Deformation and exhumation of the Ronda peridotite (Spain)

Précigout, Jacques; Gueydan, Frédéric; Garrido, Carlos J.; Cogné, Nathan; Booth‐Rea, Guillermo

doi:10.1002/tect.20062

Cited by 55 publications

(122 citation statements)

References 68 publications

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“…18). The peridotites were exhumed during Tertiary backarc rifting in the western Mediterranean and were thrust on top of the South Iberian passive margin soon after their exhumation, during the Miocene (Tubía et al, 1997;Mazzoli et al, 2013;Précigout et al, 2013;Johanesen and Platt, 2015). Figure 18a (Fig.…”

Section: Accepted Manuscript 31mentioning

confidence: 99%

Crustal versus mantle core complexes

et al. 2018

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This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. Contrary to what is commonly believed, it is argued from analogue and numerical models that detachments that accommodate exhumation of core complexes do not initiate at the onset of extension but in the course of progressive extension when the exhuming ductile crust reaches the surface. In models, convex upward detachments result from a rolling hinge process. A C C E P T E D M A N U S C R I P TMantle core complexes develop in either the oceanic lithosphere, at slow and ultra-slow spreading ridges, or in continental lithospheres, whose initial Moho temperature is lower than 750°C, with "sub-Moho mantle-dominated" strength profiles. It is argued that the mechanism of mantle exhumation at passive margins is a nearly symmetrical necking process at ACCEPTED MANUSCRIPTA C C E P T E D M A N U S C R I P T 2 lithosphere scale without major and permanent detachment, except if strong strain localization could occur in the lithosphere mantle. Distributed crustal extension, by upper crust faulting above a décollement along the ductile crust increases toward the rift axis up to crustal breakup.Mantle rocks exhume in the zone of crustal breakup accommodated by conjugate mantle shear zones that migrate with the rift axis, during increasing extension.

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Section: Accepted Manuscript 31mentioning

confidence: 99%

Crustal versus mantle core complexes

et al. 2018

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“…The metamorphic grade of the Alpujárride units increases from east to west in the orogen, such that in the western Betics granulitic migmatites occur at the base of the sequence and appear spatially associated with slices of subcontinental mantle peridotites (i.e. the Ronda peridotites ;Lundeen 1978;Obata 1980;Van der Wal and Vissers 1996;Garrido et al 2011;Précigout et al 2013). Thus, in the vicinity of the Ronda peridotites, crustal rocks show systematically the highest metamorphic grade and extensive melting (Loomis 1972;Torres-Roldán 1981Balanyá et al 1997;Tubía et al 1997Tubía et al , 2013Argles et al 1999;Acosta-Vigil et al 2001, 2014Platt et al 2003;Esteban et al 2008;Barich et al 2014).…”

Section: Geological Settingmentioning

confidence: 99%

“…All rocks in the sequence are affected by a penetrative foliation parallel to the lithological contacts, that may appear folded at the dm to m scale. The Ronda peridotites constitute a slab of subcontinental mantle up to 5-8 km thick (Ludeen 1978;Balanyá et al 1997;Torné et al 1992;Précigout et al 2013). …”

Section: Geological Settingmentioning

confidence: 99%

“…The mylonitic gneisses are in contact with the underlying Ronda peridotites along a high temperature ductile shear zone; this contact is parallel to the mylonitic foliation developed in both crustal and mantle rocks, and to the penetrative foliation and lithological contacts in the sequence (Balanyá et al 1997;Platt et al 2003;Garrido et al 2011;Précigout et al 2013). …”

Section: Geological Settingmentioning

confidence: 99%

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The composition of nanogranitoids in migmatites overlying the Ronda peridotites (Betic Cordillera, S Spain): the anatectic history of a polymetamorphic basement

Acosta-Vigil

Barich

Bartoli

et al. 2016

Contrib Mineral Petrol

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The study of the composition of primary melts during anatexis of high-pressure granulitic migmatites is relevant to understand the generation and differentiation of continental crust.Peritectic minerals in migmatites can trap dropless of melt that forms via incongruent melting reactions during crustal anatexis. These melt inclusions commonly crystallize and form nanogranitoids upon slow cooling of the anatectic terrane. To obtain the primary compositions of crustal melts recorded in these nanogranitoids, including volatile concentrations and information on fluid regimes, they must be remelted and rehomogenize before analysis. A new occurrence of nanogranitoids was recently reported in garnets of mylonitic metapelitic gneisses (former high pressure granulitic migmatites) at the bottom of the prograde metamorphic sequence of Jubrique, located on top of the Ronda peridotite slab (Betic Cordillera, S Spain). Nanogranitoids within separated chips of cores and rims of large garnets from these former migmatites were remelted at 15 kbar and 850, 825 or 800 ºC and dry (without added H 2 O), during 24 hours, using a piston cylinder apparatus. Although all experiments show glass (former melt) within melt inclusions, the extent of rehomogenization depends on the experimental temperature. Experiments at 850-825 ºC show abundant disequilibrium microstructures, whereas those at 800 ºC show a relatively high proportion of rehomogenized nanogranitoids, indicating that anatexis and entrapment of melt inclusions in these rocks was likely close to 800 ºC. Electron microprobe and NanoSIMS analyses show that experimental glasses are leucogranitoid and peraluminous, though define two distinct compositional groups. Type I corresponds to K-rich, Ca-and H 2 O-poor leucogranitic melts, whereas type II represents K-poor, Ca-and H 2 O-rich granodioritic to tonalitic melts. Type I and II melt inclusions are found in most cases at the cores and rims of large garnets, respectively. We tentatively suggest that these former migmatites underwent two melting events under contrasting fluid regimes, possibly during two different orogenic periods. This 3 study demonstrates the strong potential of melt inclusions studies in migmatites and granulites in order to unravel their anatectic history, particularly in strongly deformed rocks where most of the classical anatectic microstructures have been erased during deformation.

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“…Thus, previous works arguing for the exhumation of the peridotites in early Miocene, reflecting extensional collapse, include: Loomis (1975), Lundeen (1978), and Priem et al (1979), which are based mainly on K/Ar dating of rocks from the metamorphic aureole around the peridotites; the works of Doblas & Oyarzun (1989), Van der Wal & Vissers (1993), Vissers et al (1995), Tubía (1985Tubía ( , 1994, Tubía & Cuevas (1986, Tubía et al (1997;, Balanyá et al, (1993Balanyá et al, ( , 1997, Davies et al (1993), Sánchez Gómez et al (1995, Platt et al, 2003, Esteban et al (2011, Afiri et al (2011), and Garrido et al (2011), which used tectonic and petrological criteria derived from the study of peridotites and/or crustal rocks; the works of Zindler et al (1983) and Reisberg et al (1989), based on Sr and Nd isotopic data of clinopyroxenes; and works of Platt & Whitehouse (1999) and Sanchez-Rodriguez & Gebauer (2000), based on zircon dating of migmatitic rocks. Précigout et al (2013) deduced that the Ronda peridotites were emplaced during the OligoceneMiocene just before 22 Ma. Hidas et al (2013) proposed a model for the emplacement of the Ronda Peridotites in which folding and shearing of an attenuated mantle lithosphere occurred by back arc basin inversion during the late Oligocene and a later collision during the earliest Miocene.…”

Section: Introductionmentioning

confidence: 99%