The amphibolites from the Ossa–Morena/Central Iberian Variscan suture (Southwestern Iberian Massif): geochemistry and tectonic interpretation

Gómez-Pugnaire, María Teresa; Azor, António; Fernández-Soler, J.M.; Sánchez‐Vizcaíno, Vicente López

doi:10.1016/s0024-4937(03)00018-5

Cited by 66 publications

(36 citation statements)

References 41 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…1B). The contact with the Central Iberian Zone, to the north, is marked by the Badajoz-Córdoba fault, interpreted as a major Variscan intra-continental shear zone (Burg et al, 1981;Azor et al, 1994;Gómez-Pugnaire et al, 2003;Simancas et al, 2005;Pereira et al, 2007Pereira et al, , 2009Pereira et al, , 2010aPereira et al, , 2010bPereira et al, , 2012a (Fig. 1).…”

Section: Geological Settingmentioning

confidence: 99%

SHRIMP U–Pb zircon dating of the Valencia del Ventoso plutonic complex, Ossa-Morena Zone, SW Iberia: Early Carboniferous intra-orogenic extension-related ‘calc-alkaline’ magmatism

et al. 2015

View full text Add to dashboard Cite

Section: Geological Settingmentioning

confidence: 99%

SHRIMP U–Pb zircon dating of the Valencia del Ventoso plutonic complex, Ossa-Morena Zone, SW Iberia: Early Carboniferous intra-orogenic extension-related ‘calc-alkaline’ magmatism

et al. 2015

View full text Add to dashboard Cite

“…1; Eguiluz et al, 1990;Azor et al, 1994;Pereira et al, 2008aPereira et al, , 2010. This shear zone is either a Variscan suture accounting for closure of an early Paleozoic marine basin of unknown extent (Azor et al, 1994;Ordóñez Casado, 1998;Gómez-Pugnaire et al, 2003;Simancas et al, 2005), or it is a Neoproterozoic suture reworked during the Variscan cycle (Ábalos et al, 1991;Quesada, 1991;Eguíluz et al, 2000).…”

Section: Variscan Metamorphic Belts With High-pressure Rocks In Iberiamentioning

confidence: 99%

Peralkaline and alkaline magmatism of the Ossa-Morena zone (SW Iberia): Age, source, and implications for the Paleozoic evolution of Gondwanan lithosphere

2015

View full text Add to dashboard Cite

The Ossa-Morena zone in SW Iberia represents a section of the northern margin of West Gondwana that formed part of a Cordilleran-type orogenic system during the Neoproterozoic (Cadomian orogeny). The crustal section in this zone preserves the record of rifting that led to the opening of the Rheic Ocean in the early Paleozoic and the collision of Gondwana and Laurussia in the late Paleozoic (Variscan orogeny). We present U-Pb zircon data from three alkaline to peralkaline syenites that intruded Neoproterozoic and Cambrian strata and give crystallization ages ranging between ca. 490 Ma and 470 Ma. Lu/Hf isotopic data from these zircons give positive initial e Hf values (0 ≤ e Hf(t) ≤ +11.5) that approach the model values for the depleted mantle at the time of crystallization. This suggests that a significant proportion of the magma was derived from the mantle, with limited mixing/assimilation with crustal-derived melts. Alkaline/peralkaline magmatic suites of similar age and chemical composition intruded other sections of the northern margin of West Gondwana and along the boundaries of the continental blocks that today make up Iberia. These blocks are further characterized by the presence of high-pressure metamorphic belts that formed during accretion and subsequent collision of peri-Gondwanan domains against Laurussia during the Devonian and Carboniferous (Variscan orogeny). Our U-Pb and Lu-Hf data set indicates that during the Cambrian-Ordovician transition, lithosphere extension reached a stage of narrow intracontinental rifting, where deeply sourced magmas, probably coming from the lower crust and/or the upper mantle, intruded continental upper crust across various sections of previously stretched crust. We propose that necking of the Gondwana lithosphere into several continental microblocks with fertile mantle beneath them compartmentalized extension (multiblock model), which favored the onset of early Paleozoic peralkaline and alkaline magmas. The boundaries of microblocks represent zones of inherited crustal weakness that were later reactivated during the late Paleozoic as major accretionary faults related to the amalgamation of Pangea during the Variscan orogeny. Our dynamic model provides an explanation for the unusual spatial relationship between peralkaline and alkaline igneous provinces (usually shallow in the crust) and the occurrence of high-pressure rocks. Our observations suggest that Cordilleran-type orogens subjected to extension after long-lived subduction can develop wide continental platforms that feature multiple continental blocks. In addition, the formation of sequenced high-pressure belts in collisional orogens can be explained as the ultimate consequence of multiple necking events within continental lithosphere during previous collapse of a Cordilleran-type orogen.

show abstract

“…Northwards, the Ossa-Morena Zone and the Central Iberian Zone represent the hinterland, with penetrative ductile deformations and variable metamorphism. The boundary between the South Portuguese and the Ossa-Morena Zone is generally interpreted as the Rheic suture, while the Ossa-Morena/Central Iberian contact seems to correspond to a lesser-scale suture, attesting the closure of a narrow ocean (Gómez-Pugnaire et al, 2003;Simancas et al, 2013).…”

Section: Geological Settingmentioning

confidence: 99%

Mesozoic and Cenozoic exhumation history of the SW Iberian Variscides inferred from low-temperature thermochronology

et al. 2015

View full text Add to dashboard Cite

The amphibolites from the Ossa–Morena/Central Iberian Variscan suture (Southwestern Iberian Massif): geochemistry and tectonic interpretation

Cited by 66 publications

References 41 publications

SHRIMP U–Pb zircon dating of the Valencia del Ventoso plutonic complex, Ossa-Morena Zone, SW Iberia: Early Carboniferous intra-orogenic extension-related ‘calc-alkaline’ magmatism

SHRIMP U–Pb zircon dating of the Valencia del Ventoso plutonic complex, Ossa-Morena Zone, SW Iberia: Early Carboniferous intra-orogenic extension-related ‘calc-alkaline’ magmatism

Peralkaline and alkaline magmatism of the Ossa-Morena zone (SW Iberia): Age, source, and implications for the Paleozoic evolution of Gondwanan lithosphere

Mesozoic and Cenozoic exhumation history of the SW Iberian Variscides inferred from low-temperature thermochronology

Contact Info

Product

Resources

About