Ta-Nb Mineralization in the Alkaline Rocks of the Eastern Azov Sea Area (Ukraine)

Kryvdik, S.G.; Sharygin, Victor V.; Dubyna, O.V.; Morgun, Vyacheslav; Tomurko, L.

doi:10.15407/mineraljournal.40.03.039

Cited by 5 publications

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“…In this study we focus on the Nb-and Ta-rich accessory phases pyrochlore, microlite, and fersmite, which are accessory phases in alkaline silicate rocks [14][15][16][17][18][19][20] and, perhaps more commonly, carbonatites [18,[21][22][23]. Note that these mineral phases are the most important hosts for Nb and Ta in ore deposits (e.g., [18,[24][25][26][27].…”

Section: Introductionmentioning

confidence: 99%

Trace element partitioning between pyrochlore, microlite, fersmite and silicate melts

Klemme

Berndt

2020

Geochem Trans

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We present experimentally determined trace element partition coefficients (D) between pyrochlore-group minerals (Ca 2 (Nb,Ta) 2 O 6 (O,F)), Ca fersmite (CaNb 2 O 6), and silicate melts. Our data indicate that pyrochlores and fersmite are able to strongly fractionate trace elements during the evolution of SiO 2-undersaturated magmas. Pyrochlore efficiently fractionates Zr and Hf from Nb and Ta, with D Zr and D Hf below or equal to unity, and D Nb and D Ta significantly above unity. We find that D Ta pyrochlore-group mineral/silicate melt is always higher than D Nb , which agrees with the HFSE partitioning of all other Ti-rich minerals such as perovskite, rutile, ilmenite or Fe-Ti spinel. Our experimental partition coefficients also show that, under oxidizing conditions, D Th is higher than corresponding D U and this implies that pyrochlore-group minerals may fractionate U and Th in silicate magmas. The rare earth element (REE) partition coefficients are around unity, only the light REE are compatible in pyrochlore-group minerals, which explains the high rare earth element concentrations in naturally occurring magmatic pyrochlores.

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Section: Introductionmentioning

confidence: 99%

Trace element partitioning between pyrochlore, microlite, fersmite and silicate melts

Klemme

Berndt

2020

Geochem Trans

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“…1). Із нашого розгляду ми виключили мінерали групи пі рохлору і колумбіту, результати дослідження яких опубліковані раніше (Kryvdik, Sharygin, Dubyna et. al., 2018;Sorohtina, Kryvdik, 2008).…”

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“…al., 2018;Sorohtina, Kryvdik, 2008). Інформація щодо деяких мінералів (польові шпати, оксиди типу гетиту та хлорити, які не (Kryvdik, Sharygin, Dubyna et al, 2018) включно. * Including data (Kryvdik, Sharygin, Dubyna et al, 2018).…”

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“…Можливо, важли вим компонентом флюїдної фази був і Cl, оскільки у згаданих вище дрібних фенітових прожилках постійним мінералом, у асоціації із лужними фемічними мінералами, бари том, аланітом та FREEкарбонатами, є хло раніт (до 9 % Cl) (Sharygin, Kryvdik, Kаr manov et al, 2014). За даними (Migdisov, Wil liamsJones, Wagner, 2009;WilliamsJones, Mig disov, Samson, 2012) (Haas, Shock, Sassani, 1995;Zaitsev, Keller, 2006) (Kryvdik, Sharygin, Dubyna et al, 2018;Sorohtina, Kryv dik, 2008) , zircon, and opaque (ilmenite, rutile, magnetite, sulfides). In addition to the abovementioned minerals, except for the minerals of pyrochlore group, chlorannite, aegyrine, REEcarbonates, baryte, allanite(Ce), REEapatite were found in the fenite haloes and veinlets.…”

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Mineralogy and Petrology of Carbonatites and Fenites from Khlibodarivka Occurrence

Dubyna,

Kryvdik,

Vyshnevskyi

2024

Mìneral. ž.

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The data of mineralogical studies of carbonatite veins and exocontact fenites in the open pit near the Khlibodarivka occurrence (Donetsk region, Volnovaha district) are presented. The thickness of carbonatite veins is neglegible, rarely exceeding 30 cm, and are mainly composed of calcite, alkaline amphibole and albite are the most common silicate minerals. Accessory minerals are more often represented by monazite, apatite, columbite, minerals of pyrochlore group, zircon, and opaque (ilmenite, rutile, magnetite, sulfides). In addition to the above-mentioned minerals, except for the minerals of pyrochlore group, chlorannite, aegyrine, REE-carbonates, baryte, allanite-(Ce), REE-apatite were found in the fenite haloes and veinlets. The reactionary interaction of the carbonatite melt enriched in alkalis and volatiles with the hosted enderbites caused the appearance of fenite halos both around the veins of carbonatites and the thin "net" of veinlets without a visible connection with carbonatites. The significant thickness of the fenite halos (usually twice as much in comparison to the thickness of the carbonatite veins), albitization of the surrounding rocks and saturation of the alkaline femic minerals of the carbonatite veins and fenites indicate that the initial carbonatite melt contained a significant amount of Na and volatile components (H2O, F, CO2, possibly Cl), and also had a more ferruginous composition of carbonates due to the presence of siderite or ankerite components (in the melt). As a result of the dissociation of primary carbonates, iron, as well as alkalis, was concentrated in the fluid phase and subsequently included in aegirine and alkaline amphiboles. The fenitization of host rocks took place in several stages. At the initial stage, the alkali-enriched fluids, mainly Na, F, and possibly Cl, were separated, while the later ones fluids were Fe-enriched and existing in more oxidized conditions. The fluids genetically related to carbonatites were penetrating into the host rocks caused the redistribution of trace elements. Barium, Th, and partly LREE were carried out from carbonatites most intensively, while Sr, Nb and a significant part of REE remained immobile due to the early crystallization of their host minerals and lack of subsequent autometasomatic alteration. Geochemistry of carbonatite veins (high content of incompatible elements such as Sr (11 7777 ppm), increased REE (1624 ppm), elevated Nb, chondrite-normalized pattern of REE, high (La/Yb)cn = 24.7 and absence of negative Eu anomaly (Eu* = 1.03) and endogenous ratios of isotopes of Sr (0.703), C and, partially, O) testify to their magmatic origin. It is possible that the insignificant thickness of the carbonatite veins and the intensive interaction of juvenile fluids with the host granitoids and meteoric fluids caused the enrichment of carbonatites with 18O (δ18O 8.4÷20), but with the preservation of primary δ13C (–8 ÷ –6.5). Currently, the increased concentrations of rare metals were not found in carbonatites of the Khlibodarivka village. However, the presence of carbonatite veins in association with fenite halo, spatial connection to the Oktyabrsky massif of alkaline rocks, as well as numerous fenite occurrences in this area, increase the prospects of this area for such mineralization.

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Geochemistry of Nb and Та in magmatic rocks of the Ukrainian Shield

Kryvdik¹,

Dubyna²

2020

Geohim. rudoutvorennâ

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It was made an attempt to generalize geochemical data of Nb and Ta concentration in the most common igneous rocks of the Ukrainian Shield (USh). In the majority of widely distributed rocks of the USh (normal and subalkaline granitoids) the Nb and Ta concentration are similar to upper crust but lower the accepted Clark value for acidic rocks. In the more differentiated rapakivi granites concentrations of these elements reach or exceed the Clark’s concentrations (up to 35 ppm). Only highly differentiated alkaline rocks and alkaline feldspar granites (Perga, Kamiani mogyly, Ruska Poliana massifs) have high Nb concentrations (up to 800, 120 and 370 ppm, respectively). Medium rocks of the normal range are the least geochemically studied and typically are characterized low Nb and Ta concentrations. Almost all gabbroids as well as their metamorphosed analogues in the greenstone structures, are characterized by very low Nb (and Ta) concentration (two or more orders of magnitude) compared with Clark’s values for basic rocks (20 ppm Nb and 0.48 ppm Ta) according to A.P. Vinogradov. Against this background, increased of Nb and Ta concentration is observed in the main rocks of anorthosite-rapakivi-granite plutons. Howover even in these rocks concentration of these elements rarely reach or does not achieve the values which are typical for subalkaline and alkaline basalts of continental rifts. The regional heterogeneity in Nb and Ta distribution is observed in alkaline rocks of different composition: in the Azov Sea region these rocks are characterized by high concentrations, while in the western part of the USh the content of these elements is extremely low. The increased concentration of these elements is also revealed in kimberlites from the Azov Sea region and the Kyrovohrad megablock of the USh. The authors give some considerations and assumptions about the dependence on geochemical features of the Precambrian igneous rocks of the USh from the geodynamic conditions of their formation.

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Ta-Nb Mineralization in the Alkaline Rocks of the Eastern Azov Sea Area (Ukraine)

Cited by 5 publications

References 3 publications

Trace element partitioning between pyrochlore, microlite, fersmite and silicate melts

Trace element partitioning between pyrochlore, microlite, fersmite and silicate melts

Mineralogy and Petrology of Carbonatites and Fenites from Khlibodarivka Occurrence

Geochemistry of Nb and Та in magmatic rocks of the Ukrainian Shield

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