calcite bearing dolomite carbonatite dykes from veseloe

Using spectral mixture analysis of hyperspectral remote ...

The reflectance spectra of dolomite car- ... Nd3+ characteristic of rare-earth element-bearing minerals (e.g. Rowan et al. 1986). ... and carbonatite dykes, distinguished by image analysis as a mixture of fenite and carbonatite (yellow in the colour com-posite). Other parts of .

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Mineralium Deposita.hu

rim of phlogopite-diopside clinopyroxenite surrounding a plug of calcite carbonatite and dolomite carbonatite dykes and veins that contain variable proportions of apatite- phlogopite-magnetite ± pyrochlore ± metasomatic Na-Ca amphiboles ± zircon.

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REE Daughter Minerals Trapped in Fluid Inclusions in the ...

The Bayan Obo REE-Nb-Fe deposit hosts the world''s largest known REE resource. The deposit consists of replacement bodies hosted in dolomite marble and of magnetite, REE fluorocarbonates, fluorite aegirine, amphibole, calcite, and barite. Three types of fluid inclusions have been recognized: two-phase aqueous liquid-vapor (L-V), two- to three-phase CO2 (C), and three-phase liquid-vapor .

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Noble gas isotopes in minerals from phoscorites and ...

network of dykes and veins of greatly varying thickness (from first centimeters up to 100-120 meters and even more) cutting through clinopyroxenites and ijolites. The earliest calciocarbonatites and calcite-bearing phoscorites dominate at the current erosion level of the complex, and form stocks up to 160_300 m and a network of concentric dykes

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Petrography and mineral chemistry of carbonatites and mica ...

Dolomite and calcite correspond to the chief constituents, but other carbonate phases, including the Ce-group RE minerals, are also recognized. Phosphates and oxides are widespread accessories whereas silicate minerals consist of olivine, clinopyroxene, mica and amphibole.

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U-Pb-zircon-ages-from-a-Devonian-carbonatite-dyke,-Kola ...

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Low mantle plume component in 370 Ma old Kola ultrabasic ...

During Devonian pulse of alkaline magmatism (370 Ma ago) 18 ultrabasic-alkaline-carbonatite complexes were formed on the Kola Peninsula. Rare gas isotope abundances were studied in ~300 samples from 8 complexes and also from Devonian dikes. A comparison of expected from in-situ closed-system production (calc) and measured (meas) abundances has shown that 4He meas .

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Oka Carbonatite - ALEX STREKEISEN

1) Carbonatites are a diverse group, but most of the carbonatite in the Oka complex are coarse-grained calcite-carbonatite (sovite) with accessory amounts of sodian augite, biotite, apatite, nepheline, monticellite, melilite, pyrochlore, perovskite, niocalite (Oka is .

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Rare Earth Mineralization in Igneous Rocks - Elements ...

In the early 1990s, 30–35% of the total production of ca 50,000 tonnes of total rare earth oxides (REOs) came from the carbonatite-hosted Mountain Pass deposit in California, USA, 5–10% from Chinese carbonatites, and 10–15% from loparite mines in nepheline syenites at Lovozero, Russia.

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fenite – mineralcollectionblog

Dec 15, 2016· Open pit in Khlebodarivka (Chlebodarovka) village exposes enderbite (charnockitic tonalite), cut by veins and dykes of camptonite (lampropyre), carrying megacrysts of biotite, amphibole, augite, anorthoclase, as well as veins (dykes) of calcite-carbonatite with exocontact fenitic aureole.

dolomite production 797

Calcium Magnesium Carbonate CaMg(CO 3)2 In England, dolomite has become a useful source for the production of magnesite by reacting calcined dolomite ... Calcite-bearing dolomite carbonatite dykes from . Calcite-bearing dolomite carbonatite dykes from Veseloe, North Transbaikalia, Russia and possible Cr-rich mantle xenoliths

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The mineralogy, geochemistry and geochronology of the ...

The purpose of this study was to explore the geology, mineralogy, geochemistry, and geochronology of the Wicheeda Carbonatite Complex. The complex consists of a carbonatite plug with a number of carbonatite and potassic-syenite dykes and sills emplaced into the sedimentary rocks of the upper Cambrian and lower Ordovician Kechika Group.

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Genesis of ultramafic lamprophyres and carbonatites at ...

Numerous dykes of ultramafic lamprophyre (aillikite, mela-aillikite, damtjernite) and subordinate dolomite-bearing carbonatite with U-Pb perovskite emplacement ages of ∼590-555 Ma occur in the vicinity of Aillik Bay, coastal Labrador.

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1986 DIAMOND DRILLING - British Columbia

from which the carbonatite magma was derived. Attempts to age-date these alkaline fragments are currently underway at IJBC. The amphibole is cut by numerous veins and dykes up to 50 m wide of dolomite and calcite carbonatite. The Fenite Halo is made up .

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Отпечаток факса на всю страницу

dolomite and calcite-dolomite carbonatites have also been recognised (Tao et al., 1998). Other mineral constituents typically include apatite, magnetite, quartz, amphibole, K- feldspar and biotite. Secondary monazite minerahsation occurs in some dykes (Le Bas et al., 1992). The dykes are surrounded by fenite haloes, composed of aegirine, sodic

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Deposit Portal - Mount Weld

Carbonatite dykes persist for up to 5 km from the main body. The carbonatite is dominantly calcitic (sövite with beforsite) and dolomitic (rauhaugite) igneous rock types that contain more than 50% carbonate, while biotite and apatite may locally predominate.

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Abundance of REE-bearing minerals in carbonatite and ...

The studied samples represent carbonatite and lamprophyre dikes of the Fenite zone. The miner-alogy of the samples was examined by using XRD, MLA, EMPA, SEM and light microscope. X-ray diffraction analysis show that weathered materials are mainly composed of quartz, feldspar, carbonates (calcite and dolomite), clay minerals

Reexamination of the Genesis of the Bayan Obo Fe-REE-Nb ...

numerous carbonatitic dykes in the region of the deposits, which helped LeBas et al. (1992) to hypothesize a ... As the carbonatite melt becomes depleted in ferrous iron with oxidation, calcite and (or) dolomite begin to crystallize with magnetite. Regardless, if this .

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Genesis of the Bayan Obo Feâ - LA-ICPMS laboratory in ...

(a) Dolomite grains from coarse-grained dolomite; (b) dolomite grains from fine-grained dolomite; (c) dolomite grains from dolomite carbonatite; (d) calcite grains from calcite carbonatite. 5.2.1. Evidence from depositional age of H8 The timing of mineralization in Bayan Obo has .

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THE FEN CARBONATITE COMPLEX, ULEFOSS, SOUTH .

o The best grades were observed in hematite-rich carbonatite (rodbergite) and iron (hematite)-ore o Metallurgical recoveries were low due to very fine grain-size of RE oxides (1µ). The grains size of RE oxides in calcite- (50-70% >43µ) and ankerite-dolomite carbonatite is .

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Phoscorite-Carbonatite Pipe Complexes

PCP complexes calcite-carbonatite is the dominant rock type, followed by dolomite-carbonatite. Carbonatites occur in close spatial and tempo-ral association with phoscorites and often form multiphase phoscorite-carbonatite series. The phoscorite-carbonatite series are mantle-derived rocks, and much discussion centres on whether

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Geological and Geochemical Characteristics and Genesis of ...

Bayan Obo "dolomite" is distributed mainly at the south wing of the Kuangou anticline in the northern margin of the North China Craton.It is not only host to world''s largest rare earth deposit but also parental rock for the large or very large niobium,iron,scandium and other minerals.The "dolomite" is not layered rock due to lacking no obvious bedding and fixed sequence,but a beded dolomite ...

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dolomite rare earth ore tanzanian

dolomite rare earth ore tanzanian dolomite rare earth ore tanzanian Rare earth element minerals in four carbonatites near Gatineau. development of rare earth element (REE) minerals in car bonatites of a specificand calcite,dolomite and barite or calcite and barite frac tions.Some are elsewhere,such as those at Wigu Hill,Tanzania (Heinrich.1966) and near the.

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Carbonatite | Magma | Minerals

The name was first introduced by Brogger (1921) in describing the calcite rich igneous rocks within the Fen Alkaline Complex of Norway. The term ''carbonatite '' refers to the abundance of magmatic carbonate minerals coexisting with the silicate minerals. Carbonatite resembles limestone or coarse marble in the outcrop and hand specimen.

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ABSTRACTS & EXCURSION GUIDES 18th to 22nd .

carbonatite dyke penetrating carbonatized trachyte and trachytic breccia has two macroscopically distinct facies: (i) a brecciated upper section, and (ii) a macro- ... of mixtures of calcite and Fe-bearing dolomite. The small domains (~20 μm) of dolomite are randomly distributed throughout the prevailing calcite. The shape

ABSTRACTS & EXCURSION GUIDES 18th to 22nd .

carbonatite dyke penetrating carbonatized trachyte and trachytic breccia has two macroscopically distinct facies: (i) a brecciated upper section, and (ii) a macro- ... of mixtures of calcite and Fe-bearing dolomite. The small domains (~20 μm) of dolomite are randomly distributed throughout the prevailing calcite. The shape

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Mineral Potential of Malawi 1 - British Geological Survey

entire ring complex is cut by dykes and veins of pegmatite, microsyenite and lamprophyre. Nepheline is unknown and there is no association with carbonatite. Deformed alkaline rocks and carbonatites may mark Proterozoic suture zones where oceans have opened and closed. This Neoproterozoic Rift belt has remained a zone

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mining associated with carbonatite

In addition to the carbonatite formerly mined for Nb, there is an REE-rich ... to 1760 when Pope Clemente XIII received a metallic medallion from this "gold mine". ... deposits associated with alkaline-carbonatite volcano-plutonic complexes.

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Cr-bearing mineral phases in Genesis of titanomagnetite ...

New location of carbonatites (Veseloe) was revealed in limits of carbonatite-bearing area of Northern Transbaikalia in 2003. It is located in a frame of Early Precambrian crystal base and is represented by beforsite dykes. Comagmatic alkaline silicate rocks were not found in the nearest environment.

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Oka Carbonatite - ALEX STREKEISEN

Alex Strekeisen - I vetrini della mia fantasia. Oka Carbonatite The Oka complex is part of the Monteregian petrographic province, a group of igneous intrusions lying along an arc extending for about 140 miles from Oka through Montreal to the Western Appalachians.

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Carbonatite-lava extrusions along ring-fractures south of ...

) during pre-eruptive state. Calcite is the essential mineral. The rock is Fe and Ti poor, Mg is relatively enriched over FeO but maximum dolomite content reaches only up to 29%. Barite, witherite, alkali carbonates and salts of alkali aluminates are present in this .

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The Petrogenetic Association of Carbonatite and Alkaline ...

The Petrogenetic Association of Carbonatite and Alkaline Magmatism: Constraints from the Spitskop Complex, South Africa. Journal of Petrology, Apr 1999

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Original paper Carbonate-rich dyke in Roztoky Intrusive ...

dolomite occurs in the alkaline dyke from the Ralsko Hill, NE Bohemia (Ulrych et al. 1997). Primary carbonate in a metasomatized harzburgite xenolith was described by Frýda and Vokurka (1995) from the České Středohoří Volcanic Complex. Here, we report on the presence of a silicocarbonatite dyke in the Roztoky Intrusive Complex, the axial and

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