The Getxo crustal-scale cross-section: Testing tectonic models in the Bay of Biscay-Pyrenean rift system

Pedrera, Antonio; García-Senz, Jesús; Peropadre, C.; Robador, Alejandro; López‐Mir, Berta; Díaz‐Alvarado, Juan; Rodrı́guez-Fernández, L.

doi:10.1016/j.earscirev.2020.103429

Cited by 20 publications

(31 citation statements)

References 112 publications

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“…Nevertheless, the higher Ti, Zr, Th, and Nb contents observed in the Cretaceous samples evidence an increase in the alkaline signature of the younger magmas. Similar geochemical evolutions have been described in coeval rift-related magmatism of the North Iberian plate margins (e.g., [95]).…”

Section: Variation Of Basaltic Melts and Mantle Sources Duringsupporting

confidence: 78%

Submarine Basaltic Magmatism in the Subbetic Basin (Southern Spain): Insights into Melt-Weakening Processes during Mesozoic Continental Rifting

Díaz‐Alvarado

Pedrera

Azor³

et al. 2021

Lithosphere

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Mantle-derived volcanic rocks from the Subbetic hyperextended basin in SE Spain provide new insights into the composition and mechanical behavior of the mantle during continental rifting. The present study describes a sequential restored cross-section along with geochemical characteristics of the basaltic rocks interbedded within the Mesozoic succession of the basin. Sedimentary stacking patterns of minibasins above the mobilized salt reflect the relationships with coeval basaltic volcanism. We recognize two type localities on the basis of volcanic facies, the presence of shallow intrusive bodies, and age of the associated sedimentary formations. The first type corresponds to subaqueous pillow-lava flows and subvolcanic sills and dikes associated with Lower Jurassic marly limestones and Middle Jurassic oolitic limestones. The Jurassic basalts present enriched MORB compositions with moderate La/Sm and low Sm/Yb ratios. Interestingly, a significant group of this Jurassic basaltic magmatism departs from the typical MORB-OIB array, showing deep Nb-Ta negative anomalies and high Th/Nb ratios. The second type comprises subaqueous lava flows, also including pillow-shaped basalts interlayered with hyaloclastite deposits and Upper Cretaceous clays, radiolarites, and marly limestones. The Cretaceous magmatism is characterized by highly enriched MORB compositions. Furthermore, the moderate Sm/Yb values and the positive correlation between LREE/HREE and Zr point to the involvement of deep (Grt-present) mantle sources in the origin of the Cretaceous basaltic melts. We interpret the Lower-Middle Jurassic calc-alkaline signal as due to the partial melting of recycled crustal rocks within the upper mantle, i.e., associated with remnants of pre-Mesozoic subducted slabs. These characteristics are similar to those described in Triassic basaltic rocks widespread throughout the External Zone of the Betic Cordillera. Mantle-derived basalts interlayered within the Lower Jurassic syn-rift deposits indicate that melting and deformation within the lithospheric mantle was initiated early during continental rifting. Accordingly, we suggest that Early to Middle Jurassic mantle melts promoted failure within the upper mantle, thus contributing to the inception of lithospheric-scale shear zones, which, in turn, controlled the evolution of this magma-poor hyperextended margin. Subsequently, rift evolution gave way to the activation of deeper melt sources in the mantle and an increase of the alkaline signature at the Cretaceous time.

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Section: Variation Of Basaltic Melts and Mantle Sources Duringsupporting

confidence: 78%

Submarine Basaltic Magmatism in the Subbetic Basin (Southern Spain): Insights into Melt-Weakening Processes during Mesozoic Continental Rifting

Díaz‐Alvarado

Pedrera

Azor³

et al. 2021

Lithosphere

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“…Thus, they suggest that erosion of basement and the volume of magmatic additions in the crust were minor. Note also that they show substantial differences to previously published lines from DeFelipe et al ( 2017), Pedrera et al (2021Pedrera et al ( , 2017. The restorations shown in Fig.…”

Section: Implications For Section Restorations Across the Pyrenean-cantabrian Domainscontrasting

confidence: 50%

The role of inheritance in forming rifts and rifted margins and building collisional orogens: a Biscay-Pyrenean perspective

Manatschal¹,

Chenin²,

Lescoutre³

et al. 2021

BSGF - Earth Sci. Bull.

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The aim of this paper is to provide a conceptual framework that integrates the role of inheritance in the study of rifts, rifted margins and collisional orogens based on the work done in the OROGEN project, which focuses on the Biscay-Pyrenean system. The Biscay-Pyrenean rift system resulted from a complex multistage rift evolution that developed over a complex lithosphere pre-structured by the Variscan orogenic cycle. There is a general agreement that the Pyrenean-Cantabrian orogen resulted from the reactivation of an increasingly mature rift system along-strike, ranging from a mature rifted margin in the west to an immature and segmented hyperextended rift in the east. However, different models have been proposed to explain the preceding syn-rift evolution and its influence on the subsequent reactivation. Results from the OROGEN project show a sequential reactivation of rift inherited decoupling horizons and identify the specific role of exhumed mantle, hyperextended and necking domains during reactivation. They also highlight the contrasting fate of segment centres vs. segment boundaries during convergence, explaining the non-cylindricity of internal parts of collisional orogens. Results from the OROGEN project also suggest that the role of inheritance is more important during the initial stages of subduction and collision, which may explain the complexity of internal parts of orogenic systems. In contrast, once tectonic systems get more mature, orogenic evolution becomes mostly controlled by first-order physical processes as described in the Coulomb Wedge theory for instance. This may account for the simpler and more continuous architecture of external parts of collisional orogens. It may also explain why most numerical models can reproduce mature orogenic and rift architectures with better accuracy compared to the initial stages of such systems. Thus, while inheritance may not explain steady-state processes, it is a prerequisite for comprehending the initial stages of tectonic systems. The new concepts developed from the OROGEN research are now ready to be tested at other orogenic systems that result from the reactivation of rifted margins, such as the Alps, the Colombian cordilleras and the Caribbean, Taiwan, Oman, Zagros or Timor.

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“…The rift axis is characterised by a succession of Upper Jurassic and Cretaceous sediments around 8-10 km thick with interlayered basic volcanic rocks of Aptian to Santonian age (Figure 8a,b; Azambre & Rossy, 1976;Castañares & Robles, 2004;Castañares et al, 1997;García Mondéjar et al, 1996;Rat, 1988;Rat et al, 1983). The lithosphere is extremely thin in the western central part of the basin, as suggested by a positive Bouguer anomaly recorded in the Biscay Synclinorium ( Figure 6; Pedreira et al, 2007) that is interpreted as the consequence of lithospheric mantle exhumed at shallow depth (Figure 8a,b; Garcia-Senz et al, 2019;Pedrera et al, 2017Pedrera et al, , 2020. Field observations and seismic interpretations indicate that the F I G U R E 7 Mauléon basin overall architecture.…”

Section: Basque-cantabrian Basinmentioning

confidence: 93%

Review of Iberia–Eurasia plate‐boundary basins: Role of sedimentary burial and salt tectonics during rifting and continental breakup

et al. 2021

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We document the role of sedimentary burial and salt tectonics in controlling the deformation style of continental crust during hyperextension. The Iberian-European boundary records a complex history of Cretaceous continental extension, which has led to the development of so-called smooth-slope type basins. Based on the review of the available geological constraints (crustal-balanced cross-sections, sedimentary profile evolution, RSCM thermometer, low-temperature thermochronology) and geophysical data (Bouguer anomaly, Moho depth, seismic reflection profiles and Vp/Vs velocity models) on the Tartas, Arzacq, Cameros, Parentis, Columbrets, Mauléon, Basque-Cantabrian and Internal Metamorphic Zone basins, we shed light on the main characteristics of this type of basin. This synthesis indicates that crustal thinning was influenced by two decoupling horizons: the middle crust and Triassic prerift salt, initially located between the basement and prerift sedimentary cover. These two horizons remained active throughout basin formation and were responsible for depth-dependent thinning of the crust and syn-rift salt tectonics. We therefore identify several successive deformation phases involving (a) pure shear dominated thinning, (b) simple shear dominated thinning and (c) continental breakup. In the first phase, distributed deformation resulted in the development of a symmetric basin. Field observations indicate that the middle and lower crust were under dominantly ductile conditions at this stage. In the second phase, deformation was localised along a crustal detachment rooted between the crust and the mantle and connecting upwards with Triassic prerift salt. During continental breakup, basin shoulders recorded the occurrence of brittle deformation, whereas the hyperextended domain remained under predominantly ductile thinning. The formation of smooth-slope-type extensional basins was intrinsically linked to the combined deposition of thick syn-rift and breakup sequences, and regional salt tectonics. They induced significant burial and allowed the continental crust and the prerift sequence to deform under high temperature conditions from the rifting to continental breakup stages.

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The Getxo crustal-scale cross-section: Testing tectonic models in the Bay of Biscay-Pyrenean rift system

Cited by 20 publications

References 112 publications

Submarine Basaltic Magmatism in the Subbetic Basin (Southern Spain): Insights into Melt-Weakening Processes during Mesozoic Continental Rifting

Submarine Basaltic Magmatism in the Subbetic Basin (Southern Spain): Insights into Melt-Weakening Processes during Mesozoic Continental Rifting

The role of inheritance in forming rifts and rifted margins and building collisional orogens: a Biscay-Pyrenean perspective

Review of Iberia–Eurasia plate‐boundary basins: Role of sedimentary burial and salt tectonics during rifting and continental breakup

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