Imaging the crustal structure of the Central Iberian Zone (Variscan Belt): The ALCUDIA deep seismic reflection transect

Poyatos, D. Martínez; Carbonell, Ramón; Palomeras, Imma; Simancas, José Fernando; Ayarza, P.; Martí, David; Azor, António; Jabaloy, A.; Cuadra, P. González; Tejero, Rosa; Parra, Luis Miguel Martín; Matas, Jerónimo; Lodeiro, Francisco González; Pérez-Estaún, Andrés; Lobón, J. L. García; Mansilla, Luis

doi:10.1029/2011tc002995

Cited by 48 publications

(77 citation statements)

References 83 publications

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“…Previous studies using PRF in the Iberian massif and passive seismic profiles agree with our values for crustal thickness within the error bars (e.g. Julià & Mejías 2004;Banda et al 1983;Fernández et al 2004;Palomeras et al 2009;Martinez Poyatos et al 2012;Thurner et al 2014).…”

Section: Crustal Thickness Valuessupporting

confidence: 77%

“…In this study and in previous works (Banda et al 1983;Simancas et al 2003;Martinez Poyatos et al 2012), the south of the Iberian massif sampled by our study displays a rather flat Moho discontinuity without traces of the crustal root expected below a collisional orogen or major suture boundaries. The crustal thickness values are similar to other parts of the Variscan terranes in Europe (e.g.…”

Section: Flat Moho In the South Of The Iberian Massifmentioning

confidence: 81%

“…They report a crustal thickness of 30-33 km underneath the Iberian Massif with a flat Moho discontinuity (e.g. Banda et al 1983;Fernández et al 2004;Palomeras et al 2009;Martinez Poyatos et al 2012). In the Betics domain the crustal thickness values vary sharply from 38 km beneath the Granada basin down to 22 km in the east, close to the Mediterranean coast (Banda et al 1983).…”

Section: Geological Setting and Previous Analysismentioning

confidence: 99%

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Crustal thickness and images of the lithospheric discontinuities in the Gibraltar arc and surrounding areas

Mancilla

Stich

Morales

et al. 2015

Geophysical Journal International

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S U M M A R YThe Gibraltar arc and surrounding areas are a complex tectonic region and its tectonic evolution since Miocene is still under debate. Knowledge of its lithospheric structure will help to understand the mechanisms that produced extension and westward motion of the Alboran domain, simultaneously with NW-SE compression driven by Africa-Europe plates convergence. We perform a P-wave receiver function analysis in which we analyse new data recorded at 83 permanent and temporary seismic broad-band stations located in the South of the Iberian peninsula. These data are stacked and combined with data from a previous study in northern Morocco to build maps of thickness and average v P /v S ratio for the crust, and cross-sections to image the lithospheric discontinuities beneath the Gibraltar arc, the Betic and Rif Ranges and their Iberian and Moroccan forelands. Crustal thickness values show strong lateral variations in the southern Iberia peninsula, ranging from ∼19 to ∼46 km. The Variscan foreland is characterized by a relatively flat Moho at ∼31 km depth, and an average v P /v S ratio of ∼1.72, similar to other Variscan terranes, which may indicate that part of the lower crustal orogenic root was lost. The thickest crust is found at the contact between the Alboran domain and the External Zones of the Betic Range, while crustal thinning is observed southeastern Iberia (down to 19 km) and in the Guadalquivir basin where the thinning at the Iberian paleomargin could be still preserved. In the cross-sections, we see a strong change between the eastern Betics, where the Iberian crust underthrusts and couples to the Alboran crust, and the western Betics, where the underthrusting Iberian crust becomes partially delaminated and enters into the mantle. The structures largely mirror those on the Moroccan side where a similar detachment was observed in northern Morocco. We attribute a relatively shallow strong negativepolarity discontinuity to the lithosphere-asthenosphere boundary. This means relatively thin lithosphere ranging from ∼50 km thickness in southeastern Iberia and northeastern Morocco to ∼90-100 km beneath the western Betics and the Rif, with abrupt changes of ∼30 km under the central Betics and northern Morocco. Our observations support a geodynamic scenario where in western Betics oceanic subduction has developed into ongoing continental subduction/delamination while in eastern Betics this process is inactive.

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Section: Crustal Thickness Valuessupporting

confidence: 77%

Section: Flat Moho In the South Of The Iberian Massifmentioning

confidence: 81%

Section: Geological Setting and Previous Analysismentioning

confidence: 99%

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Crustal thickness and images of the lithospheric discontinuities in the Gibraltar arc and surrounding areas

Mancilla

Stich

Morales

et al. 2015

Geophysical Journal International

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“…Thicknesses >15 km for the lower crust are often reported in the literature (Rudnick and Fountain, 1995;Martínez-Poyatos et al, 2012;Thybo and Artemieva, 2013).…”

Section: Accepted Manuscriptmentioning

confidence: 99%

Crustal structure and evolution of the Pyrenean-Cantabrian belt: A review and new interpretations from recent concepts and data

et al. 2018

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International audienceThis paper provides a synthesis of current data and interpretations on the crustal structure of the Pyrenean-Cantabrian orogenic belt, and presents new tectonic models for representative transects. The Pyrenean orogeny lasted from Santonian (~84 Ma) to early Miocene times (~20 Ma), and consisted of a spatial and temporal succession of oceanic crust/exhumed mantle subduction, rift inversion and continental collision processes at the Iberia-Eurasia plate boundary. A good coverage by active-source (vertical-incidence and wide-angle reflection) and passive-source (receiver functions) seismic studies, coupled with surface data have led to a reasonable knowledge of the present-day crustal architecture of the Pyrenean-Cantabrian belt, although questions remain. Seismic imaging reveals a persistent structure, from the central Pyrenees to the central Cantabrian Mountains, consisting of a wedge of Eurasian lithosphere indented into the thicker Iberian plate, whose lower crust is detached and plunges northwards into the mantle. For the Pyrenees, a new scheme of relationships between the southern upper crustal thrust sheets and the Axial Zone is here proposed. For the Cantabrian belt, the depth reached by the N-dipping Iberian crust and the structure of the margin are also revised.The common occurrence of lherzolite bodies in the northern Pyrenees and the seismic velocity and potential field record of the Bay of Biscay indicate that the precursor of the Pyrenees was a hyperextended and strongly segmented rift system, where narrow domains of exhumed mantle separated the thinned Iberian and Eurasian continental margins since the Albian-Cenomanian. The exhumed mantle in the Pyrenean rift was largely covered by a Mesozoic sedimentary lid that had locally glided along detachments in Triassic evaporites. Continental margin collision in the Pyrenees was preceded by subduction of the exhumed mantle, accompanied by the pop-up thrust expulsion of the off-scraped sedimentary lid above. To the west, oceanic subduction of the Bay of Biscay under the North Iberian margin is supported by an upper plate thrust wedge, gravity and magnetic anomalies, and 3D inclined sub-crustal reflections. However, discrepancies remain for the location of continent-ocean transitions in the Bay of Biscay and for the extent of oceanic subduction. The plate-kinematic evolution during the Mesozoic, which involves issues as the timing and total amount of opening, as well as the role of strike-slip drift, is also under debate, discrepancies arising from first-order interpretations of the adjacent oceanic magnetic anomaly record

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“…In order to understand better the aforementioned geodynamic scenarios for the origin of the CVP (i.e., "aborted" rift vs. lithospheric folding), we address here the study of the geometry of the Moho and lithosphere-asthenosphere interfaces in the CVP and its vicinity by means of gravity analysis and 2+1/2D modeling. Gravity models have been constrained by deep seismic soundings (Martínez Poyatos et al, 2012;Simancas et al, 2013, Ehsan et al, 2014, 2015 and 3D seismic tomography (Palomeras et al, 2014), as well as by potential field modeling (Bergamín and Carbó, 1986;Sentre Domingo et al, 2014;García-Lobón et al, 2014;Ehsan et al, 2015). Finally, we explore the inclusion of the gravity models into the conceptual model of Shin et al (2012) for the basaltic magmatism occurring in an intraplate, compressive regime.…”

Section: Introductionmentioning

confidence: 99%

Gravity modeling of the lithosphere in the Calatrava Volcanic Province (Spain): geodynamic implications.

Granja-Bruña

Vegas²,

Domingo

et al. 2015

Journal of Iberian Geology

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(M.A.S.D.); amunoz@ucm.es (A.M.M.); ssainz-maza@fomento.es (S.S.M.A)Received: 12 January 2015 / Accepted: 5 July 2015 / Available online: 20 July 2015 AbstractThe origin of the intraplate volcanism in the Calatrava Volcanic Province (CVP) is controversial. On the basis of its geochemical signature, it has been ascribed to an "aborted" rift, implying lithospheric thinning. However, the volcanism occurred during the generalized Cenozoic NW−SE-oriented compressive tectonic regime. On the other hand, on the basis of evidence for its deep-seated origin, it has been linked to the existence of a baby-plume detached from an active megaplume below the Canary-Azores Islands and the western Mediterranean. In order to understand better the aforementioned geodynamic scenarios for the origin of the CVP, we address here the study of the lithosphere in the CVP and its vicinity by means of gravity analysis and 2+1/2D modeling. Gravity modeling results do not support the rifting model adopted for the intraplate volcanism occurred in the CVP because the crust shows a quasi-constant thickness. Density models suggest the existence of a sub-crustal, anomalous low-density block that could be underplated magmatic material at the base of the crust, suggesting that only a minor part of it intruded up into the crust and erupted. The localized magmatism of the CVP can be related to the combination of two factors: active, the gentle folding of the Iberian lithosphere and associated uplifting of the Variscan basement due to the NW-directed transmission of compressive stresses in the upper plate yielded by the subduction/collision in the south Iberian margin. The formation of the lithospheric folding in the Calatrava region results in a decrease of the pressure beneath the swell of the antiform that is likely to bring about basaltic magmatism below the swell; and one passive, the existence of a Variscan right-lateral shear band, which yields a weakened crust that facilitates the ascent of the magmatic materials. The relatively small volume, but large extension, of the volcanic outcrops could be associated with the preferential ascent of the magmas along the weakened crust of this NW−SE-trending Variscan shear band.Keywords: Calatrava, intraplate volcanism, gravity modeling, lithosphere structure, upward continuation Resumen El origen del volcanismo intraplaca en la Provincia Volcánica de Calatrava (CVP) es controvertido. En base a su signatura geoquímica se ha atribuido a la formación de un rift "abortado", implicando un adelgazamiento litosférico. Sin embargo, el volcanismo se desarrolló durante un régimen tectónico compresivo orientado NW-SE que fue generalizado en la región de Calatrava durante el Cenozoico. Por otro lado, en base a las evidencias de su origen profundo, se le ha relacionado con la existencia de una mini-pluma desconectada de una mega-pluma activa debajo de los archipiélagos de Canarias y Azores, y en el Mediterráneo occidental. Con el propósito de contribuir a la discriminación entre los escenarios geodinámicos mencionados...

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Imaging the crustal structure of the Central Iberian Zone (Variscan Belt): The ALCUDIA deep seismic reflection transect

Cited by 48 publications

References 83 publications

Crustal thickness and images of the lithospheric discontinuities in the Gibraltar arc and surrounding areas

Crustal thickness and images of the lithospheric discontinuities in the Gibraltar arc and surrounding areas

Crustal structure and evolution of the Pyrenean-Cantabrian belt: A review and new interpretations from recent concepts and data

Gravity modeling of the lithosphere in the Calatrava Volcanic Province (Spain): geodynamic implications.

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