Zirconology of calcite carbonatite of the Vishnevogorsk massif, southern Urals

Краснобаев, А. А.; Rusin, A. I.; Valizer, P. M.; Busharina, S. V.

doi:10.1134/s1028334x10030268

Cited by 14 publications

(8 citation statements)

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“…In addition, black Miass pyrochlores from the Ilmen Mountains in the southern Urals, Russia, showed a glassy luster of their idiomorphic octahedral shape. Ages were reported as 432 ± 12 Ma [75]. Schelingen pyrochlore was selected as a crystalline reference, the Panda Hill sample as a weakly radiation-damaged, the Blue River pyrochlore as a heavily damaged, containing some ordered crystalline areas, and Miass pyrochlore as a fully-amorphous sample.…”

Section: Sample Descriptionmentioning

confidence: 99%

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Thermal annealing of natural, radiation-damaged pyrochlore

Zietlow

Beirau

Mihailova

et al. 2016

Zeitschrift Für Kristallographie - Crystalline Materials

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Radiation damage in minerals is caused by the α-decay of incorporated radionuclides, such as U and Th and their decay products. The effect of thermal annealing (400-1000 K) on radiation-damaged pyrochlores has been investigated by Raman scattering, X-ray powder diffraction (XRD), and combined differential scanning calorimetry/thermogravimetry (DSC/TG). The analysis of three natural radiation-damaged pyrochlore samples from Miass/Russia [6.4 wt% Th, 23.1 · 10 18 α-decay events per gram (dpg)], Panda Hill/Tanzania (1.6 wt% Th, 1.6 · 10 18 dpg), and Blue River/Canada (10.5 wt% U, 115.4 · 10 18 dpg), are compared with a crystalline reference pyrochlore from Schelingen (Germany). The type of structural recovery depends on the initial degree of radiation damage (Panda Hill 28 %, Blue River 85 % and Miass 100 % according to XRD), as the recrystallization temperature increases with increasing degree of amorphization. Raman spectra indicate reordering on the local scale during annealing-induced recrystallization. As Raman modes around 800 cm −1 are sensitive to radiation damage . The most radiation damaged pyrochlore (Miass) shows an abrupt recovery of both, its short-(Raman) and long-range order (X-ray) between 800 and 850 K, while the weakly damaged pyrochlore (Panda Hill) begins to recover at considerably lower temperatures (near 500 K), extending over a temperature range of ca. 300 K, up to 800 K (Raman). The pyrochlore from Blue River shows in its initial state an amorphous X-ray diffraction pattern superimposed by weak Bragg-maxima that indicates the existence of ordered regions in a damaged matrix. In contrast to the other studied pyrochlores, Raman spectra of the Blue River sample show the appearance of local modes above 560 K between 700 and 800 cm −1 resulting from its high content of U and Ta impurities. DSC measurements confirmed the observed structural recovery upon annealing. While the annealing-induced ordering of Panda Hill begins at a lower temperature (ca. 500 K) the recovery of the highly-damaged pyrochlore from Miass occurs at 800 K. The Blue-River pyrochlore shows a multi-step recovery which is similarly seen by XRD. Thermogravimetry showed a continuous mass loss on heating for all radiation-damaged pyrochlores (Panda Hill ca. 1 %, Blue River ca. 1.5 %, Miass ca. 2.9 %).

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Section: Sample Descriptionmentioning

confidence: 99%

“…The only sample containing larger amount of U and Ta is from Blue River, while the other pyrochlore samples rather contain Th-and Ti-impurities. From the actinide content measured by EMP (Table 1) and geologic age the total radiation dose can be calculated using α-decays of the Krasnobaev et al [75].…”

Section: Sample Descriptionmentioning

confidence: 99%

Thermal annealing of natural, radiation-damaged pyrochlore

Zietlow

Beirau

Mihailova

et al. 2016

Zeitschrift Für Kristallographie - Crystalline Materials

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“…A close U-Pb age of 432±1.5 Ma was obtained for zircons from ultramafic rocks of the Buldym complex [21]. IVC carbonatites were dated at 432±12 [22], 419±20 [23], and 417±3 Ma [24] (U-Pb method, zircons). A younger age, 388±52 Ma (D2), was obtained for carbonatites by the Sm-Nd method [17].…”

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confidence: 75%

Carbonatite complexes of the South Urals: geochemical features, ore mineralization, and geodynamic settings

Nedosekova

2022

PMI

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The article presents the results of study of the Ilmeno-Vishnevogorsky and Buldym carbonatite complexes in the Urals. It has been established that the carbonatites of the Ilmeno-Vishnevogorsky complex are represented by high-temperature calciocarbonatites (sövites I and II) with pyrochlore ore mineralization. U-Ta-rich populations of uranium pyrochlores (I) and fluorocalciopyrochlores (II) crystallize in miaskite-pegmatites and sövites I; fluorocalciopyrochlores (III) and Sr-REE-pyrochlores (IV) of late populations form in sövites II. In the Buldym complex, along with high-temperature calciocarbonatites containing fluorocalciopyrochlore (III), medium-temperature varieties of magnesiocarbonatites with REE-Nb mineralization (monazite, niobo-aeschynite, columbite, etc.) are widespread. Miaskites and carbonatites of the Urals are characterized by high contents of LILE (Sr, Ba, K, Rb) and HFSE (Nb, Ta, Zr, Hf, Ti), which are close to the contents in rift-related carbonatite complexes of intraplate settings and significantly differ from synorogenic collisional carbonatite complexes. The Ural carbonatite complexes formed on continental rift margins during the opening of the Ural Ocean at the time of transition from extensional to compressional tectonics. Later on, they were captured and deformed in the suture zone as a result of collision. Plastic and brittle deformations, anatexis, recrystallization of rocks and ores of carbonatite complexes in the Urals are associated with orogenic and post-collision settings.

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“…Конкордантный U-Pb-возраст основной генерации циркона (Zr1), с крупноосцилляторной зональностью: 280±8 млн лет (P 1 ), СКВО=0.0014, n =13 (рис. 2-II, б), подтверждает результаты датирования этого образца миаскит-пегматита Rb-Sr-методом (274±5 млн лет) и наиболее близок возрасту поздних генераций циркона в карбонатитах и миаскит-пегматитах [Krasnobaev et al, 2010b[Krasnobaev et al, , 2014Nedosekova et al, 2014]. Внешние зоны кристаллов циркона (Zr2), с мелкоосцилляторной зональностью, образующиеся на заключительном этапе рудообразования (см.…”

Section: результаты исследованияunclassified

“…Реликтовые затравки циркона (Zr_relict) (красный пунктир, рис. 2-I, г, д, е, к, м), которые иногда сохраняются в центральной части кристаллов циркона пегматитов, показывают наиболее древний возраст -374±17 млн лет, близкий возрастному кластеру ранних генераций цирконов миаскитов и карбонатитов [Krasnobaev et al, 2010b[Krasnobaev et al, , 2016.…”

Section: результаты исследованияunclassified

AGE AND GEODYNAMIC SETTINGS OF MIASKITE-PEGMATITES, CARBONATITES, AND Nb-Zr MINERALIZATION OF THE ILMENO-VISHNEVOGORSKY ALKALINE COMPLEX, SOUTH URAL (U-Pb AND Rb-Sr ISOTOPE DATA)

Nedosekova

Chervyakovsky

Chervyakovskaya

et al. 2022

Geodin. tektonofiz.

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The Ilmeno-Vishnevogorsky miaskite-phenite-carbonatite complex (IVС), located in the Urals folded region, is a representative of "linear type" carbonatite complexes, with which Nb-Zr deposits are associated. The ore potential of linear carbonatite complexes, the time and duration of ore-forming processes, and the geodynamic setting remain the subject of discussion. In order to estimate the age and duration of ore formation processes in the IVC, the U-Pb dating of zircon (LA-ICP-MS) from miaskite-pegmatites, as well as Rb-Sr dating of ore-bearing (pyrochlore-bearing) varieties of miaskite-pegmatites and carbonatites (ID-TIMS) were carried out. The U-Pb dating of zircon from the IVC miaskite-pegmatites showed the Permian age (280±8 Ma, P1 – age of the main zircon generation). The Rb-Sr-mineral isochron of miaskite-pegmatite showed a close age of 274±5 Ma (P1), confirming the results of U-Pb-dating of miaskite-pegmatites. The Rb-Sr dating of pyrochlore carbonatite varieties (sovites II) showed an age of 250±3 Ma (T1). The results of Rb-Sr- and U-Pb dating indicate that the processes of pegmatite- and carbonatite formation and the associated Zr-Nb ore formation in IVC occurred at the late collisional and postcollisional stage of development of the Ural folded region. Based on the data obtained, the geodynamic model for the IVC formation was proposed.

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Zirconology of calcite carbonatite of the Vishnevogorsk massif, southern Urals

Cited by 14 publications

References 1 publication

Thermal annealing of natural, radiation-damaged pyrochlore

Thermal annealing of natural, radiation-damaged pyrochlore

Carbonatite complexes of the South Urals: geochemical features, ore mineralization, and geodynamic settings

AGE AND GEODYNAMIC SETTINGS OF MIASKITE-PEGMATITES, CARBONATITES, AND Nb-Zr MINERALIZATION OF THE ILMENO-VISHNEVOGORSKY ALKALINE COMPLEX, SOUTH URAL (U-Pb AND Rb-Sr ISOTOPE DATA)

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