Geochemical Evolution and Ore-Bearing Metasomatites of the Bag-Gazryn Multiphase Array of Rare-Metal Li-F-Granites (Mongolia)

A comparative study of the zircon composition and texture in granites of a three-stage Late Cretaceous magmatism in the Chaun area, Chukotka, Russia, was conducted in biotite granites (BG), quartz monzonites-monzogranites (MG), and zinnwaldite granites (ZG). The significance of the study entails determining the mineralogical indicators of similar granitoids in areas of multi-stage petrogenesis. It is shown that in the rock series of Northern Chukotka, BG → MG → ZG, a morphological evolution of zircon takes place: a reduction in size, elongation, a growing complexity of the crystallography, and an individual texture. In later generations of zircon, as a result of the recrystallization and metasomatism, rare-metal overgrowths, defects in the crystal structure, pores and fissures, and mineral inclusions appear, whereas the crystal-face indices and patterns become more complicated. We can observe the geochemical evolution of zircon: a gradual change in the concentration of trace elements (Hf, U, Y, Th, Nb, and Ti), rare earth elements (Yb, Er, and Dy, as well as Ce and Nd), and uncommon elements (Ca and Al). Rare elements (REE, Y, Hf, Nb, U, and Th) at the post-magmatic stage of the regional history acquired economic abundances. Zircon is therefore indicative of productive ore-magmatic systems.

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The Petrological and Geochemical Evolution of Ediacaran Rare‐Metal Bearing A‐type Granites from the Jabal Aja Complex, Northern Arabian Shield, Saudi Arabia

Acta Geologica Sinica - English Edition ◽

10.1111/1755-6724.13825 ◽

2020 ◽

Vol 94 (3) ◽

pp. 743-762 ◽

Cited By ~ 4

Author(s):

Shehta E. ABDALLAH ◽

Mokhles K. AZER ◽

Abdullah S. AL SHAMMARI

Keyword(s):

Saudi Arabia ◽

Rare Metal ◽

Geochemical Evolution ◽

Arabian Shield

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Geochemical Evolution and Ore-Bearing Metasomatic Rocks of the Baga-Gazryn Multiphase Massif of Rare-Metal Li–F Granites (Mongolia)

Doklady Earth Sciences ◽

10.1134/s1028334x18110168 ◽

2018 ◽

Vol 483 (1) ◽

pp. 1468-1472 ◽

Cited By ~ 1

Author(s):

V. S. Antipin ◽

M. I. Kuzmin ◽

D. Odgerel ◽

L. V. Kousch ◽

A. B. Perepelov

Keyword(s):

Rare Metal ◽

Geochemical Evolution

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Pan-African rare metals bearing pegmatites in Wadi Ghadir, South Eastern desert, Egypt: the geochemical evolution and implications for mineralization

SN Applied Sciences ◽

10.1007/s42452-021-04414-w ◽

2021 ◽

Vol 3 (4) ◽

Author(s):

Mohamed S. Kamar ◽

Nasser M. Moghazy ◽

Gehad M. Saleh

Keyword(s):

Eastern Desert ◽

Rare Metal ◽

Heavy Minerals ◽

Geochemical Evolution ◽

Low Degree ◽

Wall Zone ◽

History Of ◽

High Level ◽

Wadi Ghadir ◽

Rare Metal Pegmatite

AbstractQuartz-diorites, monzogranites and pegmatites are the main rock units in the studied area. The pegmatites occur as zoned pockets within monzogranites with zonal arrangement: border, wall, intermediate, and core zones. The wall zone have enrichment of radioactive and RREs-bearing minerals. K-feldspar, plagioclase and quartz are essential minerals, whereas uranothorite, columbite, zircon, xenotime, monazite, sphalerite and pyrite are accessories. Geochemically, the pegmatites of W. Ghadir have peraluminous character, ferroan with alkalic–calcic affinity and emplaced in within plate setting. These pegmatites revealed Li-bearing variety and high level of rare earth elements mineralization. The studied pegmatites exhibit high contents of Li, Nb, Cu, Ta, U, Th, Pb, Zr, Zn and Ga, can be from the previous data, the studied pegmatites can be classified as a Niobium–Yttrium–Fluorine (NYF) pegmatite or rare metal pegmatite. The trace elements ratio supports a low degree of fractionation and metasomatism in the evolutionary history of the pegmatites, and the very low Cs values (2.2–4.3 ppm) indicate paucity of alkali metal fractionation. Spectrometric investigation revealed that monzogranites are not uraniferous, while the radioactive anomaly is confined to the pegmatites. Applying the U mobilization equation proved that pegmatite samples have been originated from a late magmatic phase of magma very rich in radioelements, and the pegmatites affected with hydrothermal solutions rich in uranium than thorium which indicates uranium addition. Radioactive and important heavy minerals are represented by uranothorite, columbite, zircon, monazite, xenotime, sphalerite and pyrite.

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Early Mesozoic Rare-Metal Granites and Metasomatites of Mongolia: Mineral and Geochemical Features and Hosted Ore Mineralization (Baga Gazriin Chuluu Pluton)

Russian Geology and Geophysics ◽

10.2113/rgg20194162 ◽

2021 ◽

Vol 62 (9) ◽

pp. 1061-1073

Author(s):

V.S. Antipin ◽

L.V. Kushch ◽

D. Odgerel ◽

O.Yu. Belozerova

Keyword(s):

Early Stage ◽

Analytical Data ◽

Rare Metal ◽

Geochemical Evolution ◽

Granitic Magma ◽

Crustal Material ◽

Early Mesozoic ◽

Ore Mineralization ◽

Mantle Fluids ◽

The Impact

Abstract —We present results of petrographic, mineralogical, and geochemical study of all types of rocks of a multiphase pluton and consider the chemical evolution of igneous and metasomatic rocks of the Baga Gazriin Chuluu pluton, based on new precise analytical data. At the early stage of their formation, the pluton granites were already enriched in many trace elements (Li, Rb, Cs, Be, Nb, Ta, Th, and U), F, and HREE relative to the upper continental crust. They show strong negative Ba, Sr, La, and Eu anomalies, which is typical of rare-metal Li–F granites. The geochemical evolution of the Baga Gazriin Chuluu multiphase pluton at the postmagmatic stage was marked by the most intense enrichment of greisens and microclinites with lithophile and ore elements (Sn, W, and Zn) and the formation of ore mineralization. In the permeable rift zone where the Baga Gazriin Chuluu pluton is located, the fluid–magma interaction took place under the impact of a mantle plume. High-temperature mantle fluids caused melting of the crustal substratum, which determined the geochemical specifics of Li–F granite intrusions. Genesis of granitic magma enriched in Li, F, Rb, Sn, and Ta is possible at the low degrees of melting of the lower crustal substratum. The Baga Gazriin Chuluu pluton formed in the upper horizons of the Earth’s crust, where magma undergoes strong differentiation and the saturation of fluids with volatiles can lead to the postmagmatic formation of metasomatites of varying alkalinity (zwitters (greisens), microclinites, and albitites) producing rare-metal mineralization. By the example of the early Mesozoic magmatism area of Mongolia, it is shown that the formation of granites and associated rare-metal minerals is due to the interaction of mantle fluids with the crustal material and the subsequent evolution of granitic magmas.

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