 [2] Ballèvre M Bosse VDucassou CPitra P 2009Palaeozoic history of the Armorican Massif:  models for the tectonic evolution of the suture zones Comptes Rendus Geoscience. 341 p. 174–20 Petrology                                                                                                                                              IOP PublishingIOP Conf. Series: Earth and Environmental Science 110 (2017) 012008       doi:10.1088/1755-1315/110/1/0120083[3] Martínez Catalán J R Arenas R Abati J Martínez S S García F. D Suárez J FClavijo E G 2009  A rootless suture and the loss of the roots of a mountain chain: the Variscan belt of NW  Iberia Comptes Rendus Geoscience 341(2)p114-126 [4] Arenas R Sánchez Martínez S Díez Fernández R Gerdes A Abati J Fernández-Suárez J Andonaegui P González Cuadra P López-Carmona A Albert R Fuenlabrada J.M Rubio  Pascual F J 2016Allochthonous terranes involved in the Variscan suture of NW Iberia: A  review of their origin and tectonothermal evolution Earth-Science Reviews 161 p 140– 178 [5] DíezFernández R Arenas R Pereira M F Sánchez-Martínez S Albert R Martín Parra L M Rubio  Pascual F.J and Matas J 2016Tectonic evolution of Variscan Iberia: Gondwana-Laurussia collision revisited Earth-Science Reviews 162 p 269–292 [6] Weil A.B Gutiérrez-Alonso G Johnston S.T Pastor-Galán D 2013Kinematic constraints on  buckling a lithospheric-scale orocline along the northern margin of Gondwana: A geologic  synthesis Tectonophysics 582 p 25–49 [7] García Acera G 2017 Geología y geocronología U-Pb (LA-ICP-MS) de las facies graníticas del  Valle del Jerte (Cáceres) BSc Thesis University of Salamanca 32 pp [8] Gutiérrez-Alonso G Fernández-Suárez J Jeffries T E Johnston S T Pastor-Galán D Murphy J B  Franco M P Gonzalo J C 2011Diachronous post-orogenicmagmatism within a developing  orocline in Iberia, European Variscides Tectonics 30 [9] Zeck H P Wingate M TPooley G 2006Ion microprobe U-Pbzircón geochronology of a late  tectonic granitic-gabbroic rock complex within the Hercynian Iberian belt Geological  Magazine 144 p 157-177 [10] Díaz-Alvarado J Castro A Fernández C Moreno I 2011Assessing Bulk Assimilation in  Cordierite-bearing Granitoids from the Central System Batholith, Spain; Experimental,  Geochemical and Geochronological Constraints Journal of Petrology 52p 223-256 [11] Díaz-Alvarado J Fernández C Castro AMoreno I 2013SHRIMP U-Pb zircon geochronology  and termal modeling of multilayer granitoid intrusions. Implications for the building and  termal evolution of the Central System batholith, Iberian Massif, Spain Lithos 175-176 (2013) 104-123 [12] Martín Garro J 2015 Geocronología de U/Pb mediante LA-ICP-MS en circones del Complejo  anatéctico de Toledo y el batolito de los Montes de ToledoMSc Thesis Salamanca  University 50 pp [13] Pereira M F Díez-Fernández R Gama C Hofmann M Gärtner A Linnemann U 2017S-type  granite generation and emplacement during a regional switch from extensional to  contractional deformation (Central Iberian Zone, Iberian autochthonous domain, Variscan Orogeny) International Journal of Earth Scieces [14] Díez-Fernández R Pereira M F 2017Extensional orogenic collapse captured by strike-slip  tecotonics: Constrains frm structural geology and U-Pbgechronology the Pinhel shear zone  (Variscanorogen, Iberian Massif) Tectonophysics 691p 290-310 [15] Villaseca C Orejana D Belousova E AmstrongR A Perez-Soba C E Jeffries T 2011U-Pb isotopic ages and Hf isotope composition of zircons in Variscangabbros from central Spain:  evidence of variable cristal contamination Mineralogy and Petrolology 101 p 151-167 [16] Bea F Montero P Molina J F 1999Mafic precursors, peraluminousgranitoids, and late  lamprophyres in the Avila batholith: a model for the generation of Variscan batholiths in Iberia The Journal of Geology 107(4) p399-419 [17] Montero P Bea F Zinger T 2004 Edad 207Pb/206Pb en cristal único de circón de las rocas máficas  y ultramáficas del sector de Gredos, Batolito de Ávila (Sistema Central Español) Revista de la Sociedad Geológica de España 17(3-4) p157-167 Petrology                                                                                                                                              IOP PublishingIOP Conf. Series: Earth and Environmental Science 110 (2017) 012008       doi:10.1088/1755-1315/110/1/0120084

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Episodic melting and magmatic recycling along 50 Ma in the Variscan belt linked to the orogenic evolution in NW Iberia

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