Evolution of pyrochlore in carbonatites of the Amba Dongar complex, India.

Viladkar, Shrinivas G.; Sorokhtina, N. V.

doi:10.1180/mgm.2021.50

Cited by 10 publications

(3 citation statements)

References 57 publications

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“…Haast River, New Zealand, is a carbonatite that intruded as part of a wider Cenozoic province of alkaline rocks (Cooper, 2020). Amba Dongar, Gujarat, India, is a carbonatite that is related to the Deccan Traps (Chandra et al., 2017), intruded around the Mesozoic–Cenozoic boundary, and is particularly known for its potentially economic mineralization of REE, fluorite, and Nb (Dhote et al., 2021; Patel et al., 2022; Viladkar & Sorokhtina, 2021). For both carbonatites, mantle metasomatism occurred in the Mesozoic (Banerjee & Chakrabarti, 2019; Chandra et al., 2017; McCoy‐West et al., 2016; van der Meer et al., 2017), at a time when Ce‐anomalous sediments were widespread on the sea floor (K. Zhang & Shields, 2022).…”

Section: Discussionmentioning

confidence: 99%

A Global Marine Sediment Compilation and a Cerium Anomaly Perspective on Metasomatized Mantle Sources for REE‐Mineralized Carbonatites

Anenburg,

Liu

2024

JGR Solid Earth

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Rare earth elements (REE) are vital for powerful permanent magnets used in electric motors and wind turbines. These elements are chiefly sourced from carbonatites and their weathering products. The economic attractiveness of carbonatites is explained by the 10,000‐fold enrichment of REE in their mineralized portions relative to the average continental crust. Carbonatites form from mantle‐derived melts, but the ultimate origin of their REE is not completely clear. One widely cited model invokes subduction of marine sediments which accumulate REE‐rich material, priming the mantle to produce REE‐rich carbonatite melts which subsequently form deposits in the upper crust. Here we examine a global marine sediment compilation, revealing a wide variety in REE abundances and patterns. We use the sensitive lambda method that separates REE pattern curvature from redox‐related element anomalies to examine both marine sediments and presumably derived carbonatite rocks. We find that the most REE‐rich marine sediments are characterized by strongly negative Ce anomalies, which if recycled via subduction, mineralized carbonatites are expected to inherit. In contrast, we find that mineralized carbonatite rocks do not contain Ce anomalies. This indicates that the REE from the most REE‐rich marine sediments are not recycled into carbonatite deposits, and a different REE source is needed to explain carbonatite fertilities. We also find evidence that raises questions on whether any sediment‐derived REE are present in carbonatite deposits to a significant amount. We suggest that a REE‐rich source may not be required and REE enrichment occurs primarily during crustal magmatic differentiation.

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Section: Discussionmentioning

confidence: 99%

A Global Marine Sediment Compilation and a Cerium Anomaly Perspective on Metasomatized Mantle Sources for REE‐Mineralized Carbonatites

Anenburg,

Liu

2024

JGR Solid Earth

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“…In carbonatites and syenites, pyrochlore crystallizes mainly directly in the magma, leading to metallogenic mechanisms related to Nb mineralization focusing on magmatic evolution e.g., [27]. However, the alteration of pyrochlore also indicates the significant role of hydrothermal fluids on Nb mineralization e.g., [25,26,28,[47][48][49][50][51]. For instance, the pyrochlore in the St Honoré carbonatite in Canada exhibited irregular patchy zoning and overgrowth representing species that crystallized from a carbonatitic magma that had undergone fluid exsolution [47].…”

Section: Genesis Of Four Types Of Pyrochlores In the Miyi Pegmatitementioning

confidence: 99%

Mineral Chemistry of Pyrochlore Supergroup Minerals as Records of Nb Mineralization Processes in NYF-Type Pegmatites: A Case Study of the Emeishan Large Igneous Province, SW China

Yin,

Sun,

Wang

et al. 2023

Minerals

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Alkaline igneous rocks have become a potentially important source of Nb, except for the carbonatites. The metallogenetic mechanism of Nb during the magmatic-hydrothermal evolution of alkaline rocks remains ambiguous. From the perspective of Nb minerals, the mineral chemistry of pyrochlore supergroup minerals provides the mineralogical evidence for indicating the respective contributions of magma and hydrothermal fluids to Nb mineralization. In the Miyi County of the Panzhihua-Xichang (Pan-Xi) area, the central zone of the Permian Emeishan large igneous province (ELIP) in SW China, hundreds of Nb-Y-F mineralized pegmatites (NYF-type) are exposed. This study conducted in situ mineral chemistry analyses on four types of pyrochlores to elucidate the Nb mineralization process. Both Pcl-I and Pcl-II exhibit well-developed oscillatory zoning (OZ), representing magmatic pyrochlore formed through disequilibrium crystallization in an oscillatory environment. Pcl-III, with a homogeneous and less variable composition, is also considered of magmatic origin due to its coherent chemical evolution with Pcl-II. Pcl-IV is considered of hydrothermal origin based on its irregular zoning texture, extremely high Na2O contents, and compositional gap compared with magmatic types. The decrease in TiO2 contents, coupled with the increase in Na2O, F, and Nb2O5 contents from Pcl-I to Pcl-III and from the core to the rim of zoned Pcl-II, indicates that fractional crystallization facilitates the crystallization of albite and the enrichment of volatiles, as well as the precipitation of Nb from the early to late stages. During the magmatic-hydrothermal transition stage, the reductive, Na- and F-enriched fluid transports Nb more effectively, leading to further Nb enrichment in pyrochlore. Consequently, there are two-stage Nb mineralization processes associated with the magmatic-hydrothermal evolution in the Miyi pegmatite, with the primary magmatic ore assemblages being the dominant Nb mineralization, which may be a general model for the mineralization of NYF-type pegmatites.

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“…This locality is a rare example of carbonatites where pyrochlore lacks low-temperature alteration and metamictisation. The paper by Viladkar and Sorokhtina (2021) describes pyrochlore from the Amba Dongar carbonatites in India. The authors discuss compositional evolution from primary magmatic to diverse late-stage hydrothermal minerals and compare new data with published data for pyrochlore from other Indian carbonatites.…”

mentioning

confidence: 99%

Mineralogy and petrology of alkaline rocks and carbonatites: Celebrating the life and work of Gregory Yu. Ivanyuk (1966–2019)

Zaitsev

Chakhmouradian

Krivovichev

et al. 2021

MinMag

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This issue of Mineralogical Magazine is dedicated to the memory of Gregory (Grisha) Yu. Ivanyuk (1966-2019, an internationally acclaimed mineralogist, an accomplished artist and photographer, and a tireless explorer of the Kola wilderness (Fig. 1). Grisha passed away suddenly on July 7, 2019, during a field excursion to Mt. Eveslogchorr in the Khibiny (also known as Khibina) alkaline complex, Kola Peninsula, Russia. This was the very place where he started his mineralogical studies of the region back in 1988. At the time of his untimely death, he was bursting with energy, plans and ideas. None of us who knew him could expect such a sudden and unjust disruption of this singularly dynamic life and research career.Gregory was born on February 23, 1966, in Perm, a city with a 300-year history of mineral exploration which is also the namesake of the Permian Period and stratigraphic system. In 1983, he enrolled at the Faculty of Geology in Leningrad State University (LGU, now St. Petersburg State University), where he majored in Mineralogy. During these formative years, Gregory became first exposed to, and fell in love with, alkaline rocks and carbonatites, particularly after his trip to the Murun charoite deposit in Siberia. This interest was fermented by his research supervisors, Professor Andrei G. Bulakh (1933-2020) and Dr. Mikhail D. Evdokimov (1940-2011, whose scientific interests included the mineralogy and petrology of world-famous alkaline intrusions in the Kola Peninsula, northern Karelia and East Siberia. Not surprisingly, Gregory's first peer-reviewed publication was a study of Murun pyroxenes, beautifully illustrated with his own hand drawings (Ivanyuk and Evdokimov, 1991).Gregory graduated in 1988, back in the days when university graduates were expected to 'work off' their free education for three years at an assigned place of employment, sometimes quite remote from one's home or Alma Mater. Gregory was fortunate enough to land a job at the Geological Institute of the Kola Branch of the USSR Academy of Sciences in Apatity, a mediumsized town of scientists and miners in the foothills of the worldfamous Khibiny mountains. Located in the heart of the Kola

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Evolution of pyrochlore in carbonatites of the Amba Dongar complex, India.

Abstract: This is a 'preproof' accepted article for Mineralogical Magazine. This version may be subject to change during the production process.

Cited by 10 publications

References 57 publications

A Global Marine Sediment Compilation and a Cerium Anomaly Perspective on Metasomatized Mantle Sources for REE‐Mineralized Carbonatites

A Global Marine Sediment Compilation and a Cerium Anomaly Perspective on Metasomatized Mantle Sources for REE‐Mineralized Carbonatites

Mineral Chemistry of Pyrochlore Supergroup Minerals as Records of Nb Mineralization Processes in NYF-Type Pegmatites: A Case Study of the Emeishan Large Igneous Province, SW China

Mineralogy and petrology of alkaline rocks and carbonatites: Celebrating the life and work of Gregory Yu. Ivanyuk (1966–2019)

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