scholarly journals Controlling factors of prolonged REE mineralization in the Maoniuping REE deposit: Constraints from alkaline granite in the syenite–carbonatite complex

2022 ◽  
pp. 104705
Author(s):  
Qiang Weng ◽  
He-Cai Niu ◽  
Pan Qu ◽  
Ning-Bo Li ◽  
Qiang Shan ◽  
...  
Keyword(s):  
Controlling Factors ◽  
Carbonatite Complex ◽  
Alkaline Granite ◽  
Ree Mineralization

scholarly journals Magmatic-Hydrothermal Processes Associated with Rare Earth Element Enrichment in the Kangankunde Carbonatite Complex, Malawi

Minerals ◽  
2019 ◽  
Vol 9 (7) ◽  
pp. 442 ◽  
Author(s):  
Frances Chikanda ◽  
Tsubasa Otake ◽  
Yoko Ohtomo ◽  
Akane Ito ◽  
Takaomi D. Yokoyama ◽  
...  
Keyword(s):  
Rare Earth ◽  
Geochemical Data ◽  
Carbonatite Complex ◽  
Compositional Zoning ◽  
Ree Mineralization ◽  
Hydrothermal Processes ◽  
Magmatic Stage ◽  
Isotope Study ◽  
Late Magmatic Stage ◽  
Element Enrichment

Carbonatites undergo various magmatic-hydrothermal processes during their evolution that are important for the enrichment of rare earth elements (REE). This geochemical, petrographic, and multi-isotope study on the Kangankunde carbonatite, the largest light REE resource in the Chilwa Alkaline Province in Malawi, clarifies the critical stages of REE mineralization in this deposit. The δ56Fe values of most of the carbonatite lies within the magmatic field despite variations in the proportions of monazite, ankerite, and ferroan dolomite. Exsolution of a hydrothermal fluid from the carbonatite melts is evident based on the higher δ56Fe of the fenites, as well as the textural and compositional zoning in monazite. Field and petrographic observations, combined with geochemical data (REE patterns, and Fe, C, and O isotopes), suggest that the key stage of REE mineralization in the Kangankunde carbonatite was the late magmatic stage with an influence of carbothermal fluids i.e. magmatic–hydrothermal stage, when large (~200 µm), well-developed monazite crystals grew. The C and O isotope compositions of the carbonatite suggest a post-magmatic alteration by hydrothermal fluids, probably after the main REE mineralization stage, as the alteration occurs throughout the carbonatite but particularly in the dark carbonatites.

scholarly journals Mineralogy of Phoscorites of the Arbarastakh Complex (Republic of Sakha, Yakutia, Russia)

Minerals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 556
Author(s):  
Mikhail Nikolaevich Kruk ◽  
Anna Gennadievna Doroshkevich ◽  
Ilya Romanovich Prokopyev ◽  
Ivan Aleksandrovich Izbrodin
Keyword(s):  
Mineral Composition ◽  
Siberian Craton ◽  
Chemical Compositions ◽  
Textural Features ◽  
Carbonatite Complex ◽  
Southwestern Part ◽  
Modal Composition ◽  
Accessory Minerals ◽  
Ree Mineralization ◽  
Primary Minerals

The Arbarastakh ultramafic carbonatite complex is located in the southwestern part of the Siberian Craton and contains ore-bearing carbonatites and phoscorites with Zr-Nb-REE mineralization. Based on the modal composition, textural features, and chemical compositions of minerals, the phoscorites from Arbarastakh can be subdivided into two groups: FOS 1 and FOS 2. FOS 1 contains the primary minerals olivine, magnetite with isomorphic Ti impurities, phlogopite replaced by tetraferriphlogopite along the rims, and apatite poorly enriched in REE. Baddeleyite predominates among the accessory minerals in FOS 1. Zirconolite enriched with REE and Nb and pyrochlore are found in smaller quantities. FOS 2 has a similar mineral composition but contains much less olivine, magnetite is enriched in Mg, and the phlogopite is enriched in Ba and Al. Of the accessory minerals, pyrochlore predominates and is enriched in Ta, Th, and U; baddeleyite is subordinate and enriched in Nb. Chemical and textural differences suggest that the phoscorites were formed by the sequential introduction of different portions of the melt. The melt that formed the FOS 1 was enriched in Zr and REE relative to the FOS 2 melt; the melt that formed the FOS 2 was enriched in Al, Ba, Nb, Ta, Th, U, and, to a lesser extent, Sr.

HYDROTHERMAL REE MINERALIZATION IN THE AMBA DONGAR CARBONATITE COMPLEX, GUJARAT, INDIA

2009 ◽  
Vol 47 (5) ◽  
pp. 1105-1116 ◽  
Author(s):  
A. G. Doroshkevich ◽  
S. G. Viladkar ◽  
G. S. Ripp ◽  
M. V. Burtseva
Keyword(s):  
Carbonatite Complex ◽  
Ree Mineralization ◽  
Amba Dongar

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.

Discrete Zr and REE mineralization of the Baerzhe rare-metal deposit, China

2019 ◽  
Vol 104 (10) ◽  
pp. 1487-1502 ◽  
Author(s):  
Kunfeng Qiu ◽  
Haocheng Yu ◽  
Mingqian Wu ◽  
Jianzhen Geng ◽  
Xiangkun Ge ◽  
...  
Keyword(s):  
Compositional Data ◽  
Oscillatory Zoning ◽  
Magmatic Zircon ◽  
Type Ii ◽  
Magmatic Differentiation ◽  
Alkaline Granite ◽  
Ree Mineralization ◽  
Type Ia ◽  
Magmatic Stage ◽  
The Relationship

Abstract Although REE (lanthanides + Sc + Y) mineralization in alkaline silicate systems is commonly accompanied with Zr mineralization worldwide, our understanding of the relationship between Zr and REE mineralization is still incomplete. The Baerzhe deposit in Northeastern China is a reservoir of REE, Nb, Zr, and Be linked to the formation of an Early Cretaceous, silica-saturated, alkaline intrusive complex. In this study, we use in situ laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) analyses of zircon and monazite crystals to constrain the relationship between Zr and REE mineralization at Baerzhe. Three groups of zircon are identified and are differentiated based upon textural observations and compositional characteristics. Type Ia zircons display well-developed oscillatory zoning. Type Ib zircons are darker in cathodoluminescence images and have more irregular zoning and resorption features than type Ia zircons. In addition, type Ib zircons can locally occur as overgrowths on type Ia zircons. Type II zircons contain irregular but translucent cores and rims with oscillatory zoning that are murky brown in color and occur in aggregates. Textural features and compositional data suggest that types Ia and Ib zircon crystallized at the magmatic stage, with type Ia being least-altered and type Ib being strongly altered. Type II zircons, on the other hand, precipitated during the magmatic to magmatichydrothermal transition. Whereas the magnitude of the Eu anomaly is moderate in the barren alkaline granite, both magmatic and deuteric zircon exhibit pronounced negative anomalies. Such features are difficult to explain exclusively by feldspar fractionation and could indicate the presence of fluid induced modification of the rocks. Monazite crystals occur mostly through replacement of zircon and sodic amphibole; monazite clusters are also present. Textural and compositional evidence suggests that monazite at Baerzhe is hydrothermal. Types Ia and Ib magmatic zircon yield 207Pb-corrected 206Pb/238U ages of 127.2 ± 1.3 and 125.4 ± 0.7 Ma, respectively. Type II deuteric zircon precipitated at 124.9 ± 0.6 Ma. The chronological data suggest that the magmatic stage of the highly evolved Baerzhe alkaline granite lasted less than two million years. Hydrothermal monazite records a REE mineralization event at 122.8 ± 0.6 Ma, approximately 1 or 2 million years after Zr mineralization. We therefore propose a model in which parental magmas of the Baerzhe pluton underwent extensive magmatic differentiation while residual melts interacted with aqueous hydrothermal fluids. Deuteric zircon precipitated from a hydrosilicate liquid, and subsequent REE mineralization, exemplified by hydrothermal monazite, correlates with hydrothermal metasomatic alteration that postdated the hydrosilicate liquid event. Such interplay between magmatic and hydrothermal processes resulted in the formation of discrete Zr and REE mineralization at Baerzhe.

REE mineralization in the carbonatites of the sung valley ultramafic-alkaline-carbonatite complex, Meghalaya, India

2014 ◽  
Vol 6 (4) ◽  
Author(s):  
Mohd. Sadiq ◽  
A. Ranjith ◽  
Ravi Umrao
Keyword(s):  
Nepheline Syenite ◽  
Large Scale ◽  
Trace Element Geochemistry ◽  
Economic Potential ◽  
Carbonatite Complex ◽  
Element Geochemistry ◽  
Ree Mineralization ◽  
The Core ◽  
Jaintia Hills ◽  
Intrusive Phase

AbstractThe Early Cretaceous Sung Valley Ultramafic-Alkaline-Carbonatite (SUAC) complex intruded the Proterozoic Shillong Group of rocks and located in the East Khasi Hills and West Jaintia Hills districts of Meghalaya. The SUAC complex is a bowl-shaped depression covering an area of about 26 km2 and is comprised serpentinised peridotite forming the core of the complex with pyroxenite rim. Alkaline rocks are dominantly ijolite and nepheline syenite, occur as ring-shaped bodies as well as dykes. Carbonatites are, the youngest intrusive phase in the complex, where they form oval-shaped bodies, small dykes and veins. During the course of large scale mapping in parts of the Sung Valley complex, eleven carbonatite bodies were delineated. These isolated carbonatite bodies have a general NW-SE and E-W trend and vary from 20–125 m long and 10–40 m wide. Calcite carbonatite is the dominant variety and comprises minor dolomite and apatite and accessory olivine, magnetite, pyrochlore and phlogopite. The REE-bearing minerals identified in the Sung Valley carbonatites are bastnäsite-(Ce), ancylite-(Ce), belovite-(Ce), britholite-(Ce) and pyrochlore that are associated with calcite and apatite. The presence of REE carbonates and phosphates associated with REE-Nb bearing pyrochlore enhances the economic potential of the Sung Valley carbonatites. Trace-element geochemistry also reveals an enrichment of LREEs in the carbonatites and average ΣREE value of 0.102% in 26 bed rock samples. Channel samples shows average ΣREE values of 0.103 wt%. Moreover, few samples from carbonatite bodies has indicated relatively higher values for Sn, Hf, Ta and U. Since the present study focuses surface evaluation of REE, therefore, detailed subsurface exploration will be of immense help to determine the REE and other associated mineralization of the Sung Valley carbonatite prospect.

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