Crustal deformation styles along the reprocessed deep seismic reflection transect of the Central Iberian Zone (Iberian Peninsula)

Ehsan, Siddique Akhtar; Carbonell, Ramón; Ayarza, P.; Martí, David; Pérez-Estaún, Andrés; Poyatos, D. Martínez; Simancas, José Fernando; Azor, António; Mansilla, Luis

doi:10.1016/j.tecto.2014.02.014

Cited by 25 publications

(56 citation statements)

References 54 publications

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“…These deep reflectors were interpreted as thrusts and fold belts, major faults and sometimes as mafic intrusions possibly associated with the VSC (Schmelzbach et al 2008b). Similar reflectivity patterns observed in another deep seismic reflection profile acquired over Palaeozoic terrains of the Central Iberian Zone have also been interpreted as imbricate thrust systems (Ehsan et al 2014).…”

Section: Integrated Interpretation and Geological Modellingsupporting

confidence: 65%

“…Kim et al 1994;Radzevicius and Pavlis 1999;Juhlin et al 2002;Juhlin and Stephens 2006;Eaton 2003;Schmelzbach et al 2007;Malehmir et al 2012a;Heinonen et al 2013;Ehsan et al 2014). The mining sector is one of the fields where the seismic reflection method has shown great utility to complement the more generally applied gravimetric, magnetic, electrical and electromagnetic methods.…”

Section: Introductionmentioning

confidence: 99%

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Subsurface mapping in the Iberian Pyrite Belt using seismic reflection profiling and potential-field data

Carvalho

Inverno

Matos

et al. 2016

Int J Earth Sci (Geol Rundsch)

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locations, were integrated in a 3D software environment along with potential-field, geological and drill-hole data to form a 3D structural framework model. Seismic data show strong reflections that represent several long Variscan thrust planes that smoothly dip to the NNE. Outcropping and previously unknown Late Variscan near-vertical faults were also mapped. Our data strongly suggest that the structural framework of Neves-Corvo extends south-eastwards to Alcoutim. Furthermore, the VSC top is located at depths that show the existence within the IPB of new areas with good potential to develop exploration projects envisaging the discovery of massive sulphide deposits of the NevesCorvo type.Abstract The Iberian Pyrite Belt (IPB) hosts world-class massive sulphide deposits, such as Neves-Corvo in Portugal and Rio Tinto in Spain. In Portugal, the Palaeozoic Volcanic-Sedimentary Complex (VSC) hosts these ore deposits, extending from the Grândola-Alcácer region to the Spanish border with a NW-SE to WNW-ESE trend. In the study area, between the Neves-Corvo mine region and Alcoutim (close to the Spanish border), the VSC outcrops only in a small horst near Alcoutim. Sparse exploration drill-hole data indicate that the depth to the top of the VSC varies from several 100 m to about 1 km beneath the Mértola Formation Flysch cover. Mapping of the VSC to the SE of Neves-Corvo mine is an important exploration goal and motivated the acquisition of six 2D seismic reflection profiles with a total length of approximately 82 km in order to map the hidden extension of the VSC. The data, providing information deeper than 10 km at some

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Section: Integrated Interpretation and Geological Modellingsupporting

confidence: 65%

Section: Introductionmentioning

confidence: 99%

Subsurface mapping in the Iberian Pyrite Belt using seismic reflection profiling and potential-field data

Carvalho

Inverno

Matos

et al. 2016

Int J Earth Sci (Geol Rundsch)

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“…The resulting landscape is characterized by narrow sierras overlying roughly Red-colored zones show the volcanic outcrops in the Calatrava Volcanic Province (Ancochea et al, 2004;Cebriá et al, 2011;Sentre Domingo et al, 2014). The dashed black lines show the approximate location of the deep seismic profiles: IBERSEIS (Palomeras et al, 2009), ALCU-DIA normal incidence (ALCUDIA-NI; Martínez Poyatos et al, 2012;Simancas et al, 2013;Ehsan et al, 2014) and ALCUDIA wide-angle (ALCUDIA-WA; Ehsan et al, 2015). SC= Sierra de la Calderina.…”

Section: Tectonic Settingmentioning

confidence: 99%

“…In the area of the Iberian Massif corresponding to the CVP, the southern part of the CIZ including the CU, the structure of the crust has been investigated by means of two deep seismic reflection profiles: the ALACUDIA normal-incidence profile (ALCUDIA-NI in Fig. 2; Martínez Poyatos et al, 2012;Simancas et al, 2013;Ehsan et al, 2014) and the AL-CUDIA wide-angle profile (ALCUDIA-WA in Fig. 2; Ehsan et al, 2015).…”

Section: Tectonic Settingmentioning

confidence: 99%

“…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%

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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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Crustal structure beneath the Rif Cordillera, North Morocco, from the RIFSIS wide‐angle reflection seismic experiment

Gil

Muset

Díaz

et al. 2014

Geochem Geophys Geosyst

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The different geodynamic models proposed since the late 1990s to account for the complex evolution of the Gibraltar Arc System lack definite constraints on the crustal structure of the Rif orogen. Here we present the first well-resolved P-wave velocity crustal models of the Rif Cordillera and its southern continuation toward the Atlas made using controlled-source seismic data. Two 3001 km-long wide-angle reflection profiles crossed the Rif along NS and EW trends. The profiles recorded simultaneously five land explosions of 1Tn each using 850 high frequency seismometers. The crustal structure revealed from 2-D forward modeling delineates a complex, laterally varying crustal structure below the Rif domains. The most surprising feature, seen on both profiles, is a 50 km deep crustal root localized beneath the External Rif. To the east, the crust thins rapidly by 20 km across the Nekkor fault, indicating that the fault is a crustal scale feature. On the NS profile the crust thins more gradually to 40 km thickness beneath Middle Atlas and 42 km beneath the Betics. These new seismic results are in overall agreement with regional trends of Bouguer gravity and are consistent with recent receiver function estimates of crustal thickness. The complex crustal structure of the Rif orogen in the Gibraltar Arc is a consequence of the Miocene collision between the Iberian and African plates. Both the abrupt change in crustal thickness at the Nekkor fault and the unexpectedly deep Rif crustal root can be attributed to interaction of the subducting Alboran slab with the North African passive margin at late Oligocene-early Miocene times.

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Crustal deformation styles along the reprocessed deep seismic reflection transect of the Central Iberian Zone (Iberian Peninsula)

Cited by 25 publications

References 54 publications

Subsurface mapping in the Iberian Pyrite Belt using seismic reflection profiling and potential-field data

Subsurface mapping in the Iberian Pyrite Belt using seismic reflection profiling and potential-field data

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

Crustal structure beneath the Rif Cordillera, North Morocco, from the RIFSIS wide‐angle reflection seismic experiment

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