Silicate melt inclusions from a mildly peralkaline granite in the Oslo paleorift, Norway

AbstractThe mildy peralkaline Eikeren-Skrim granite belongs to the Permian magmatic province of the Oslo rift, south-east Norway. Euhedral quartz crystals from the abundant miarolitic cavities contain primary inclusions of partly crytallized silicate melts and coexisting primary, aqueous fluid inclusions. Micro-thermometric measurements give maximum estimates for the granite solidus of 685–705°C. Quenched silicate melt inclusions are not peralkaline, have normative Or/Ab weight ratios of 1.15–1.44 (compared to 0.49–0.80 in whole-rock samples) and F and Cl contents of 0.1 and 0.21–0.65 wt. %, respectively. Coexisting magmatic fluid inclusions are highly enriched in Na, Cl, S and to some extent K. These chemical characteristics are the results of late-magmatic melt-mineral-fluid interaction in the miarolitic cavities.

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Coexisting silicate melt inclusions and H2O-bearing, CO2-rich fluid inclusions in mantle peridotite xenoliths from the Carpathian–Pannonian region (central Hungary)

Chemical Geology ◽

10.1016/j.chemgeo.2010.03.004 ◽

2010 ◽

Vol 274 (1-2) ◽

pp. 1-18 ◽

Cited By ~ 29

Author(s):

Károly Hidas ◽

Tibor Guzmics ◽

Csaba Szabó ◽

István Kovács ◽

Robert J. Bodnar ◽

...

Keyword(s):

Fluid Inclusions ◽

Melt Inclusions ◽

Mantle Peridotite ◽

Silicate Melt ◽

Peridotite Xenoliths

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Exsolved magmatic fluid and its role in the formation of comb-layered quartz at the Cretaceous Logtung W-Mo deposit, Yukon Territory, Canada

Earth and Environmental Science Transactions of the Royal Society of Edinburgh ◽

10.1017/s0263593300006696 ◽

1996 ◽

Vol 87 (1-2) ◽

pp. 291-303 ◽

Cited By ~ 29

Author(s):

Jacob B. Lowenstern ◽

W. David Sinclair

Keyword(s):

Volcanic Rocks ◽

Hydrothermal Solution ◽

Aqueous Fluid ◽

Yukon Territory ◽

Magmatic Fluid ◽

Type I ◽

Type Ii ◽

Quartz Crystals ◽

High Silica ◽

Solidification Texture

ABSTRACT:Comb-layered quartz is a type of unidirectional solidification texture found at the roofs of shallow silicic intrusions that are often associated spatially with Mo and W mineralisation. The texture consists of multiple layers of euhedral, prismatic quartz crystals (Type I) that have grown on subplanar aplite substrates. The layers are separated by porphyritic aplite containing equant phenocrysts of quartz (Type II), which resemble quartz typical of volcanic rocks and porphyry intrusions. At Logtung, Type I quartz within comb layers is zoned with respect to a number of trace elements, including Al and K. Concentrations of these elements as well as Mn, Ti, Ge, Rb and H are anomalous and much higher than found in Type II quartz from Logtung or in igneous quartz reported elsewhere. The two populations appear to have formed under different conditions. The Type II quartz phenocrysts almost certainly grew from a high-silica melt between 600 and 800°C (as β-quartz); in contrast, the morphology of Type I quartz is consistent with precipitation from a hydrothermal solution, possibly as α-quartz grown below 600°C. The bulk compositions of comb-layered rocks, as well as the aplite interlayers, are consistent with the hypothesis that these textures did not precipitate solely from a crystallising silicate melt. Instead, Type I quartz may have grown from pockets of exsolved magmatic fluid located between the magma and its crystallised border. The Type II quartz represents pre-existing phenocrysts in the underlying magma; this magma was quenched to aplite during fracturing/degassing events. Renewed and repeated formation and disruption of the pockets of exsolved aqueous fluid accounts for the rhythmic banding of the rocks.

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Magmatic-Hydrothermal Evolution in the “Bottoms” of Porphyry Copper Systems: Evidence from Silicate Melt and Aqueous Fluid Inclusions in Granitoid Intrusions in the Gyeongsang Basin, South Korea

International Geology Review ◽

10.1080/00206819409465478 ◽

1994 ◽

Vol 36 (7) ◽

pp. 608-628 ◽

Cited By ~ 32

Author(s):

Kyounghee Yang ◽

Robert J. Bodnar

Keyword(s):

South Korea ◽

Fluid Inclusions ◽

Porphyry Copper ◽

Aqueous Fluid ◽

Silicate Melt ◽

Gyeongsang Basin ◽

Granitoid Intrusions

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Synthetic Fluid Inclusions XIV: Coexisting Silicate Melt and Aqueous Fluid Inclusions in the Haplogranite-H2O-NaCl-KCl System

Journal of Petrology ◽

10.1093/petroj/40.10.1509 ◽

1999 ◽

Vol 40 (10) ◽

pp. 1509-1525 ◽

Cited By ~ 43

Author(s):

J. J. Student ◽

R. J. Bodnar

Keyword(s):

Fluid Inclusions ◽

Aqueous Fluid ◽

Silicate Melt ◽

Synthetic Fluid Inclusions

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The potential for aqueous fluid-rock and silicate melt-rock interactions to re-equilibrate hydrogen in peridotite nominally anhydrous minerals

American Mineralogist ◽

10.2138/am-2021-7435 ◽

2020 ◽

Keyword(s):

Aqueous Fluid ◽

Silicate Melt ◽

Nominally Anhydrous Minerals

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Microthermometry and noble gas isotope analysis of magmatic fluid inclusions in the Kerman porphyry Cu deposits, Iran: constraints on the source of ore-forming fluids

Mineralium Deposita ◽

10.1007/s00126-021-01041-8 ◽

2021 ◽

Author(s):

Behnam Shafiei Bafti ◽

Samuel Niedermann ◽

Marta Sośnicka ◽

Sarah A. Gleeson

Keyword(s):

Fluid Inclusions ◽

Noble Gas ◽

Isotope Analysis ◽

Magmatic Fluid ◽

Porphyry Cu ◽

Noble Gas Isotope

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Lherzolite - carbonatite melt interaction in the presence of additive CO2 and H2O: Experimental data at 5.5 GPa and 1200-1450°C

10.5194/egusphere-egu21-9325 ◽

2021 ◽

Author(s):

Aleksei Kruk ◽

Alexander Sokol

Keyword(s):

Experimental Data ◽

Lithospheric Mantle ◽

Fluid Phase ◽

Experimental Results ◽

Silicate Melt ◽

Silicate Melts ◽

Garnet Lherzolite ◽

Russian Science ◽

Continental Lithospheric Mantle

We study the reaction of garnet lherzolite with carbonatitic melt rich in molecular CO2 and/or H2O in experiments at 5.5 GPa and 1200-1450&#176;C. The experimental results show that carbonation of olivine with formation of orthopyroxene and magnesite can buffer the CO2 contents in the melt, which impedes immediate separation of CO2 fluid from melt equilibrated with the peridotite source. The solubility of molecular CO2 in melt decreases from 20-25 wt.% at 4.5-6.8 wt.% SiO2 typical of carbonatite to 7-12 wt.% in more silicic kimberlite-like melts with 26-32 wt.% SiO2. Interaction of garnet lherzolite with carbonatitic melt (2:1) in the presence of 2-3 wt.% H2O and 9-13 wt.% molecular CO2 at 1200-1450&#176;&#1057; yields low SiO2 (<10 wt.%) alkali&#8208;carbonatite melts, which shows multiphase saturation with magnesite-bearing garnet harzburgite. Thus, carbonatitic melts rich in volatiles can originate in a harzburgite source at moderate temperatures common to continental lithospheric mantle (CLM).Having separated from the source, carbonatitic magma enriched in molecular CO2 and H2O can rapidly acquire a kimberlitic composition with >25 wt.% SiO2 by dissolution and carbonation of entrapped peridotite. Furthermore, interaction of garnet lherzolite with carbonatitic melt rich in K, CO2, and H2O at 1350&#176;&#1057; produces immiscible kimberlite-like carbonate-silicate and K-rich silicate melts. Quenched silicate melt develops lamelli of foam-like vesicular glass. Differentiation of immiscible melts early during ascent may equalize the compositions of kimberlite magmas generated in different CLM sources. The fluid phase can release explosively from ascending magma at lower pressures as a result of SiO2 increase which reduces the solubility of CO2 due to decarbonation reaction of magnesite and orthopyroxene.The research was performed by a grant of the Russian Science Foundation (19-77-10023).

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