Coexisting anorogenic and subduction-related metasomatism in mantle xenoliths from the Betic Cordillera (southern Spain)

Beccaluva, Luigi; Bianchini, Gianluca; Bonadiman, Costanza; Siena, Franca; Vaccaro, Carmela

doi:10.1016/j.lithos.2003.12.015

Cited by 113 publications

(71 citation statements)

References 54 publications

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“…However, studies of rocks from the upper mantle and experimental simulations of liquid migration in porous media have shown that liquid may ascend a partly molten rock column (e.g., peridotite) either through a pervasive porous flow or through a channelized flow (Kelemen et al 1995(Kelemen et al , 1997Ertan and Leeman 1996;Beccaluva et al 2004;Van Den Bleeken et al 2010). In the mantle wedge, whether the liquid migrates as a porous flow or as a channel flow depends on processes of reactive infiltration-dissolution (Daines and Kohlstedt 1994;Morgan and Liang 2003) and also on the grain size of the porous medium (Wark and Watson 2000).…”

Section: Insight From Plagioclase Compositional Profilesmentioning

confidence: 99%

Efficiency of compaction and compositional convection during mafic crystal mush solidification: the Sept Iles layered intrusion, Canada

Namur

Charlier

2012

Contrib Mineral Petrol

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Adcumulate formation in mafic layered intrusions is attributed either to gravity-driven compaction, which expels the intercumulus melt out of the crystal matrix, or to compositional convection, which maintains the intercumulus liquid at a constant composition through liquid exchange with the main magma body. These processes are length-scale and time-scale dependent, and application of experimentally derived theoretical formulations to magma chambers is not straightforward. New data from the Sept Iles layered intrusion are presented and constrain the relative efficiency of these processes during solidification of the mafic crystal mush. Troctolites with meso-to ortho-cumulate texture are stratigraphically followed by Fe-Ti oxide-bearing gabbros with adcumulate texture. Calculations of intercumulus liquid fractions based on whole-rock P, Zr, V and Cr contents and detailed plagioclase compositional profiles show that both compaction and compositional convection operate, but their efficiency changes with liquid differentiation. Before saturation of Fe-Ti oxides in the intercumulus liquid, convection is not active due to the stable liquid density distribution within the crystal mush. At this stage, compaction and minor intercumulus liquid crystallization reduce the porosity to 30%. The velocity of liquid expulsion is then too slow compared with the rate of crystal accumulation. Compositional convection starts at Fe-Ti oxide-saturation in the pore melt due to its decreasing density. This process occurs together with crystallization of the intercumulus melt until the residual porosity is less than 10%. Compositional convection is evidenced by external plagioclase rims buffered at An 61 owing to continuous exchange between the intercumulus melt and the main liquid body. The change from a channel flow regime that dominates in troctolites to a porous flow regime in gabbros results from the increasing efficiency of compaction with differentiation due to higher density contrast between the cumulus crystal matrix and the equilibrium melts and to the bottom-up decreasing rate of crystal accumulation in the magma chamber.

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Section: Insight From Plagioclase Compositional Profilesmentioning

confidence: 99%

Efficiency of compaction and compositional convection during mafic crystal mush solidification: the Sept Iles layered intrusion, Canada

Namur

Charlier

2012

Contrib Mineral Petrol

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“…Trace-element geochemistry [Keppler, 1996;Tatsumi and Kogiso, 1997;Beccaluva et al, 2004]. All samples also show negative Eu anomalies (0.38 < Eu/Eu* < 0.84).…”

Section: Alteration and Elemental Mobilitymentioning

confidence: 98%

Potassic late orogenic Stephanian volcanism in the Southwest French Massif central (Decazeville, Figeac, Lacapelle-Marival basins): an example for mantle metasomatism along strike-slip faults?

Lapierre¹,

Basile

Berly

et al. 2008

Bulletin De La Société Géologique De France

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In the southwestern part of the French Massif central (Decazeville basin, at the Sillon Houiller fault termination; Figeac and Lacapelle-Marival basins along the Argentat fault), Stephanian volcanism exhibits shoshonitic affinities. Their chondrite-normalized rare earth element (REE) patterns are enriched in light REE, but almost flat for heavy REE, with marked negative Eu anomalies. Primitive mantle-normalized element spectra show negative Nb, Ta, P, Sm, Ti, and positive Th, U, Pb anomalies, respectively. εNd values are negative and homogeneous (−6 to −4). This volcanism shares the same geochemical patterns as the late-orogenic Stephanian-Permian magmatism from the southern part of the Variscan belt (Pyrénées, Alps, Sardinia). We explain these geochemical characteristics as resulting from the partial melting of a metasomatised mantle. We propose a new mechanism to explain this melting process: horizontal displacement along the main late-orogenic strike-slip faults might bring into contact a hydrated lower crust with the lithospheric mantle. Mantle metasomatism within the strike-slip fault zone may then induce partial melting.

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“…Different metasomatic agents have been invoked in literature to explain the enriched composition of mantle xenoliths: mafic silicate melts (Zangana et al 1999;Gregoire et al 2000;Beccaluva et al 2001a, b), subduction-related fluids (Vaselli et al 1995;Zanetti et al 1999;Beccaluva et al 2004;Bianchini et al 2007) and carbonatitic melts (Yaxley et al 1998;Ionov et al 1996;Coltorti et al 1999;Beccaluva et al 2007;Beard et al 2007). …”

Section: Metasomatic Processesmentioning

confidence: 99%

“…Despite the presence in Sardinia of subduction-related igneous activity during CarboniferousPermian and Late Eocene-Middle Miocene times (e.g. Franciosi et al 2003;Morra et al 1997;Lustrino et al 2009), the hypothesis of a subduction-related metasomatism can be excluded, as typical fingerprints of subductionrelated metasomatism, such as strong enrichment in Rb, Sr, Ba (Zanetti et al 1999, 2004Downes 2001), high 87 Sr/ 86 Sr ratios (Downes 2001;Zanetti et al 1999;Beccaluva et al 2004 and references therein) and orthopyroxene-rich composition (e.g. Beccaluva et al 2004) are lacking.…”

Section: Metasomatic Processesmentioning

confidence: 99%

Petrological, geochemical and isotopic characteristics of the lithospheric mantle beneath Sardinia (Italy) as indicated by ultramafic xenoliths enclosed in alkaline lavas

Rocco

Lustrino

Morra

et al. 2011

Int J Earth Sci (Geol Rundsch)

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Mantle xenoliths hosted in Miocene-Quaternary mafic alkaline volcanic rocks from Sardinia have been investigated with electron microprobe, laser ablation microprobe-inductively coupled plasma-mass spectrometry and thermal ionization mass spectrometry techniques. The xenoliths are anhydrous clinopyroxene-poor lherzolites and harzburgites, plus very rare websterites and olivine-websterites. Glassy pods having thin subhedral to euhedral microlites of olivine, clinopyroxene and spinel have been found in harzburgites and websterites. Clinopyroxene shows trace element variability, with values of (La/Yb)(N) ranging from sub-chondritic (0.01) to supra-chondritic (8.6). The Sr-Nd isotopic ratios of the clinopyroxenes fall mostly in the field of the European lithospheric mantle xenoliths (Sr-87/Sr-86 from 0.70385 to 0.70568 and Nd-143/Nd-144 ranging from 0.512557 to 0.512953). The geochemical characteristics of the Sardinian xenoliths testify to the variable degrees of earlier partial melt extraction, followed by metasomatic modification by alkaline melts or fluids. Websterites are considered to represent small lenses or veins of cumulitic (i.e. magmatic) origin within the mantle peridotite

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Coexisting anorogenic and subduction-related metasomatism in mantle xenoliths from the Betic Cordillera (southern Spain)

Cited by 113 publications

References 54 publications

Efficiency of compaction and compositional convection during mafic crystal mush solidification: the Sept Iles layered intrusion, Canada

Efficiency of compaction and compositional convection during mafic crystal mush solidification: the Sept Iles layered intrusion, Canada

Potassic late orogenic Stephanian volcanism in the Southwest French Massif central (Decazeville, Figeac, Lacapelle-Marival basins): an example for mantle metasomatism along strike-slip faults?

Petrological, geochemical and isotopic characteristics of the lithospheric mantle beneath Sardinia (Italy) as indicated by ultramafic xenoliths enclosed in alkaline lavas

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