Relationships between syn-orogenic sedimentation and nappe emplacement in the hinterland of the Variscan belt in NW Iberia deduced from detrital zircons

Catalán, José R. Martı́nez; Clavijo, Emílio González; Meireles, Carlos; Fernández, Rubén Díez; Bevis, James

doi:10.1017/s001675681500028x

Cited by 30 publications

(22 citation statements)

References 81 publications

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“…The Parautochthon consists of Cambrian, Ordovician, and Silurian metasediments and volcanics exhibiting stratigraphic and igneous affinities with the Autochthon and representing a distal part of the Gondwanan continental margin (Dias da Silva, Valverde‐Vaquero, et al, ; Farias et al, ). Deformation and metamorphism are Variscan, and early Carboniferous syn‐orogenic flysch‐type deposits related with the emplacement of the allochthonous complexes occur in both the Autochthon and Parauthochthon (Dias da Silva, Linnemann, et al, ; Martínez Catalán et al, , ).…”

Section: Geological Settingmentioning

confidence: 99%

Magnetic Anomalies in Extensional Detachments: The Xistral Tectonic Window of the Lugo Dome (NW Spain)

et al. 2018

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The Eastern Galicia Magnetic Anomaly (EGMA) is a conspicuous feature of the aeromagnetic map of Iberia, which structurally overlaps the Lugo and Sanabria domes, two spatially linked late Variscan extensional structures that delineate a segment of the Ibero‐Armorican Arc. In the northern part of the Lugo Dome, the Xistral Tectonic Window exposes a deep section of the continental crust, which includes several extensional detachments and associated shear zones. The aim is to check whether or not there is a correlation between the extensional process and the EGMA. A map of the magnetic anomaly of the Xistral Tectonic Window acquired on land improves the resolution of the aeromagnetic data and shows that the EGMA is actually composed by several shorter wavelength anomalies reaching amplitudes up to 1,214 nT. Their location in relation to outcropping rocks and structures, together with 2‐D modeling, shows a conspicuous link between the anomalies and the extensional detachments. On a larger scale, the EGMA forms the northern part of a largeanomaly occupying the core of the Central Iberian Arc. This anomaly can be related to extension caused by gravitational collapse of the thickened Variscan crust, implying that like the EGMA, local anomalies might reflect extensional structures, many of which may remain buried. Our study may shed light on the origin of magnetic anomalies in other gneiss domes as it shows that they can be related with the doming process instead of being inherited from older rocks presently outcropping at the core of the domes.

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Section: Geological Settingmentioning

confidence: 99%

Magnetic Anomalies in Extensional Detachments: The Xistral Tectonic Window of the Lugo Dome (NW Spain)

et al. 2018

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“…370-342 Ma;Bea et al, 2009). Subsequent thrusting is responsible for the establishment of Viséan syn-orogenic basins at the advancing front of the Iberian Allochthon (Martínez Catalán et al, 2016), and considered coeval with subhorizontal ductile shearing in the Iberian Parautochthon, dated at ca. 340 Ma (Dallmeyer et al, 1997).…”

Section: Iberian Parautochthon and Autochthon Of Nw And Central Iberiamentioning

confidence: 99%

Tectonic evolution of Variscan Iberia: Gondwana–Laurussia collision revisited

Fernández

Arenas

Pereira

et al. 2016

Earth-Science Reviews

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103

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An integrated interpretation of the late Paleozoic structural and geochronological record of the Iberian Massif is presented and discussed under the perspective of a Gondwana-Laurussia collision giving way to the Variscan orogen. Compressional and extensional structures developed during the building of the Variscan orogenic crust of Iberia are linked together into major tectonic events operating at lithosphere scale. A review of the tectonometamorphic and magmatic evolution of the Iberian Massif reveals backs and forths in the overall convergence between Gondwana and Laurussia during the amalgamation of Pangea in late Paleozoic times. Stages dominated by lithosphere compression are characterized by subduction, both oceanic and continental, development of magmatic arcs, (over-and under-) thrusting of continental lithosphere, and folding. Variscan convergence resulted in the eventual transference of a large allochthonous set of peri-Gondwanan terranes, the Iberian Allochthon, onto the Gondwana mainland. The Iberian Allochthon bears the imprint of previous interaction between Gondwana and Laurussia, including their juxtaposition after the closure of the Rheic Ocean in Lower Devonian times. Stages governed by lithosphere extension are featured by the opening of two short-lived oceanic basins that dissected previous Variscan orogenic crust, first in the Lower-Middle Devonian, following the closure of the Rheic Ocean, and then in the early Carboniferous, following the emplacement of the peri-Gondwanan allochthon. An additional, major intra-orogenic extensional event in the early-middle Carboniferous dismembered the Iberian Allochthon into individual thrust stacks separated by extensional faults and domes. Lateral tectonics played an important role through the Variscan orogenesis, especially during the creation of new tectonic blocks separated by intracontinental strike-slip shear zones in the late stages of continental convergence. Units, (6) Upper Allochthonous Units, (7) Beja-Acebuches Ophiolite, and (8) South Portuguese Zone. Gathering of 4, 5, and 6 will be also referred to as Iberian Allochthon (or simply Allochthon). A simple restoration of the cross-section shown in Figure 3 (Fig. 4a) reveals two major suture zones featured with ophiolitic units with different protolith ages. The NNE-dipping suture represented by the Beja-Acebuches Ophiolite (Bard and Moine, 1979; Munhá et al., 1986; Quesada et al., 1994) cuts the suture marked by the Allochthonous Ophiolitic Units (Arenas et al., 1986) and divides the Iberian Massif in two major blocks. The northern block comprises the Cantabrian Zone, and the Iberian Autochthon, Parautochthon and Allochthon, all of which have Gondwanan affinity

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“…320 Ma syntectonic leucogranitoids of the Tormes dome and surrounding areas (López-Moro et al, 2018), in the ca. 305 Ma Toledo Anatectic Complex (Martín Garro, 2015), and as detrital zircons in Variscan synorogenic sediments of the Cantabrian zone (Pastor- Galán et al, 2013) and the Central Iberian and Galicia Tras-os-Montes zones (Da Martínez Catalán et al, 2016). Furthermore, volcanic rocks (ash-fall beds) in the Cantabrian zone have been recently dated as ca.…”

Section: Introductionmentioning

confidence: 99%

Exhuming a cold case: The early granodiorites of the northwest Iberian Variscan belt—A Visean magmatic flare-up?

et al. 2018

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In this study we report laser ablation-inductively coupled plasma-mass spectrometer U-Pb ages of granitoids from the so-called early granodiorites of the northwest Iberian Variscan belt. The U-Pb results attest to significant magmatic activity in Visean time (ca. 347-337 Ma) that generated a hitherto poorly constrained granitoid suite in the northwest Iberian tract of the western European Variscan belt realm. This early Carboniferous suite (ECS) is mainly composed of peraluminous cold and hot crustal granodiorites and monzogranites with minor associated mafic rocks that attest to minor involvement of mantle melting. Based on the geochronological and geochemical data, we compare the Visean granitoids with younger Variscan granitoids in northwest Iberia and, in view of the tectonothermal scenarios of the Variscan collision in northwest Iberia, propose a model for the genesis of the ECS in northwest Iberia that involves rapid melting upon fast exhumation of the thickened Gondwanan crust in the course of the protracted Variscan collision.

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Relationships between syn-orogenic sedimentation and nappe emplacement in the hinterland of the Variscan belt in NW Iberia deduced from detrital zircons

Cited by 30 publications

References 81 publications

Magnetic Anomalies in Extensional Detachments: The Xistral Tectonic Window of the Lugo Dome (NW Spain)

Magnetic Anomalies in Extensional Detachments: The Xistral Tectonic Window of the Lugo Dome (NW Spain)

Tectonic evolution of Variscan Iberia: Gondwana–Laurussia collision revisited

Exhuming a cold case: The early granodiorites of the northwest Iberian Variscan belt—A Visean magmatic flare-up?

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