The evolution of the subcontinental mantle beneath the Central Iberian Zone: Geochemical tracking of its mafic magmatism from the Neoproterozoic to the Cenozoic

Villaseca, Carlos; García, David Orejana; Higueras, Pablo; Pérez-Soba, Cecilia; Serrano, Javier García; Lorenzo, Saturnino

doi:10.1016/j.earscirev.2022.103997

Cited by 12 publications

(22 citation statements)

References 108 publications

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“…7), supporting a similar petrogenesis. These rocks are close to the Gb2 magmatism of the SCS characterised by calc-alkaline microdioritic dyke swarms accompanied by felsic granitic porphyries of 292 Ma (Orejana et al, 2020;Villaseca et al, 2022). The microdiorite dyke swarms have been interpreted as the melting products of an enriched lithospheric mantle mixed locally with felsic magmas (Orejana et al, 2020).…”

Section: Origin Of the Magmatismmentioning

confidence: 52%

“…Assuming a mixing model between mantle-derived magmas and the crust (i.e. assimilation, anataxis) for the origin of the Permian magmatism as suggested for the rest of the Iberian Chain (Lago et al, 2004) and the coeval SCS magmatism (Orejana et al, 2020;Villaseca et al, 2022), in Atienza, the mantle signature is negligible, and the source of the melts could be close to the crust (Fig. 7).…”

Section: Origin Of the Magmatismmentioning

confidence: 99%

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El magmatismo de Atienza (NW de la Cordillera Ibérica): edad, origen y arquitectura del sistema magmático

et al. 2023

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A sill covering an area of more than 15 km2, several dykes up to 5 m thick and a volcanoclastic deposit crop out with similar petrology in the sector of Atienza (NW Iberian Chain, Spain). They consist of calc-alkaline porphyritic andesites with phenocrysts of plagioclase, amphibole, biotite, garnet and orthopyroxene. Based on U–Pb zircon analysis, an age of 290 ± 3 Ma (Sakmarian-Artinskian in the Cisuralian) has been calculated for this magmatism. The chemistry and geothermobarometry on amphibole crystals revealed crystallisation at different depths between 31 and 16 km, involving several events of magma recharge and fractional crystallisation. Magma ascent led to destabilisation of the amphibole crystals, their replacement by biotite, and the formation of thick microcrystalline coronas. Whole-rock trace element and isotopic compositions support a strong crustal influence in the origin of the magma. Crustal melting was produced by heating generated after lithospheric thinning, delamination, and asthenospheric rise produced after the uplift of the Variscan Orogen and the oroclinal folding of the Iberian Massif.

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Section: Origin Of the Magmatismmentioning

confidence: 52%

Section: Origin Of the Magmatismmentioning

confidence: 99%

El magmatismo de Atienza (NW de la Cordillera Ibérica): edad, origen y arquitectura del sistema magmático

et al. 2023

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“…In the Iberian Massif most of the Variscan mafic magmatism implied melting of lithospheric mantle sources, variably enriched due to crustal material subducted during the Late Cadomian and the Variscan orogenic cycles (Bea et al., 2021; Orejana et al., 2020; Villaseca et al., 2004). Nevertheless, the moderately high initial εNd values (from +5.4 to +5.8) and younger model ages ( T DM = 735–620 Ma) of the tholeiitic rocks of Central Iberian (López‐Moro et al., 2007), coupled with their low Th/Yb and relatively high Nb/U (mostly from 20 to 47) values, suggests a scarce continental crustal imprint, and therefore, the lack of supra‐subduction signatures and the existence of an old (pre‐Neoproterozoic) heterogeneous enriched subcontinental mantle beneath Central Iberia (Villaseca et al., 2022). In the regional setting of Matachel magmatic province, provenance of the Group #1 “primitive” samples from an enriched MORB‐type source beneath the Ossa‐Morena Zone places additional constraints on magma source identification.…”

Section: Discussionmentioning

confidence: 99%

Low–Ti Continental Tholeiite Origin of Magmas With Calc‐Alkaline Signature in Transcurrent Settings: The Mississippian Matachel Volcanic Field (SW Iberian Massif)

Sarrionandia,

Errandonea‐Martin,

Larrondo

et al. 2023

Geochem Geophys Geosyst

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In the Mississippian Matachel small volcanic field of the Ossa‐Morena Zone (southern Iberian Massif) outpoured basic‐intermediate lavas exhibit geochemical characteristics of Low‐Ti continental tholeiites and calc‐alkaline lavas. Low‐Ti continental tholeiites integrate two contrasting groups of rocks: basalts (Mg#: 54 to 70; Ti/Zr: 61–79; LaN/LuN: 1.6–2.9; εNdi: +4.0–+6.6; “Group #1”), and basalts and basaltic andesites (Mg#: 43 to 66; Ti/Zr: 36–58; LaN/LuN: 2.5–5.9; εNdi: −0.2–+3.5; “Group #2”). Primitive Group #1 tholeiitic magmas were generated by partial melting of a garnet‐free lherzolite from an enriched lithospheric mantle, near the lithosphere‐asthenosphere thermal boundary layer (with a very limited asthenosphere melting input). Progressive interaction of these magmas with crustal alkali igneous rocks resulted in the formation of the petrological evolutionary trends observed, to a larger extent in the case of Group #2 Low‐Ti tholeiites. Further assimilation of amphibole‐rich calc‐alkaline metaigneous rocks might have originated the basalts and basaltic andesites with calc‐alkaline signature (Mg#: 33 to 56; Ti/Zr: 25–78; LaN/LuN: 2.0–5.6; εNdi: +2.8–+4.8). These exhibit a “Cordilleran‐type” evolutionary trend, though are unrelated to plate convergence. The magmas with calc‐alkaline signature attest to a closed‐system differentiation process controlled by the fractionation of plagioclase, clinopyroxene, magnetite and ilmenite. It is proposed that Mississippian lithospheric‐scale intra‐continental wrenching, unrelated to coeval mantle plume upwelling, reworked complexly docked mantle domains and triggered mantle melting. Enduring mid‐upper crustal processes (magma storage in mid‐crustal chambers and crustal assimilation) likely shaped the latest petrologic and geochemical aspects of the Matachel Low‐Ti tholeiites and related rocks with calc‐alkaline signature.

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“…However, negative εNd(t) values and significantly older isotopic model ages found in the youngest Carboniferous mafic rocks suggest derivation from an SCLM contaminated by Late Paleozoic subduction [8]. This evolution of the mantle source beneath Gondwana is shared by most Variscan massifs [8], revealing some temporal and spatial isotopic variations along the orogen [63,64]. [34];2 [26]; 3 [25]; 4 [33]; 5 [16]; 6 [44]; 7 [43]; 8 [23]; 9 [19]; 10 [67];11 [68]; 12 [29]; 13 [69]; 14 [70]; 15 [18]; 16 [71]; 17 [72]; 18 [73] and 19 [74]; compiled magmatic (black bars) and metamorphic (magenta bars) ages; U-Pg ages from this study (dark blue and green bars); (b) simplified geological map of the Ossa-Morena Zone showing a compilation of magmatism and metamorphism ages (adapted from [18,43]).…”

Section: Tournaisian: Earliest Stage Of Arc-magmatismmentioning

confidence: 93%

Changing Carboniferous Arc Magmatism in the Ossa-Morena Zone (Southwest Iberia): Implications for the Variscan Belt

et al. 2022

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Carboniferous magmatism in southwestern Iberia was continuously active for more than 60 m.y. during the development of the Appalachian-Variscan belt of North America, North Africa and Western-Central Europe. This collisional orogen that records the closure of the Rheic Ocean is essential to understanding the late Paleozoic amalgamation of the Pangea supercontinent. However, the oblique convergence between Laurussia and Gondwana that lasted from the Devonian to the Carboniferous was likely more complex. Recently, a new tectonic model has regarded the Iberia Variscan belt as the site of coeval collisional and accretionary orogenic processes. Early Carboniferous plutonic rocks of southwest Iberia indicate arc magmatism in Gondwana. The Ossa-Morena Zone (OMZ) acted as the upper plate in relation to the geometry of the Paleotethys subduction. This active accretionary-extensional margin was progressively involved in a collisional phase during the Late Carboniferous. Together, the Évora Massif and the Beja Igneous Complex include three successive stages of bimodal magmatism, with a chemical composition indicative of a long-lived subduction process lasting from the Tournaisian to the Moscovian in the OMZ. The earliest stage of arc magmatism includes the Tournaisian Beja and Torrão gabbro-dioritic rocks of the Layered Gabbroic Sequence. We present new geochemical and Nd isotopic and U-Pb geochronological data for magmatic rocks from the Main (Visean-Serpukhovian) and Latest (Bashkirian-Moscovian) stages of arc magmatism. Visean Toca da Moura trachyandesite and rhyolites and Bashkirian Baleizão porphyries and Alcáçovas quartz diorite share enriched, continental-crust like characteristics, as indicated by major and trace elements, mainly suggesting the addition of calc-alkaline magma extracted from various mantle sources in a subduction-related setting (i.e., Paleotethys subduction). New U-Pb zircon geochronology data have allowed us to establish a crystallization age of 317 ± 3 Ma (Bashkirian) for Alcáçovas quartz diorite that confirms a temporal link with Baleizão porphyry. Positive εNd(t) values for the Carboniferous igneous rocks of the Beja Igneous Complex and the Évora gneiss dome indicate production of new juvenile crust, whereas negative εNd(t) values also suggest different grades of magma evolution involving crustal contamination. The production and evolution of Carboniferous continental crust in the OMZ was most likely associated with the development of an active continental margin during the convergence of the Paleotethys Ocean with Gondwana, involving juvenile materials and different grades of crustal contamination.

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The evolution of the subcontinental mantle beneath the Central Iberian Zone: Geochemical tracking of its mafic magmatism from the Neoproterozoic to the Cenozoic

Cited by 12 publications

References 108 publications

El magmatismo de Atienza (NW de la Cordillera Ibérica): edad, origen y arquitectura del sistema magmático

El magmatismo de Atienza (NW de la Cordillera Ibérica): edad, origen y arquitectura del sistema magmático

Low–Ti Continental Tholeiite Origin of Magmas With Calc‐Alkaline Signature in Transcurrent Settings: The Mississippian Matachel Volcanic Field (SW Iberian Massif)

Changing Carboniferous Arc Magmatism in the Ossa-Morena Zone (Southwest Iberia): Implications for the Variscan Belt

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