Evolution of the South-Iberian paleomargin: From hyperextension to continental subduction

Pedrera, Antonio; Ruíz-Constán, Ana; García-Senz, Jesús; Azor, António; Marín‐Lechado, Carlos; Ayala, C.; Neira, José Alberto Díaz de; Rodrı́guez-Fernández, L.

doi:10.1016/j.jsg.2020.104122

Cited by 47 publications

(63 citation statements)

References 127 publications

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“…The palaeo-thermal structure in the HT-metamorphism zone in the Nieves Unit showing an obliquity of isograds with the contact also reinforces our extensional emplacement model. The proposed extensional setting with mantle exhumation fits the observations of Pedrera et al (2020) with sheared peridotite bodies embedded in Triassic sediments and is similar to what is generally expected from the pre-orogenic setting of the Betics corresponding to a former oblique and segmented system between the Central Atlantic and the Western Tethys (Leprêtre et al, 2018;Fernàndez et al, 2019;Angrand et al, 2020;Pedrera et al, 2020).…”

Section: Significance Of the Ronda Peridotites-nieves Unit Contact Thrust Or Extensional Detachment?supporting

confidence: 81%

“…Proposed ages range from the early Permian (Rossetti et al, 2020;Acosta-Vigil et al, 2014) to the Jurassic (Michard et al, 1991;Sanchez-Rodriguez et al, 1996), the Late Oligocene or Early Miocene (Précigout et al, 2013;Frasca et al, 2017;Gueydan et al, 2019). Recent models also propose a Mesozoic hyperextension and mantle exhumation within the segmented rift system between Iberia and Africa (Fernàndez et al, 2019;Pedrera et al, 2020). The main reason for this lack of consensus is the clustering of most radiometric ages at ca.…”

Section: Mantle Exhumationmentioning

confidence: 99%

“…The second solution is then to consider that the peridotite had been exhumed much earlier during the Mesozoic up to the surface or the sea bottom, as envisaged in van Hinsbergen et al (2014) or Pedrera et al (2020), thus explaining the progressive decrease of temperature along the contact and the formation of ophicalcites. This exhumed peridotite together with the Jubrique Unit and its cover (Nieves unit) would then have been buried to middle crustal conditions during the Mesozoic by sedimentation above and then involved in the fast overthrusting event and exhumed at ∼20 Ma.…”

Section: New 40mentioning

confidence: 99%

“…Précigout et al, 2013;Frasca et al, 2016;Gueydan et al, 2019) and soon later obducted on the margin of Iberia, together with the associated lower crustal units. The second interpretation is that the mantle was exhumed up to upper crustal conditions much earlier in the Mesozoic or even the late Paleozoic (Kornprobst and Vielzeuf, 1984;Michard et al, 1991;Sánchez-Rodríguez and Gebauer, 2000;van Hinsbergen et al, 2014;Bessière, 2019;Rossetti et al, 2020;Pedrera et al, 2020). In the latter situation, the region where the mantle has been exhumed would be a part of the wide hyper-extended domain between Africa and Iberia, or between a proto-Alboran block and Iberia.…”

Section: Paleogeographymentioning

confidence: 99%

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Lateral variations of pressure-temperature evolution in non-cylindrical orogens and 3-D subduction dynamics: the Betic-Rif Cordillera example

Bessière

Jolivet²,

Augier

et al. 2021

Preprint

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Orogens closely linked to 3-D subduction dynamics are frequently non-cylindrical and the Mediterranean region is a perfect natural laboratory to observe several of them, as well as their interactions. Through the succession of extension, subduction and sometimes collision events, the kinematic reconstructions of such orogens can be difficult and the subject of active debates. The internal zones are often non-consensual, especially when their long-term Pressure-Temperature-time-deformation (P-T-t-d) evolutions are studied. This complexity is mostly due to pre-orogenic inheritance or complex interactions between the subducting lithosphere, the overriding plate and the asthenosphere. All these elements are described and documented in Mediterranean orogens, i.e., a complex shape of the Eurasian and African margins in pre-orogenic times and a complex slab retreat and tearing dynamics. Their 3-D geometry results in strongly arcuate belts, such as the Betic-Rif Cordillera, located in the westernmost part of the Mediterranean region.Focused on the Internal Zones of the Betic-Rif Cordillera and based on recent findings (Orogen Project framework), a synthesis of the tectono-metamorphic evolution shows the relations in space and time between tectonic and P-T evolutions. The reinterpretation of the contact between peridotite massifs and Mesozoic sediments as an extensional detachment leads to a discussion of the geodynamic setting and timing of mantle exhumation. Based on new 40Ar/39Ar ages in the Alpuj&#225;rride Complex (metamorphic formations of the Betic Internal Zones) and a discussion of published ages in the Nevado-Filabride Complex (metamorphic formations of the Betic Internal Zones), we conclude that the age of the HP-LT metamorphism is Eocene in all the Internal Zones. A first-order observation is the contrast between the well-preserved Eocene HP-LT blueschists-facies rocks of the Eastern Alpuj&#225;rride-Sebtide Complex and the younger HT-LP conditions reaching partial melting recorded in the Western Alpuj&#225;rride. We propose a model where the large longitudinal variations in the P-T evolution are mainly due to (i) differences in the timing of subduction and exhumation, (ii) the nature of the subducting lithosphere and (iii) a major change in subduction dynamics at ~20 Ma associated with a slab-tearing event.

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Section: Significance Of the Ronda Peridotites-nieves Unit Contact Thrust Or Extensional Detachment?supporting

confidence: 81%

Section: Mantle Exhumationmentioning

confidence: 99%

Section: New 40mentioning

confidence: 99%

Section: Paleogeographymentioning

confidence: 99%

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Lateral variations of pressure-temperature evolution in non-cylindrical orogens and 3-D subduction dynamics: the Betic-Rif Cordillera example

Bessière

Jolivet²,

Augier

et al. 2021

Preprint

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“…1). In this entirely eclogitic complex (Santamaria-López et al, 2019), the lowest unit is regarded as proximal with respect to the Iberian plate (e.g., Augier et al, 2005;Rodríguez-Cañero et al, 2018;Pedrera et al, 2020) whereas the overlying meta-ophiolites are considered to record a lost oceanic branch of the western Tethys, i.e., the Betic Ocean (Puga, 1990;Puga et al, 2005;Fig. 2) or West Ligurian Ocean (Leprêtre et al, 2018).…”

Section: Geological Settingmentioning

confidence: 99%

The Beni Bousera marbles, record of a Triassic-Early Jurassic hyperextended margin in the Alpujarrides-Sebtides units (Rif belt, Morocco)

Farah

Michard

Saddiqi

et al. 2021

BSGF - Earth Sci. Bull.

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The timing and process of exhumation of the subcontinental peridotites of the Gibraltar Arc (Ronda, Beni Bousera) have been repeatedly discussed in the last decades. Here we report on high-grade marbles that crop out around the central and southeastern parts of the Beni Bousera antiform of northern Rif. Instead of being mere intercalations in the granulitic envelope (kinzigites) of the peridotites, as currently admitted, they are localized between the kinzigites and the gneisses of the overlying Filali Unit. The marbles occur in the form of minor, dismembered units in a ~30 to 300 m-thick Filali-Beni Bousera ductile shear zone (FBBSZ). They display silicate-rich dolomitic marbles, sandy-conglomeratic calcareous marbles and thinly bedded marble with interleaved phyllites, which demonstrates their sedimentary origin. A stratigraphic or tectonic unconformable contact onto the kinzigites can be locally observed. Pebbles or detrital grains include K-feldspar, quartz, and zircon. Prograde metamorphic minerals are forsterite, Mg-Al-spinel, geikielite, phlogopite, scapolite, diopside, and titanite, which characterize a peak HT-LP metamorphism close to 700-750°C, 4-7 kbar, comparable to that of the overlying Filali gneisses and of the late migmatitic stage of the kinzigites. Second-order structures within the FBBSZ are northwestward ductile thrusts, which determine kinzigite horses thrust over the marbles. Within the latter, NNE-trending folds are conspicuous. The mylonitic structures are crosscut by late, northward dipping normal faults. Varied correlations with comparable settings in the other West Mediterranean Alpine belts are discussed. We propose to correlate the Beni Bousera marbles with the Triassic carbonates deposited over the crustal units of the Alpujarrides-Sebtides. The Triassic protoliths may have been deposited onto the kinzigites or carried as allochthons over a detachment during the Early Jurassic in the frame of the hyper-extension of the Alboran Domain continental crust, as observed in the Adria and Europe inverted margins of the Western Alps. In either of these hypotheses, the currently prevailing paradigm of “hot” exhumation of the Rif–Betic peridotites during the Alpine orogeny would be reconsidered.

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Refined tectonic evolution of the Betic-Rif orogen through integrated 3-D microstructural analysis and Sm-Nd dating of garnet porphyroblasts

Aerden

Farrell

Baxter

et al. 2021

Preprint

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The detailed deformation history of the Betic-Rif orogen (Figure 1) and its relationship with distinct metamorphic events recognized in this belt are still ambiguous as is reflected in disparate tectonic models that still differ on such fundamental aspects as the timing and polarity of subduction zones, the role of crustal extension versus compression, or the emplacement history of several peridotite massifs exposed in the belt (e.g.

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Evolution of the South-Iberian paleomargin: From hyperextension to continental subduction

Cited by 47 publications

References 127 publications

Lateral variations of pressure-temperature evolution in non-cylindrical orogens and 3-D subduction dynamics: the Betic-Rif Cordillera example

Lateral variations of pressure-temperature evolution in non-cylindrical orogens and 3-D subduction dynamics: the Betic-Rif Cordillera example

The Beni Bousera marbles, record of a Triassic-Early Jurassic hyperextended margin in the Alpujarrides-Sebtides units (Rif belt, Morocco)

Refined tectonic evolution of the Betic-Rif orogen through integrated 3-D microstructural analysis and Sm-Nd dating of garnet porphyroblasts

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