Spectral analysis of the gravity and elevation along the western Africa–Eurasia plate tectonic limit: Continental versus oceanic lithospheric folding signals

Muñoz-Martı́n, A.; Muñoz, Gerardo de Vicente; Fernández-Lozano, Javier; Cloetingh, S.A.P.L.; Willingshofer, Ernst; Sokoutis, Dimitrios; Beekman, F.

doi:10.1016/j.tecto.2010.09.036

Cited by 22 publications

(22 citation statements)

References 58 publications

(92 reference statements)

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“…If there is a lithospheric thinning beneath the CVP, it should be small, below ≈10 km, and therefore outside the sensitivity of the gravity modeling. This observation is in agreement with the slope of the lithospheric folds in the continental crust of Iberia, which are very gentle: 1 -2 km of amplitude for wavelength of about 250 km (Muñoz-Martín et al, 2010). Such variations in the depth of the LAB are outside the sensitivity of our gravity modeling.…”

Section: Baby-plume Hypothesissupporting

confidence: 89%

“…2; Azor et al, 1994), which is a NW−SE-trending 5 km-wide band of high-grade metamorphics with slices of mafic rocks. The Alpine intraplate deformation of the Iberian Massif has been ascribed to crustal-scale buckling processes on the basis of numerical and analogue modeling (Cloetingh et al, 2002;Muñoz-Martín et al, 2010;Fernández-Lozano et al, 2012). This intraplate deformation has resulted from the N−Sdirected convergence of Africa and Eurasia during EoceneOligocene times and is responsible for the main topographic features in the Variscan basement of the Iberian Peninsula (De Vicente and Vegas, 2009).…”

Section: Tectonic Settingmentioning

confidence: 99%

“…The decompression beneath the lithosphere is likely to lead to basaltic magmatism along and below the swell of the antiform. Lithospheric folding of Iberia due to horizontal loading driven by the Alpine orogeny has been suggested from numerical and analogue modeling (e.g., Cloetingh et al, 2002;Muñoz-Martín et al, 2010;Fernández-Lozano et al, 2012). The topography of the center and western part of the Iberian Peninsula shows an alternation of E−W-to NE−SWtrending ridges and troughs that are the surface expression of a succession of crustal folds (i.e., succession of longwavelength anticlines and synclines) formed perpendicular to the main axis of present-day intraplate NW−SE-trending compression .…”

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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Section: Baby-plume Hypothesissupporting

confidence: 89%

Section: Tectonic Settingmentioning

confidence: 99%

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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“…The maximum axis M1 – M3 on the GIB approximately coincides with the morphological axis of the basin. The relative maximum axis M4 bordering the foot of the slope north of the SR and the relative minimum axis m2 and m3 on the BAP draw attention as they imply a lithospheric scale deformation, according to observations by Muñoz‐Martín et al ().…”

Section: Results and Interpretationmentioning

confidence: 90%

Crustal Structure and Continent‐Ocean Boundary Along the Galicia Continental Margin (NW Iberia): Insights From Combined Gravity and Seismic Interpretation

et al. 2018

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The magma-poor rifted continental margin of Galicia has an extremely complex structure. Its formation involved several rifting episodes that occurred ultimately during the early Cretaceous near a ridge triple junction, which produced a change in the orientation of the main structures in its transition to the north Iberia margin. In addition, there is a superimposed partial tectonic inversion along its northwest and northern border which developed from the Late Cretaceous to at least Oligocene times. The present study integrates a large volume of new geophysical information (mainly marine gravity data and 2-D seismic reflection profiles) to provide insights on the formation of this rift system and on the development of its later inversion. The combined interpretation and modeling of this data enable the presentation of a new crustal and structural domain map for the whole Galicia margin. This includes the rift domains related to the extreme thinning of the crust and the lithospheric mantle (stretched, necking, and hyperextension and mantle exhumation domains), as well as a domain of intense compressional deformation. New constraints arise on the origin, the deep structure, and the characterization of the along-and across-strike variation of the continent-ocean transition of the margin, where a progressive change from hyperextension to partial inversion is observed. The development of both rifting and later partial tectonic inversion is influenced by the existence of former first-order tectonic features. Most of the tectonic inversion is focused on the hyperextension and mantle exhumation domain, which in some areas of the northwestern margin is completely overprinted by compressional deformation.

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“…Topographic evolution of Iberia has largely been attributed to crustal thickening and by some to lithospheric‐scale buckling (e.g., Cloetingh et al, ; Muñoz‐Martín et al, ). There have been recent significant advances in our understanding of the crustal, lithospheric, and subplate structure beneath Iberia and its surroundings from seismology.…”

Section: Introductionmentioning

confidence: 99%

Neogene Epeirogeny of Iberia

Conway-Jones

Roberts

Fichtner

et al. 2019

Geochem Geophys Geosyst

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The origin of Iberia's topography is examined by combining gravity, magmatic, topographic, and seismological observations with geomorphic considerations. We have four principal results. First, the highest coherence between free-air gravity and topography is at wavelengths ≲250 km where admittance indicates that elastic thickness of Iberia's plate is 20 ± 3 km. These results imply that flexural and subplate support of Iberian topography could be expressed at wavelengths of O(100) km. Second, P-to-S receiver functions and simple isostatic calculations indicate that while crustal thickness variations and flexural loading (e.g., as a result of plate shortening) partially explain the elevation of Pyrenean, Betics, Cantabrian, Spanish Central System, and Iberian Chain topography, they fail to explain the elevation of large parts of Iberia. Third, a new full waveform shear wave tomographic model and velocity to temperature conversions suggest that the asthenosphere beneath Iberia is anomalously slow and has excess temperatures of up to 162 ± 14 • C. Simple isostatic calculations indicate asthenospheric support of topography of up to 1 km. Neogene-Recent (∼23-0 Ma) extrusive magmatism (e.g., Calatrava, Catalan) sit atop many of the slow shear wave velocity anomalies. Finally, biostratigraphic data, combined with inversion of 3,217 river profiles, show that most of Iberia's topography grew during the last ∼30 Ma at rates of up to 0.3 mm/year. Best-fitting theoretical rivers have a low residual root-mean-square misfit (= 0.96) and calculated uplift is consistent with an independent inventory of stratigraphic and biostratigraphic observations. We suggest that Neogene-Recent growth of most of central Iberia's topography was a result of asthenospheric support.

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Spectral analysis of the gravity and elevation along the western Africa–Eurasia plate tectonic limit: Continental versus oceanic lithospheric folding signals

Cited by 22 publications

References 58 publications

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

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

Crustal Structure and Continent‐Ocean Boundary Along the Galicia Continental Margin (NW Iberia): Insights From Combined Gravity and Seismic Interpretation

Neogene Epeirogeny of Iberia

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