Wealth of P–T–t information in medium-high grade metapelites: Example from the Jubrique Unit of the Betic Cordillera, S Spain

Massonne, Hans‐Joachim

doi:10.1016/j.lithos.2014.08.027

Cited by 73 publications

(96 citation statements)

References 65 publications

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“…Among all the previously reported peak P for these rocks, including classical thermobarometic and phase equilibria modeling calculations (Loomis 1972;Torres-Roldán 1981;Balanyá et al 1997;Argles et al 1999;Platt et al 2003;Barich et al 2014;Massonne 2014), we have chosen the upper value of 1.5 GPa provided by most of these studies, expecting that this imposed external P on the Grt chips would prevent decrepitation of included MI due to increase in their internal P upon heating (e.g. Bartoli et al 2013a).…”

Section: P-t Conditions Of Anatexis At Jubriquementioning

confidence: 94%

“…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). This contribution focuses on MI in Grt of mylonitic, former high P granulitic metasedimentary migmatites from the Jubrique Alpujárride unit.…”

Section: Geological Settingmentioning

confidence: 98%

“…Zeck et al 1989;Platt et al 2013). Conversely, schist, migmatites and mylonitic gneisses are preCarboniferous and represent a polymetamorphic basement affected by at least the Variscan and Alpine orogenies (Montel et al 2000;Whitehouse and Platt 2003;Rossetti et al 2010;Massonne 2014). Rocks from all levels in the crustal section seem to record nearly isothermal decompression paths, from 1.4-1.2 kbar to 0.6-0.4 GPa at 750-850 ºC in the case of the mylonitic gneisses located at the contact with the Ronda peridotites (Torres-Roldán 1981;Argles et al 1999;Platt et al 2003;Barich et al 2014).…”

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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Section: P-t Conditions Of Anatexis At Jubriquementioning

confidence: 94%

Section: Geological Settingmentioning

confidence: 98%

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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“…2.5 wt.%) or oxygen contents (despite the aforementioned negligance of O 2 ) have been explored resulting in minor changes of the pseudosection topology (e.g. magnetite occurrence, small T shift of the solidus, see also Massonne, 2014), with no significant changes in the considered phase-in boundaries (e.g. cordierite-in; K-feldspar-in) unless too low water amounts are assumed, stabilizing K-feldspar (not observed) in subsolidus assemblages (e.g.…”

Section: P-t Estimatesmentioning

confidence: 99%

“…cordierite-in; K-feldspar-in) unless too low water amounts are assumed, stabilizing K-feldspar (not observed) in subsolidus assemblages (e.g. Massonne, 2014).…”

Section: P-t Estimatesmentioning

confidence: 99%

Pressure–temperature–time–deformation path of kyanite-bearing migmatitic paragneiss in the Kali Gandaki valley (Central Nepal): Investigation of Late Eocene–Early Oligocene melting processes

Iaccarino

Montomoli

Carosi

et al. 2015

Lithos

Self Cite

110

119

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Kyanite-bearing migmatitic paragneiss of the lower Greater Himalayan Sequence (GHS) in the Kali Gandaki transect (Central Himalaya) was investigated. In spite of the intense shearing, it was still possible to obtain many fundamental information for understanding the processes active during orogenesis. Using a multidis- ciplinary approach, including careful meso- and microstructural observations, pseudosection modelling (with PERPLE_X), trace element thermobarometry and in situ monazite U–Th–Pb geochronology, we constrained the pressure–temperature–time–deformation path of the studied rock, located in a structural key position. The migmatitic gneiss has experienced protracted prograde metamorphism after the India–Asia colli- sion (50–55 Ma) from ~43 Ma to 28 Ma. During the late phase (36–28 Ma) of this metamorphism, the gneiss underwent high-pressure melting at “near peak” conditions (710–720 °C/1.0–1.1 GPa) leading to kyanite- bearing leucosome formation. In the time span of 25–18 Ma, the rock experienced decompression and cooling associated with pervasive shearing reaching P–T conditions of 650–670 °C and 0.7–0.8 GPa, near the sillimanite–kyanite transition. This time span is somewhat older than previously reported for this event in the study area. During this stage, additional, but very little melt was produced. Taking the migmatitic gneiss as representative of the GHS, these data demonstrate that this unit underwent crustal melting at about 1 GPa in the Eocene–Early Oligocene, well before the widely accepted Miocene decompressional melting related to its extrusion. In general, kyanite-bearing migmatite, as reported here, could be linked to the production of the high-Ca granitic melts found along the Himalayan belt

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Oligo-Miocene thinning of the Beni Bousera peridotites and their Variscan crustal host rocks, Internal Rif, Morocco

Gueydan

Pitra

Afiri³

et al. 2015

Tectonics

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Deciphering Variscan versus Alpine history in the Internal Rif system is a key to constrain the tectonic evolution of the Alboran domain and hence the geodynamics of the western Mediterranean system during the Cenozoic. This study focuses on the evolution of the metamorphic envelope of the Beni Bousera massif and its relation to the underlying peridotites. Combining structural geology, metamorphic petrology, and laser ablation inductively coupled plasma mass spectrometry U-Th-Pb dating of monazite, this study contributes to the understanding of the tectonic history of the western Internal Rif. The regional foliation (S2) is characterized by low pressure-high temperature (LP-HT) mineral assemblages and obliterates a former foliation (S1) developed along a Barrovian (medium pressure-medium temperature, MP-MT) metamorphic gradient. The dating of some metamorphic monazite grains from a micaschist and a migmatitic gneiss demonstrates that the crustal envelope of the peridotite recorded two distinct tectonometamorphic episodes. Data from monazite inclusions in S1 garnet suggest that the first event, D1, is older than 250-170 Ma and likely related to the Variscan collision, in agreement with the Barrovian type of the metamorphic gradient. The second event, D2, is Alpine in age (at circa 21 Ma) and corresponds to a strong lithosphere thinning allowing subsequent subcontinental mantle exhumation. Such a tectonic context provides an explanation for the LP-HT metamorphic gradient that is recorded in the regional foliation of the western Betic-Rif system. This extension is probably related to a subduction slab rollback in the western end of the Mediterranean realm during the Oligo-Miocene times. No evidence for a Tertiary high pressure/low temperature metamorphism has been identified in the studied area.

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Wealth of P–T–t information in medium-high grade metapelites: Example from the Jubrique Unit of the Betic Cordillera, S Spain

Cited by 73 publications

References 65 publications

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

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

Pressure–temperature–time–deformation path of kyanite-bearing migmatitic paragneiss in the Kali Gandaki valley (Central Nepal): Investigation of Late Eocene–Early Oligocene melting processes

Oligo-Miocene thinning of the Beni Bousera peridotites and their Variscan crustal host rocks, Internal Rif, Morocco

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