A review of Alpine tectonics in Portugal: Foreland detachment in basement and cover rocks

Ribeiro, A.; Kullberg, María Carla; Kullberg, José Carlos; Manuppella, Giuseppe; Phipps, Stephen Paul

doi:10.1016/0040-1951(90)90448-h

Cited by 160 publications

(125 citation statements)

References 8 publications

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“…It later evolved to a transpressive foredeep basin during the Miocene, under a NNW-SSE to NW-SE compression that caused tectonic inversion of the extensional Mesozoic Lusitanian Basin (LB) located to the W (Fonseca 1989, Ribeiro et al 1990, Cabral 1995, Rasmussen et al 1998, Cabral et al 2003, Carvalho 2003, Carvalho et al 2016 (Figure 2).…”

Section: Seismotectonic Settingmentioning

confidence: 99%

“…50 km (Figure 2). It was generated in the Mesozoic as a normal fault zone of the LB (e.g., Rasmussen et al 1998, Kullberg 2000, Carvalho et al2005, and was later tectonically inverted, moving with oblique reverse-left lateral slip since the Neogene (Ribeiro et al 1990, Cabral et al 2003, Carvalho et al 20062008;. It outcrops north of Lisbon as a steep east-verging reverse fault placing Jurassic rocks of the LB, at the west, over Miocene deposits of Tortonian age, at the east.…”

Section: Seismotectonic Settingmentioning

confidence: 99%

“…Although being a blind structure, the PNAF has been recognized for quite a long time by subsurface information, mostly seismic reflection and borehole data for oil exploration. The available data evidence the occurrence of a wall of Lower Jurassic evaporites intruding the fault zone (e.g., Walker 1983, Ribeiro et al 1990), which shows a branched geometry, extending over a deformation zone up to 1.5 km wide (Cabral et al 2003, Moniz 2010, Moniz and Cabral 2014. It was generated as an extensional structure at the eastern border of the Mesozoic LB in this sector, and was later reactivated with left-lateral strike-slip motion in the Miocene (Ribeiro et al 1990).…”

Section: Seismotectonic Settingmentioning

confidence: 99%

“…The available data evidence the occurrence of a wall of Lower Jurassic evaporites intruding the fault zone (e.g., Walker 1983, Ribeiro et al 1990), which shows a branched geometry, extending over a deformation zone up to 1.5 km wide (Cabral et al 2003, Moniz 2010, Moniz and Cabral 2014. It was generated as an extensional structure at the eastern border of the Mesozoic LB in this sector, and was later reactivated with left-lateral strike-slip motion in the Miocene (Ribeiro et al 1990). The subsurface data show that the basal unconformity of the Pliocene sediments is folded and downthrown to the east, indicating late Neogene to Quaternary tectonic activity under the current stress field.…”

Section: Seismotectonic Settingmentioning

confidence: 99%

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Los terremotos del Bajo Valle del Tajo (Portugal): Lisboa 26 de Enero de 1531 y Benavente 23 de Abril de 1909

2017

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Abstract. The Lower Tagus Valley (LTV) has been the source of several local earthquakes that affected the region of Lisbon, in the central part of Portugal. In spite of absence of strong earthquakes during the last 100 years, past events have produced large damage in this area. We present the state of the art concerning the last two major earthquakes, which occurred in 1531 and 1909. The effects of both events are described, based on coeval reports already interpreted by several authors. The source parameters determined by different authors are also presented. The characterization of the seismogenic potential of the LTV is very important to better estimate the seismic hazard and risk of the region of Lisbon and Tagus Valley.

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Section: Seismotectonic Settingmentioning

confidence: 99%

Section: Seismotectonic Settingmentioning

confidence: 99%

Section: Seismotectonic Settingmentioning

confidence: 99%

Section: Seismotectonic Settingmentioning

confidence: 99%

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Los terremotos del Bajo Valle del Tajo (Portugal): Lisboa 26 de Enero de 1531 y Benavente 23 de Abril de 1909

2017

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“…1). It is a double vergence chain with thick-skin tectonics and a complex evolution during the Cenozoic (Vegas et al, 1990;Ribeiro et al, 1990;De Vicente et al, 1996;Andeweg et al 1999;De Vicente et al, 2007). The basement uplift extends for over 500 km toward the Atlantic coast, with an orientation ranging from E-W to NE-SW and an average width of ~80 km.…”

Section: The Central System and The Duero And Madrid Basinsmentioning

confidence: 99%

Strength of the Iberian intraplate lithosphere: Cenozoic deformations and seismicity

Martín-Velázquez

Muñoz

Gómez-Ortíz

et al. 2016

Journal of Iberian Geology

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Previous studies about the strength of the lithosphere in the center of Iberia fail to resolve the depth of earthquakes because of the rheological uncertainties. Therefore, new contributions are considered (the crustal structure from a density model) and several parameters (tectonic regime, mantle rheology, strain rate) are checked in this paper to properly examine the role of lithospheric strength in the intraplate seismicity and the Cenozoic evolution. The strength distribution with depth, the integrated strength, the effective elastic thickness and the seismogenic thickness have been calculated by a finite element modelling of the lithosphere across the Central System mountain range and the bordering Duero and Madrid sedimentary basins. Only a dry mantle under strike-slip/extension and a strain rate of 10 -15 s , causes a strong lithosphere. The integrated strength and the elastic thickness are lower in the mountain chain than in the basins. This heterogeneity has been maintained since the Cenozoic and determine the mountain uplift and the biharmonic folding of the Iberian lithosphere during the Alpine deformations. The seismogenic thickness bounds the seismic activity in the upper-middle crust, and the decreasing crustal strength from the Duero Basin towards the Madrid Basin is related to a parallel increase in Plio-Quaternary deformations and seismicity. However, elasto-plastic modelling shows that current African-Eurasian convergence is resolved elastically or ductilely, which accounts for the low seismicity recorded in this region.Keywords: lithospheric strength, effective elastic thickness, seismogenic thickness, Iberia, finite element modelling ResumenLos estudios previos sobre resistencia de la litosfera en el centro de Iberia no logran resolver la profundidad de los terremotos debido a las incertidumbres reológicas. Por eso, en este trabajo se han considerado nuevas contribuciones (estructura cortical obtenida de un modelo de densidad) y se han comprobado varios parámetros (régimen tectónico, reología del manto, tasa de deformación) para examinar adecuadamente el papel de la resistencia de la litosfera en la sismicidad intraplaca y en la evolución Cenozoica. Mediante una modelización de elementos finitos, se ha calculado la distribución de la resistencia con la profundidad, la resistencia integrada, el espesor elástico efectivo y el espesor sismogénico en una sección litosférica que atraviesa la cadena montañosa del Sistema Central y las cuencas sedimentarias del Duero y Madrid. Sólo un manto seco en desgarre/extensión y una tasa de deformación de 10 -15 s -1, o bajo extensión y 10 -16 s -1 , origina una litosfera resistente. La resistencia integrada y el espesor elástico son más bajos en el sistema montañoso que en las cuencas. Estas anisotropías se han mantenido desde el Cenozoico y determinan el levantamiento de la cadena y el plegamiento biarmónico de la litosfera Ibérica durante las deformaciones alpinas. El espesor sismogénico limita la actividad sísmica en la corteza superior-media, y l...

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Structures and geometries of the Tajo Basin crust, Spain: Results of a magnetotelluric investigation compared to seismic and thermal models

2014

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The Tajo Basin and Betic Mountain Chain in the south central region of the Iberian Peninsula were chosen for investigation in the first phase of the magnetotelluric (MT) component of the PICASSO (Program to Investigate the Convective Alboran Sea System Overturn) project. The MT results provide information about the electrical conductivity distribution in previously unprobed subsurface regions, as well as complimenting and enhancing results of prior geological and geophysical investigations thereby enabling the definition of a petrological subsurface model and a comprehensive understanding about the tectonic setting. Two‐dimensional (2‐D) inversion of the MT data provides enhanced insight into Iberian subsurface geology in the crust. The most striking features of the final model are (i) a distinct vertical interface within the Variscan basement beneath the center of the Tajo Basin that is spatially associated with the boundary between regions with and without substantial Alpine deformation, and (ii) a middle to lower crustal conductive anomaly that can be related to remnants of asthenospheric intrusion in connection with Pliocene volcanic events in the Calatrava Volcanic Province. For the latter, effects of hydrous phases are inferred that may originate from dehydration processes within the subducting slab beneath Alboran Domain and Betic Mountain Chain.

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A review of Alpine tectonics in Portugal: Foreland detachment in basement and cover rocks

Cited by 160 publications

References 8 publications

Los terremotos del Bajo Valle del Tajo (Portugal): Lisboa 26 de Enero de 1531 y Benavente 23 de Abril de 1909

Los terremotos del Bajo Valle del Tajo (Portugal): Lisboa 26 de Enero de 1531 y Benavente 23 de Abril de 1909

Strength of the Iberian intraplate lithosphere: Cenozoic deformations and seismicity

Structures and geometries of the Tajo Basin crust, Spain: Results of a magnetotelluric investigation compared to seismic and thermal models

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