The origin of reaction textures in mantle peridotite xenoliths from Sal Island, Cape Verde: the case for “metasomatism” by the host lava

Shaw, Cliff S. J.; Heidelbach, Florian; Dingwell, Donald B.

doi:10.1007/s00410-006-0087-2

Cited by 87 publications

(70 citation statements)

References 27 publications

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“…The same holds for glasses and reaction textures in xenoliths, which are attributed to either mantle metasomatism or reaction with the entraining melt (e.g. Shaw et al 2006, and references therein).…”

Section: Comparison With Natural Quenched Liquidsmentioning

confidence: 91%

Melt variability in percolated peridotite: an experimental study applied to reactive migration of tholeiitic basalt in the upper mantle

Bleeken

Müntener

Ulmer³

2010

Contrib Mineral Petrol

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Melt-rock reaction in the upper mantle is recorded in a variety of ultramafic rocks and is an important process in modifying melt composition on its way from the source region towards the surface. This experimental study evaluates the compositional variability of tholeiitic basalts upon reaction with depleted peridotite at uppermost-mantle conditions. Infiltration-reaction processes are simulated by employing a three-layered set-up: primitive basaltic powder ('melt layer') is overlain by a 'peridotite layer' and a layer of vitreous carbon spheres ('melt trap'). Melt from the melt layer is forced to move through the peridotite layer into the melt trap. Experiments were conducted at 0.65 and 0.8 GPa in the temperature range 1,170-1,290°C. In this P-T range, representing conditions encountered in the transition zone (thermal boundary layer) between the asthenosphere and the lithosphere underneath oceanic spreading centres, the melt is subjected to fractionation, and the peridotite is partially melting (T s * 1,260°C). The effect of reaction between melt and peridotite on the melt composition was investigated across each experimental charge. Quenched melts in the peridotite layers display larger compositional variations than melt layer glasses. A difference between glasses in the melt and peridotite layer becomes more important at decreasing temperature through a combination of enrichment in incompatible elements in the melt layer and less efficient diffusive equilibration in the melt phase. At 1,290°C, preferential dissolution of pyroxenes enriches the melt in silica and dilutes it in incompatible elements. Moreover, liquids become increasingly enriched in Cr 2 O 3 at higher temperatures due to the dissolution of spinel. Silica contents of liquids decrease at 1,260°C, whereas incompatible elements start to concentrate in the melt due to increasing levels of crystallization. At the lowest temperatures investigated, increasing alkali contents cause silica to increase as a consequence of reactive fractionation. Pervasive percolation of tholeiitic basalt through an upper-mantle thermal boundary layer can thus impose a high-Si 'low-pressure' signature on MORB. This could explain opx ? plag enrichment in shallow plagioclase peridotites and prolonged formation of olivine gabbros.

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Section: Comparison With Natural Quenched Liquidsmentioning

confidence: 91%

Melt variability in percolated peridotite: an experimental study applied to reactive migration of tholeiitic basalt in the upper mantle

Bleeken

Müntener

Ulmer³

2010

Contrib Mineral Petrol

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“…The origin of both the glass films and pockets, and the associated reaction textures, has been a matter of considerable debate. Glass is interpreted to have formed by partial melting (Laporte et al 2006), infiltration of kimberlitelike melts and other metasomatizing agents (Schiano and Clocchiatti 1994;Bonadiman et al 2005), breakdown of amphibole (Shaw and Klügel 2002) and infiltration of silicaundersaturated host melts and reaction with xenolith minerals during excavation and transport from the mantle source (Shaw and Edgar 1997;Shaw et al 2006).…”

Section: Natural Samplesmentioning

confidence: 99%

“…Much of our understanding of the mantle is based on observations of depleted mantle xenoliths that have suffered variable degrees of melt extraction and enriched mantle xenoliths that have suffered enrichment by mantle metasomatism. However, several recent petrologic studies (Shaw and Klügel 2002;Shaw et al 2006) have shown that xenoliths may reside in crustal magma chambers for significant periods of time prior to eruption. During such residence periods, xenoliths are subject to significant textural modification through interaction between magma and xenolith minerals that may mimic the effects of mantle metasomatism.…”

Section: Introductionmentioning

confidence: 99%

Understanding the textures and origin of shock melt pockets in Martian meteorites from petrographic studies, comparisons with terrestrial mantle xenoliths, and experimental studies

Walton

Shaw

2009

Meteorit & Planetary Scien

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Abstract-We present a textural comparison of localized shock melt pockets in Martian meteorites and glass pockets in terrestrial, mantle-derived peridotites. Specific textures such as the development of sieve texture on spinel and pyroxene, and melt migration and reaction with the host rock are identical between these two apparently disparate sample sets. Based on petrographic and compositional observations it is concluded that void collapse/variable shock impedance is able to account for the occurrence of pre-terrestrial sulfate-bearing secondary minerals in the melts, high gas emplacement efficiencies, and S, Al, Ca, and Na enrichments and Fe and Mg depletion of shock melt compositions compared to the host rock; previously used as arguments against such a formation mechanism. Recent experimental studies of xenoliths are also reviewed to show how these data further our understanding of texture development and can be used to shed light on the petrogenesis of shock melts in Martian meteorites.

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“…Even, if we assume that amphibole completely broke down to olivine, clinopyroxene, spinel and glass ± rhönite (Aliani et al 2009;Shaw 2009;Ladenberger et al 2006b), the modelled composition of theoretical amphibole does not fit to composition of any of amphibole described in xenoliths from the Lower Silesia area (Matusiak-Małek et al 2010). Carpenter et al (2002) and Shaw et al (2006) suggested that formation of new clinopyroxene as spongy rims at the cost of the existing one effects from melting of the primary phase. In this scenario, Al and Na should decrease in the newly formed phase, whereas Ca should increase.…”

Section: Origin Of Intergranular Aggregates and Glassy Poolsmentioning

confidence: 96%

“…Several mechanisms of formation of such aggregates have been proposed in literature: (1) direct infiltration of the host magma Shaw and Dingwell 2008); (2) decomposition of hydrous phases (e.g. Aliani et al 2009;Shaw 2009); (3) melting of peridotite (Carpenter et al 2002;Shaw et al 2006) and (4) infiltration ofa meltat mantle depths (Shaw and Klügel 2002);…”

Section: Origin Of Intergranular Aggregates and Glassy Poolsmentioning

confidence: 99%

Lithospheric mantle beneath NE part of Bohemian Massif and its relation to overlying crust: new insights from Pilchowice xenolith suite, Sudetes, SW Poland

Ćwiek

Matusiak‐Małek

Puziewicz

et al. 2017

Int J Earth Sci (Geol Rundsch)

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The Oligocene/Miocene basanite from Pilchowice (Sudetes Mts., SW Poland) carries numerous small xenoliths of mantle peridotite, mostly harzburgite. The Pilchowice xenolith suite is dominated by harzburgites and dunites containing olivine Fo 90.2-91.5 (group A). The peridotites of group B (olivine Fo 88.6-89.4), and C (olivine Fo 83.2-86.5) are subordinate. The peridotites suffered from significant melt extraction (20-30%) and were subsequently subjected to metasomatism. Three different trace element compositional patterns of group A clinopyroxene occur, which are typical of silicate melt, carbonatite melt and silicate-carbonatite melt metasomatism, whereas groups B and C were affected by silicate melt metasomatism only. The Pilchowice basanite occurs at the contact of Karkonosze-Izera Block and Kaczawa Complex, two major geological units of Sudetes. The Pilchowice xenolith suite documents underlying lithospheric mantle of composition and depletion degree similar to those described in the whole Lower Silesian mantle domain, which forms NE termination of Saxo-Thuringian zone of the European Variscan orogen. The crustal structure of the orogen is, therefore, not mirrored in the mantellic root.

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The origin of reaction textures in mantle peridotite xenoliths from Sal Island, Cape Verde: the case for “metasomatism” by the host lava

Cited by 87 publications

References 27 publications

Melt variability in percolated peridotite: an experimental study applied to reactive migration of tholeiitic basalt in the upper mantle

Melt variability in percolated peridotite: an experimental study applied to reactive migration of tholeiitic basalt in the upper mantle

Understanding the textures and origin of shock melt pockets in Martian meteorites from petrographic studies, comparisons with terrestrial mantle xenoliths, and experimental studies

Lithospheric mantle beneath NE part of Bohemian Massif and its relation to overlying crust: new insights from Pilchowice xenolith suite, Sudetes, SW Poland

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