Continuous deformation, ductile thrusting and backfolding of cover and basement in the Sierra de Guadarrama, Hercynian orogen of central Spain

Macaya, Javiera Fernanda Medina; González-Lodeiro, Francisco; Martínez-Catalán, J. R.; Alvarez, Fernando Corzo

doi:10.1016/0040-1951(91)90063-x

Cited by 41 publications

(35 citation statements)

References 15 publications

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“…After D3 upright folding and D4 localized flattening about domal structures occurred under M3, LP/HT conditions, D4 (or regionally equivalent) extensional shear bands with strike-slip components (Hernandez Enrile, 1991;Macaya et al, 1991;Martlnez et al, 1996;Valle Aguado et al, 2005) completed emplacement of the allochthonous slab and exhumation of the high-grade rocks of the orogenic root.…”

Section: Discussionmentioning

confidence: 99%

“…metamorphism even at relatively deep structural levels. The absence of large recumbent folds or nappes associated with crustal thickening stages in the Central Iberian Zone, has raised questions about the mech anism that was responsible for deep burial of rocks, Barrovian meta morphism and subsequent metamorphic and igneous processes (Escuder Viruete et al, 1994;Macaya et al, 1991;Martlnez et al, 1988).…”

Section: Geological Setting and Tectonic Unitsmentioning

confidence: 99%

“…Early Ordovician felsic metavolcanic rocks (Gebauer et al, 1993;Montero et al, 2007;Valverde-Vaquero and Dlll1ning, 2000) of the Ollo de Sapo Formation occur at or near its base. An Sl foliation, axial planar to F1, and E-vergent folds, are well preserved above the D2 shear zone (Escuder Viruete et al, 1998;Macaya et al, 1991). Barrovian metamorphic zones (M1) were folded by D3 (Martfnez Catalan et al, 2007), but do not exhibit major low pressure (M3) overprinting, except for areas adjacent to the high grade dome (Fig.…”

Section: Geological Setting and Tectonic Unitsmentioning

confidence: 99%

“…However, some cross-cutting narrow shear bands and most of the NW part of the metamorphic dome have top-to-the-NW shear-sense as indi cated by s-c fabrics and NW-vergent F2 recumbent folds with their axes oriented perpendicular to stretched pebbles and ichnofossils defining U. The lowermost part of the Lower Unit presents an early syn-02 migmatitic foliation which is finally affected by the BSZ and by other low angle SE-and NW-directed mylonitic bands (Ooblas et al, 1994;Macaya et al, 1991). A few late-to post-02 thrusts locally emplaced high-grade rod{s of the Lower Unit, presently preserved as klippen, to wards the ESE upon the Middle Unit.…”

Section: Tectonic Evolutionmentioning

confidence: 99%

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Thickening and exhumation of the Variscan roots in the Iberian Central System: Tectonothermal processes and 40Ar/39Ar ages

et al. 2013

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Section: Discussionmentioning

confidence: 99%

Section: Geological Setting and Tectonic Unitsmentioning

confidence: 99%

Section: Geological Setting and Tectonic Unitsmentioning

confidence: 99%

Section: Tectonic Evolutionmentioning

confidence: 99%

See 2 more Smart Citations

Thickening and exhumation of the Variscan roots in the Iberian Central System: Tectonothermal processes and 40Ar/39Ar ages

et al. 2013

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“…1), which is the southern branch of the Ibero-Armorican arc, in the Variscan belt of western Europe. This internal orogenic area is characterized by the development of high-grade plutono-metamorphic complexes of regional scale and often dome-like geometry (Martínez et al 1988) that, internally, generally consist of imbricate stacks of orthogneiss and metasediment slices (Macaya et al 1991). The high-grade domes are surrounded by more simple and contrasting tectonic epizonal-anchimetamorphic domains, with very continuous but not strongly flattened subvertical or NE-vergent folds (Díez Balda et al 1990Balda et al , 1995.…”

Section: Introductionmentioning

confidence: 99%

Relationships between structural units in the Tormes gneiss dome (NW Iberian massif, Spain): geometry, structure and kinematics of contractional and extensional Variscan deformation

Viruete

1998

Geologische Rundschau

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Situated in the inner zone of the Iberian massif, the Tormes gneiss dome is composed of two units with different lithological contents and metamorphic evolution. The upper unit consists of a thick sequence of low-to highgrade metasediments, ranging in age from Late Proterozoic to Silurian. The lower unit is a high-grade metamorphic complex composed mostly of granitic orthogneisses and minor amounts of metasediments. Four Variscan deformations are distinguished. At deep structural levels, the most prominent D1 ductile structures are recumbent anticlines with NE vergence, cored by orthogneisses, and separated by narrow synclines. These recumbent folds grade upward into less-flattened and NE-vergent steeper structures. The overall structure is that of a large-scale stacking of orthogneissic slices underlying a shortened and thickened sedimentary sequence that formed a huge orogenic wedge in this region. During the heterogeneous and ductile D2 deformation, the rheological behaviour of the orthogneisses and metasediments became similar. The vertical D2 shortening associated with a strong top-to-the-SE shearing in a large-scale subhorizontal shear zone folded the prior SWdipping structures, developing SW-vergent folds with axes close to NW-SE L2 mineral and stretching lineations. D2 corresponds to post-collisional crustal thinning following D1 crustal thickening. The D3 and D4 late structures are much more localized and occurred under retrograde conditions, but have a significant effect on the final geometry of the metamorphic complex. This sequence of contractional and extensional deformative events permits a tectonic interpretation in the framework of the dynamic wedge theory based on the evolution in the time of the stress configuration applied to a portion of the crust.

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The mid‐latitude hydrolaccolith of the Spanish Central System (Southern Europe): A top‐to‐bottom integration of geomatic, geophysical and sedimentary datasets for characterising a singular periglacial landform

Fernández‐Lozano,

Turu,

Carrasco

et al. 2023

Land Degrad Dev

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Permafrost study in the Spanish Central System (~41°N) has remained elusive in past decades. Although numerous periglacial features have been described, none has yielded conclusive information about the existence/distribution of permafrost across these mountains. This work focuses on integrating light detection and ranging and unmanned aerial vehicle data with geophysical methods and sedimentary records, along with preliminary thermal information, for the comprehensive study of a frost mound. The singularity of this feature resides in its location, currently dominated by a seasonal frost regime, and its size reaching 59 m long, 22.5 m wide and 4 m high, representing the largest landform of this type in Iberia. From top‐to‐bottom, the internal structure comprises three resistivity units (G1, G2 and G3). The most superficial unit (G1) consists of a sequence of burial soils alternating with sand and silts, with pebbles and gravel at the bottom, followed by a high porous layer that belongs to a landslide deposit (G2), likely composed of gravel and pebbles laying over unit G3 (bedrock). Calibrated 14C ages suggest this landform formed at least ~4300 years ago during the mid‐Holocene. Finally, the preliminary surface thermal map indicates the presence of sectors affected by strong thermal gradients likely driven by water table variations. Our results conclude that the dynamics are primarily controlled by the seasonal frost regime influencing local subsurface drainage, which allows us to classify this landform as a hydrodynamic pingo‐like structure. We also demonstrate that our approach is suitable for assessing the evolution of this type of periglacial landform. Implementing long‐lasting annual monitoring programmes would help to understand local periglacial dynamics better.

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Continuous deformation, ductile thrusting and backfolding of cover and basement in the Sierra de Guadarrama, Hercynian orogen of central Spain

Cited by 41 publications

References 15 publications

Thickening and exhumation of the Variscan roots in the Iberian Central System: Tectonothermal processes and 40Ar/39Ar ages

Thickening and exhumation of the Variscan roots in the Iberian Central System: Tectonothermal processes and 40Ar/39Ar ages

Relationships between structural units in the Tormes gneiss dome (NW Iberian massif, Spain): geometry, structure and kinematics of contractional and extensional Variscan deformation

The mid‐latitude hydrolaccolith of the Spanish Central System (Southern Europe): A top‐to‐bottom integration of geomatic, geophysical and sedimentary datasets for characterising a singular periglacial landform

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