scholarly journals Partitioning of REE between calcite and carbonatitic melt containing P, S, Si at 900-650 °C and 100 MPa

2021 ◽  
Author(s):  
Dmitry A. Chebotarev ◽  
Cora Wohlgemuth-Ueberwasser
Keyword(s):  
Fractional Crystallization ◽  
Distribution Coefficients ◽  
Pressure Vessels ◽  
Significant Control ◽  
Icp Ms ◽  
Present Information ◽  
Magmatic Stage ◽  
Ree Fractionation ◽  
Powerful Mechanism ◽  
Carbonatite Magma

Abstract Many carbonatites host deposits of REE and HFSE, and fractional crystallization might be a potentially powerful mechanism controlling magma enrichment by these metals to economically significant values. At present, information about the control of fractional crystallization by partition coefficients of ore-forming elements at magmatic stage is incomplete. Here we present an experimental study of REE partitioning between carbonatite melt and calcite in the system CaCO3-Na2CO3 with varying amounts of P2O5, F, Cl, SiO2, SO3 at 650–900°C and 100 MPa using cold-seal pressure vessels and LA-ICP-MS. The presence of phosphorus in the system generally increases the distribution coefficients but its effect decreases with increasing concentration. The influence of temperature is great: at 900 − 770°C DREE ≥1, while at lower temperatures the values are below unity. Silicon also promotes the fractionation of REE into calcite, while sulfur contributes to the retention of REE in the melt. Our results imply that calcite may impose significant control upon REE fractionation at the early stages of crystallization of carbonatite magma and can be a closest proxy for monitoring the REE content in initial melt.

scholarly journals Origin of alkali-rich volcanic and alkali-poor intrusive carbonatites from a common parental magma

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Ivan F. Chayka ◽  
Vadim S. Kamenetsky ◽  
Nikolay V. Vladykin ◽  
Alkiviadis Kontonikas-Charos ◽  
Ilya R. Prokopyev ◽  
...  
Keyword(s):  
Empirical Evidence ◽  
Fractional Crystallization ◽  
Melt Inclusions ◽  
Parental Magma ◽  
Progressive Increase ◽  
Topical Problem ◽  
Oldoinyo Lengai ◽  
Southern Siberia ◽  
Magmatic Stage ◽  
Common Parent

AbstractThe discrepancy between Na-rich compositions of modern carbonatitic lavas (Oldoinyo Lengai volcano) and alkali-poor ancient carbonatites remains a topical problem in petrology. Although both are supposedly considered to originate via fractional crystallization of a “common parent” alkali-bearing Ca-carbonatitic magma, there is a significant compositional gap between the Oldoinyo Lengai carbonatites and all other natural compositions reported (including melt inclusions in carbonatitic minerals). In an attempt to resolve this, we investigate the petrogenesis of Ca-carbonatites from two occurrences (Guli, Northern Siberia and Tagna, Southern Siberia), focusing on mineral textures and alkali-rich multiphase primary inclusions hosted within apatite and magnetite. Apatite-hosted inclusions are interpreted as trapped melts at an early magmatic stage, whereas inclusions in magnetite represent proxies for the intercumulus environment. Melts obtained by heating and quenching the inclusions, show a progressive increase in alkali concentrations transitioning from moderately alkaline Ca-carbonatites through to the “calcite CaCO3 + melt = nyerereite (Na,K)2Ca2(CO3)3” peritectic, and finally towards Oldoinyo Lengai lava compositions. These results give novel empirical evidence supporting the view that Na-carbonatitic melts, similar to those of the Oldoinyo Lengai, may form via fractionation of a moderately alkaline Ca-carbonatitic melt, and therefore provide the “missing piece” in the puzzle of the Na-carbonatite’s origin. In addition, we conclude that the compositions of the Guli and Tagna carbonatites had alkali-rich primary magmatic compositions, but were subsequently altered by replacement of alkaline assemblages by calcite and dolomite.

scholarly journals Gold Partitioning in a Model Multiphase Mineral-Hydrothermal Fluid System: Distribution Coefficients, Speciation and Segregation

Minerals ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 890 ◽  
Author(s):  
Sergey Lipko ◽  
Vladimir Tauson ◽  
Valeriy Bychinskii
Keyword(s):  
Inductively Coupled Plasma ◽  
Fluid Phase ◽  
Distribution Coefficients ◽  
Crystal Defects ◽  
Geothermal Systems ◽  
Fluid System ◽  
Experimental Conditions ◽  
Inductively Coupled ◽  
Ms Analysis ◽  
Icp Ms

The characteristics of Au partitioning in a multiphase, multicomponent hydrothermal system at 450 °C and 1 kbar pressure were obtained using experimental and computational physicochemical modelling and laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) analysis. Sphalerite and magnetite contained 0.1–0.16 ± 0.02 µg/g Au and coexisted with galena and bornite which contained up to 73 ± 5 and 42 ± 10 µg/g Au, respectively. Bornite and chalcopyrite were the most effective Au scavengers with cocrystallization coefficients Au/Fe and Au/Cu in mineral-fluid system n–n × 10−2. Sphalerite and magnetite were the weakest Au absorbers, although Fe impurity in sphalerite facilitated Au uptake. Using the phase composition correlation principle, Au solubility in minerals was estimated (µg/g Au): low-Fe sphalerite = 0.7, high-Fe sphalerite = 5, magnetite = 1, pyrite = 3, pyrite-Mn = 7, pyrite-Cu = 10, pyrrhotite = 21, chalcopyrite = 110, bornite = 140 and galena = 240. The sequence reflected increasing metallicity of chemical bonds. Gold segregation occurred at crystal defects, and on surfaces, and influenced Au distribution due to its segregation at crystal interblock boundaries enriched in Cu-containing submicron phases. The LA-ICP-MS analysis of bulk and surficial gold admixtures revealed elevated Au content in surficial crystal layers, especially for bornite and galena, indicating the presence of a superficial nonautonomous phase (NAP) and dualism in the distribution of gold. Thermodynamic calculations showed that changes in experimental conditions, primarily in sulfur regime, increased the content of the main gold species (AuCl2− and AuHS0) and decreased the content of FeCl20, the prevailing form of iron in the fluid phase. The elevation of S2 and H2S fugacity affected Au partitioning and cocrystallization coefficients. Using Au content in pyrite, chalcopyrite, magnetite and bornite from volcanic-sedimentary, skarn-hosted and magmatic-hydrothermal sulfide deposits, the ranges of metal ratios in fluids were estimated: Au/Fe = n × 10−4−n × 10−7 and Au/Cu = n × 10−4−n × 10−6. Pyrite and magnetite were crystallized from solutions enriched in Au compared to chalcopyrite and bornite. The presence of NAP, and associated dualism in distribution coefficients, strongly influenced Au partitioning, but this effect does not fully explain the high gold fractionation into mineral precipitates in low-temperature geothermal systems.

Pétrologie du granite peralcalin du lac Brisson, Labrador central, Nouveau-Québec. 1. Mode de mise en place et évolution chimique

1992 ◽  
Vol 29 (2) ◽  
pp. 353-372 ◽  
Author(s):  
D. Pillet ◽  
M. Chenevoy ◽  
M. Bélanger
Keyword(s):  
Fractional Crystallization ◽  
Fluid Phase ◽  
Major Elements ◽  
Magmatic Stage ◽  
Recent Phase ◽  
Element Enrichment ◽  
Magmatic Suite ◽  
End Members ◽  
Trace Element Enrichment ◽  
Middle Proterozoic

The Lake Brisson peralkaline granite in Labrador, which by way of its age of 1189 Ma is the most recent phase of the Gardar magmatic stage, was intruded in the Middle Proterozoic at the margin of a granulitic complex, retrograded to an amphibolite facies during Aphebian, and of an Elsonian adamellite pluton. It shows a petrographie zonation ("feldspathic" facies at the center, "quartzose" facies including early quartz at the edge) suggestive of a permissive multiphase intrusion, and is characterized by deuteritic alteration via metalliferous fluids (Zr, Y, Nb, Be; rare earths). All facies are Na-peralkaline, well evolved, and represent end-members of a differentiated magmatic suite of the designated A type. The relative behavior of the major elements indicates that the facies differentiation was controlled by fractional crystallization and was also greatly influenced by alkaline feldspath and by increase of f(O2) in the final stage of evolution. The trace elements contents, significantly higher than those reported for other peralkaline complexes, are a confirmation of the influence of fractional crystallization. The unsual trace element enrichment in an altered quartzose facies is the result of the effects of a final oxidizing fluid phase, rich in F; the relative depletion of Na and the enrichment in Sr and Ca of the fluid are explained by its having been contaminated by the wall rocks. [Journal Translation]

scholarly journals Critical Metals Ga, Ge and In: Experimental Evidence for Smelter Recovery Improvements

Minerals ◽  
2019 ◽  
Vol 9 (6) ◽  
pp. 367 ◽  
Author(s):  
Katri Avarmaa ◽  
Lassi Klemettinen ◽  
Hugh O’Brien ◽  
Pekka Taskinen ◽  
Ari Jokilaakso
Keyword(s):  
Distribution Coefficient ◽  
Copper Slag ◽  
Distribution Coefficients ◽  
Copper Smelting ◽  
High Tech ◽  
Process Conditions ◽  
Critical Metals ◽  
Analytical Technique ◽  
Icp Ms ◽  
Secondary Copper Smelting

High-tech metals, including Ga, Ge and In, are critical for the performance of electrical and electronic equipment (EEE). None of these three metals exist in mineable levels in natural minerals, and thus their availability and production are dependent on the primary and secondary base metals (including Zn, Al and Cu) production. To secure the supply of high-tech metals in the future, their behavior, including distribution coefficients (LCu/s = [wt% M]in copper/(wt% M)in slag), in primary and secondary processes need to be characterized. This study reports three series of copper-slag distribution experiments for Ga, Ge and In in simulated secondary copper smelting and refining process conditions (T = 1300 °C, pO2 = 10−9–10−5 atm) using a well-developed drop–quench technique followed by EPMA and LA-ICP-MS analyses. This study shows how an analytical technique more traditionally applied to the characterization of ores or minerals can also be applied to metallurgical process investigation. The LA-ICP-MS analysis was used for the first time for measuring the concentrations of these minor elements in metallurgical glasses, i.e., slags, and the results were compared to the geological literature. The distribution coefficient of indium increased as a function of decreasing oxygen partial pressure from 0.03 to 10, whereas the distribution coefficient of gallium was 0.1 at 10−9 atm and decreased as the pO2 increased. The concentrations of gallium in slags were between 0.4 and 0.6 wt% and germanium around 1 ppm. Germanium was vaporized almost entirely from the samples.

Development of the Early Continental Crust. Part 1. Use of Trace Element Distribution Coefficient Models for the Protoarchean Crust

1972 ◽  
Vol 9 (12) ◽  
pp. 1577-1595 ◽  
Author(s):  
Denis M. Shaw
Keyword(s):  
Distribution Coefficient ◽  
Trace Element ◽  
Continental Crust ◽  
Fractional Crystallization ◽  
Distribution Coefficients ◽  
Element Distribution ◽  
Trace Element Distribution ◽  
Measured Distribution

The original continental crust developed as the residue from fractional crystallization of the mantle–crust system. Using measured distribution coefficients for K, Rb, Ba, Sr, La, Ce, Eu, Yb, and Ni, several crystallization models are tested for conformity with regional geochemical estimates of continental crustal composition.In spite of the uncertainties and approximations the predicted concentrations agree reasonably well with observation, except in the case of Yb.

scholarly journals Vendian and Permian-Triassic plagiogranite magmatism of the Ust’-Belaya Mountains, West-Koryak fold system, Northeastern of Russia

2019 ◽  
pp. 87-114
Author(s):  
A. V. Moiseev ◽  
M. V. Luchitskaya ◽  
I. V. Gul’pa ◽  
V. B. Khubanov ◽  
B. V. Belyatsky
Keyword(s):  
Rare Earth ◽  
Partial Melting ◽  
Rare Earth Element ◽  
Fractional Crystallization ◽  
Earth Element ◽  
Island Arc ◽  
Active Margin ◽  
Fold System ◽  
Icp Ms ◽  
Low K

Vendian and Permian-Triassic plagiogranite magmatism is distinguished for Ust’-Belsky and Algansky terranes of West-Koryak fold system. U–Pb zircon ages from Vendian and Permian-Triassic plagiogranites are 556 ± 3 Ma (SIMS), 538 ± 7 Ma (LA–ICP–MS) and 235 ± 2 Ma (SIMS) consequently. It is revealed, that Vendian and Permian-Triassic plagiogranites are mainly low-K and low-Al. Sr–Nd isotopy and rare-earth element patterns allow supposing their formation by partial melting of primarily mantle substrate or by fractional crystallization of basic magma. Vendian plagiogranites formed within active margin in ensimatic island arc simultaneously with deposition of lower part of volcanic-sedimentary complex of Otrozhninskaya slice. We suggest the Permian-Triassic plagiogranites were being formed within the limits of Ust’-Belsky segment of Koni-Taigonos arc during partial melting of melanocratic ophiolite material build up as fragments in accretionary structure of that arc or by fractional crystallization of basic magmas melted from the similar substrate.

scholarly journals Bands of Zircon, Allanite and Magnetite in Paleozoic Alkali Granite in the Chungju Unit, South Korea, and Origin of REE Mineralizations

Minerals ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 566 ◽  
Author(s):  
Sang-Gun No ◽  
Maeng-Eon Park
Keyword(s):  
South Korea ◽  
Fractional Crystallization ◽  
Inductively Coupled Plasma ◽  
Alkali Granite ◽  
Alkaline Granite ◽  
Inductively Coupled ◽  
Ree Mineralization ◽  
Geological Unit ◽  
Icp Ms ◽  
Plasma Mass Spectrometry

High-grade Zr–Nb–Y–rare earth element (REE) mineralization occurs as zircon–allanite–magnetite bands in layered Paleozoic alkali rocks which intruded the Gyemyeongsan Formation of the Chungju unit, South Korea. The mineralization period and genesis have been controversial. We investigated the petrological and mineralogical properties of the newly discovered zircon–allanite–magnetite bands and the geochronological properties of zircon within the bands in the alkali granite. We analyzed the zircon with laser ablation multi-collector inductively coupled plasma mass spectrometry (LA-MC-ICP-MS). The repeated quartz–feldspar-rich layers in the alkali granite show grain-sized grading textures and equilibrium igneous textures. Magnetite and allanite grains in these layers varied in size and exhibited isolated, aggregated, and coalesced textures. In addition, the settling texture of zircon grains onto the other minerals was observed. These observations could reasonably be explained by the process of gravitational accumulation during the solidification of magma. The 206Pb/238U ages obtained from zircon from the zircon–allanite–magnetite-rich layer and the alkali aplite were 331.1 ± 1.5 Ma and 334.5 ± 8.9 Ma, respectively. Therefore, we suggest that the Zr–Y–Nb–REE mineralization developed in the alkali rocks and the Gyemyeongsan Formation in the Chungju unit were formed by fractional crystallization of alkali magma and hydrothermal fluids which evolved from alkali magma fractional crystallization, respectively. The correlation between alkaline granite and REE mineralization found in this study could be used as a tool for REE exploration in other regions where the permeable geological unit is intruded by the alkali granite.

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