Influence of water and fluorine on melting of carbonated peridotite at 6 and 10 GPa

Brey, Gerhard P.; Bulatov, Vasily V.; Гирнис, А. В.

doi:10.1016/j.lithos.2009.04.037

Cited by 88 publications

(36 citation statements)

References 62 publications

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“…11). Even if compared with recent studies on wet carbonated peridotites with high potassium and volatiles content (Brey et al 2009;Foley et al 2009) which reaches its maximum near 8 GPa (Fig. 6a).…”

Section: Melting Systematics For Carbonated Lithologiesmentioning

confidence: 58%

“…The generation of first highly potassic carbonatite melt at 8 GPa is controlled by a melting out of carbonates and K-phases. The melting reaction is similar for all three bulk (Yaxley and Brey 2004;Dasgupta et al 2004Dasgupta et al , 2005, peridotites (Brey et al 2008(Brey et al , 2009Ghosh et al 2009), and sediments (Thomsen and Schmidt 2008b). Note the correlation between carbonate and bulk composition, in particular of the Mg# of magnesite and the bulk.…”

Section: Melting Reactionsmentioning

confidence: 77%

“…The solidus for carbonated, wet and K 2 O-rich peridotites lies at temperatures between 1,100 and 1,200°C at oxidizing conditions from 8 to 13 GPa (Ghosh et al 2009;Brey et al 2009;Foley et al 2009) which is about 200°C below the average mantle geotherm (Akaogi et al 1989; Fig. 11).…”

Section: Evidence For Subducted Carbonates and K-rich Metasomatism Inmentioning

confidence: 99%

“…With respect to the dry solidus (DG2) of carbonated pelite, melting is only feasible for extremely hot subduction (Kincaid and Sacks 1997;van Keken et al 2002;Peacock 2003) and the mantle geotherm (Akaogi et al 1989) yields melting of these pelites only feasible during very hot subduction or at the end of convergence when subduction halts and thermal relaxation towards the mantle adiabat may occur. (1) is the solidus of potassium-rich hydrous carbonated peridotite compiled from Ghosh et al (2009), Foley et al (2009) and Brey et al (2009. Note that the curve GS09 of Ghosh et al (2009) denotes the carbonate-out of a K-bearing peridotite, but that Ghosh et al (2009) argue for a solidus at ca.…”

Section: Melting Systematics For Carbonated Lithologiesmentioning

confidence: 99%

“…Later melting of these metasomatic enriched mantle veins (Foley 1992) and domains will produce alkali-rich carbonatites with high concentrations of incompatible elements and a hybrid mantle/crust geochemical characteristics. These carbonatites may then evolve to the different highly alkaline ultrapotassic silicate melts that form group II kimberlites, lamproites and aillikites (Foley et al 2009;Brey et al 2009;Francis and Patterson 2009). Geochemical data of many alkali rocks, associated carbonatites, and of kimberlites and related rocks show isotopical characteristics on the mixing line between the HIMU (recycled altered oceanic crust) and EM1 (subducted oceanic crust and pelagic sediments) mantle endmembers (Faure 2000;Becker and Le Roex 2006).…”

Section: Evidence For Subducted Carbonates and K-rich Metasomatism Inmentioning

confidence: 99%

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Melting of carbonated pelites at 8–13 GPa: generating K-rich carbonatites for mantle metasomatism

Grassi

Schmidt

2010

Contrib Mineral Petrol

104

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The melting behaviour of three carbonated pelites containing 0-1 wt% water was studied at 8 and 13 GPa, 900-1,850°C to define conditions of melting, melt compositions and melting reactions. At 8 GPa, the fluidabsent and dry carbonated pelite solidi locate at 950 and 1,075°C, respectively; [100°C lower than in carbonated basalts and 150-300°C lower than the mantle adiabat. From 8 to 13 GPa, the fluid-present and dry solidi temperatures then increase to 1,150 and 1,325°C for the 1.1 wt% H 2 O and the dry composition, respectively. The melting behaviour in the 1.1 wt% H 2 O composition changes from fluid-absent at 8 GPa to fluid-present at 13 GPa with the pressure breakdown of phengite and the absence of other hydrous minerals. Melting reactions are controlled by carbonates, and the potassium and hydrous phases present in the subsolidus. The first melts, which composition has been determined by reverse sandwich experiments, are potassium-rich Ca-FeMg-carbonatites, with extreme K 2 O/Na 2 O wt ratios of up to 42 at 8 GPa. Na is compatible in clinopyroxene with D cpx=carbonatite Na ¼ 10À18 at the solidus at 8 GPa. The melt K 2 O/Na 2 O slightly decreases with increasing temperature and degree of melting but strongly decreases from 8 to 13 GPa when K-hollandite extends its stability field to 200°C above the solidus. The compositional array of the sediment-derived carbonatites is congruent with alkali-and CO 2 -rich melt or fluid inclusions found in diamonds. The fluid-absent melting of carbonated pelites at 8 GPa contrasts that at B5 GPa where silicate melts form at lower temperatures than carbonatites. Comparison of our melting temperatures with typical subduction and mantle geotherms shows that melting of carbonated pelites to 400-km depth is only feasible for extremely hot subduction. Nevertheless, melting may occur when subduction slows down or stops and thermal relaxation sets in. Our experiments show that CO 2 -metasomatism originating from subducted crust is intimately linked with K-metasomatism at depth of [200 km. As long as the mantle remains adiabatic, lowviscosity carbonatites will rise into the mantle and percolate upwards. In cold subcontinental lithospheric mantle keels, the potassic Ca-Fe-Mg-carbonatites may freeze when reacting with the surrounding mantle leading to potassium-, carbonate/diamond-and incompatible element enriched metasomatized zones, which are most likely at the origin of ultrapotassic magmas such as group II kimberlites.

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Section: Melting Systematics For Carbonated Lithologiesmentioning

confidence: 58%

Section: Melting Reactionsmentioning

confidence: 77%

Section: Evidence For Subducted Carbonates and K-rich Metasomatism Inmentioning

confidence: 99%

Section: Melting Systematics For Carbonated Lithologiesmentioning

confidence: 99%

Section: Evidence For Subducted Carbonates and K-rich Metasomatism Inmentioning

confidence: 99%

See 3 more Smart Citations

Melting of carbonated pelites at 8–13 GPa: generating K-rich carbonatites for mantle metasomatism

Grassi

Schmidt

2010

Contrib Mineral Petrol

104

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Anatomy of Intraplate Monogenetic Alkaline Basaltic Magmatism

Brenna

Ubide

Nichols

et al. 2021

Geophysical Monograph Series

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Intraplate basaltic systems, often occurring as fields of small monogenetic volcanoes, are dominated by eruption of alkaline basaltic rocks, ranging from nephelinite/basanite to transitional/subalkaline. Their generally primitive erupted compositions imply limited crustal modification, and hence they provide an important probe into deep, lithospheric mantle and partial melting processes. Partial melting and magmatic ascent processes can be investigated using the composition of crystals, glass and wholerock, although a combination of these is preferable. The whole-rock chemical variability within single eruptions or over the temporal and spatial extent of a volcanic field is controlled by the characteristics of the primary melting source, as well as near source percolative/reaction processes. Coupled crystaland -whole-rock detailed investigations are most promising to constrain the processes that modify primary melts into the primitive magmas that accumulate before ascent. Complex crystal textures and chemistry have so far demonstrated that basaltic magmas are principally processed and modified within the lithospheric mantle with minor modification en-route through the crust. Fractional crystallization and magma mixing modify melts throughout ascent, and can imprint secondary chemical intra-eruptive variability. Quantifiable temperature and pressure parameters based on crystalmelt compositions constrain the depth of formation, and hence provide information about the role of different mineral phases in deep versus shallow chemical evolution. Volatile components in the melt (e.g. H2O and CO2) can be quantified on glass and melt inclusions. These analyses, coupled with solubility models, may help to reconstruct initial dissolved volatile content to further constrain the source characteristics and magmatic ascent dynamics. Integrated studies of crystals and melt paint a picture of extended lithospheric mantle to minor crustal processing resulting from the complex deep plumbing of monogenetic basaltic systems. This highlights the need for improved resolution to characterize true primary signatures and hence elucidate the formation of intraplate alkaline basalts.

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Petrological modeling of basaltic rocks from Venus: A case for the presence of silicic rocks

Shellnutt

2013

JGR Planets

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The presence of highly evolved igneous rocks on Venus is a controversial issue. The formations of highland terranes and pancake domes are the two principal tectonic and volcanic features which argue in favor of the presence of silicic igneous rocks; however, the lack of water on Venus casts doubt on whether or not granites and rhyolites can form. Data returned to Earth from the Venera 13 and 14 landers show that the surface of Venus is composed of basaltic rocks similar in composition to those found on Earth. Here it is shown that anhydrous and hydrous fractional crystallization modeling using the Venera 13 and 14 data as starting materials can produce compositions similar to terrestrial phonolites and rhyolites. It is suggested that at shallow crustal levels (i.e., ≤ 0.1 GPa), mafic magmas can differentiate into silicic magmas resembling phonolites or rhyolites which may or may not erupt. Furthermore, the hydrous equilibrium partial melting models can produce rocks similar to terrestrial andesites and rhyolites, whereas anhydrous models suggest that there may be a uniquely Venusian type of silicic rock. The silicic rocks, if present, could act as “continental nucleation” sites and/or their presence may facilitate preferential sites of shearing and deformation of the Venusian crust.

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Influence of water and fluorine on melting of carbonated peridotite at 6 and 10 GPa

Cited by 88 publications

References 62 publications

Melting of carbonated pelites at 8–13 GPa: generating K-rich carbonatites for mantle metasomatism

Melting of carbonated pelites at 8–13 GPa: generating K-rich carbonatites for mantle metasomatism

Anatomy of Intraplate Monogenetic Alkaline Basaltic Magmatism

Petrological modeling of basaltic rocks from Venus: A case for the presence of silicic rocks

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