Geochronology, Oxidization State and Source of the Daocheng Batholith, Yidun Arc: Implications for Regional Metallogenesis

The Daocheng batholith consists of granite, granodiorite and K-feldspar megacrystic granite, which is located in the north Yidun Arc. It is a barren batholith in contrast to plutons of the same age that contain major copper deposits, such as Pulang to the south. In the Daocheng, abundant mafic microgranular enclaves (MMEs) mainly developed within granodiorite and K-feldspar megacrystic granite, which are characterized by quenched apatite, quartz eyes and plagioclase phenocrysts. LA-ICP-MS zircon U–Pb dating of host granodiorite yielded ages ranging from 223 Ma to 210 Ma, with a weighted mean of 215.3 ± 1.8 Ma. Zircons from MMEs yielded ages ranging from 218 Ma to 209 Ma, with a weighted mean of 214.2 ± 1.4 Ma. Geochemical analyses show that granodiorite is high-K, calc-alkaline and I-type, with SiO2 contents ranging from 67.90% to 70.54%. These rocks are metaluminous to marginally peraluminous (A/CNK = 0.98–1.00) and moderately rich in alkalis with K2O ranging from 3.28% to 4.59% and Na2O ranging from 3.18% to 3.20%, with low MgO (1.08%–1.29%), Cr (12.7 ppm–16.8 ppm), Ni (5.19 ppm–6.16 ppm) and Mg# (35–49). The MMEs have relatively low SiO2 contents (56.34%–60.91%), higher Al2O3 contents (16.06%–17.98%), higher MgO and FeO abundances and are metaluminous (A/CNK = 0.82–0.83). The MMEs and host granodiorite are enriched in light rare-earth elements (LREEs) relative to heavy rare-earth elements (HREEs), with slightly negative Eu anomalies, and enriched in Th, U and large ion lithophile elements (LILEs; e.g., K, Rb and Pb), and depleted in high field strength elements (HFSEs; e.g., Nb, Ta, P and Ti), showing affinities typical of arc magmas. The zircon εHf(t) values (−6.28 to −2.33) and ancient two-stage Hf model ages of 1.92 to 1.25 Ga, indicating that the magmas are generally melts that incorporated significant portions of Precambrian crust. The relatively low silica contents and high Mg# values of the MMEs, and the linear patterns of MgO, Al2O3 and Fe2O3 with SiO2 between the MMEs and host granodiorite, showing the formation of MMEs are genetically related to magma mixing. The Daocheng granodiorite is characterized by much lower zircon Ce4+/Ce3+ (average of 3.53) and low fO2 value (average of ∆FMQ = –10.84), whereas the ore-bearing quartz monzonite porphyries in the Pulang copper deposit are characterized by much higher zircon Ce4+/Ce3+ (average of 52.10) and high fO2 value (average of ∆FMQ = 2.8), indicating the ore-bearing porphyry intrusions had much higher fO2 of magma than the ore-barren intrusions considering that the high oxygen fugacity of the magma is conducive to mineralization.

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Zircon U–Pb and molybdenite Re–Os dating and geological implications of the Shimadong porphyry molybdenum deposit in eastern Yanbian, northeastern China

Canadian Journal of Earth Sciences ◽

10.1139/cjes-2019-0014 ◽

2020 ◽

Vol 57 (5) ◽

pp. 630-646

Author(s):

Xi-Tao Nie ◽

Jing-Gui Sun ◽

Feng-Yue Sun ◽

Bi-Le Li ◽

Ya-Jing Zhang ◽

...

Keyword(s):

Rare Earth ◽

Rare Earth Elements ◽

Lower Crust ◽

Active Continental Margin ◽

Major And Trace Elements ◽

Northeastern China ◽

Heavy Rare Earth ◽

The North ◽

Heavy Rare Earth Elements ◽

Porphyry Mo Deposit

The Shimadong porphyry Mo deposit is located in eastern Yanbian, in the eastern part of the north margin of the North China craton, northeastern China. Here, we present the whole-rock major and trace elements, zircon U–Pb and Hf isotope data, and molybdenite Re–Os data for the Shimadong deposit. The porphyry was emplaced at 163.7 ± 0.9 Ma and the mineralization at 163.1 ± 0.9 Ma, suggesting that the mineralization was associated with the emplacement of the Shimadong porphyritic monzogranite. The porphyritic monzogranite had high SiO2 (70.09–70.55 wt%) and K2O + Na2O (7.98–8.27 wt%) contents and low MgO (0.51–0.53 wt%), TFeO (2.4–2.47 wt%), CaO (2.19–2.26 wt%), and K2O/Na2O (0.8–0.82) contents. The porphyry was rich in large ion lithophile elements Rb, Ba, K, and Sr, depleted in high-field-strength elements Y, Nb, Ta, P, and Ti, without significant Eu anomaly (δEu = 0.86–1.00), and depleted in heavy rare earth elements with light rare earth elements/heavy rare earth elements = 18.25–20.72 and (La/Yb)N = 27.10–34.67. These features are similar to those of adakitic rocks derived from a thickened lower crust. Zircon εHf(t) values for the porphyritic monzogranite ranged from –19.2 to 6.3, and the two-stage Hf model ages (TDM2) were 2421–811 Ma. These data indicate that the primary magma of the Shimadong porphyritic monzogranite was mainly derived from partial melting of the thickened lower crust consisting of juvenile crust and pre-existing crust. Combined with the results of previous studies, our data suggest that the Shimadong porphyry Mo deposit was emplaced along an active continental margin related to the westward subduction of the paleo-Pacific Plate.

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Petrografia, Geoquímica, Análises Isotópicas (Sr, Nd) e Geocronologia Ar-Ar dos Basaltos de Tapirapuã (Tangará da Serra, Mato Grosso, Brasil)

Pesquisas em Geociências ◽

10.22456/1807-9806.19515 ◽

2006 ◽

Vol 33 (2) ◽

pp. 71 ◽

Cited By ~ 4

Author(s):

MÁRCIA APARECIDA DE SANT’ANA BARROS ◽

ANA MARIA MIZUSAKI ◽

RICARDO WESKA ◽

ANDRÉ DE BORBA ◽

FARID CHEMALE JR ◽

...

Keyword(s):

Rare Earth ◽

Rare Earth Elements ◽

North Atlantic ◽

Volcanic Event ◽

Mato Grosso ◽

Fine Grained ◽

The North ◽

Tectonic Environment ◽

Heavy Rare Earth Elements ◽

Light Rare Earth Elements

The basaltic flows from Tapirapuã Formation are exposed at Tangará da Serra region, 250 km from Cuiabá (MT) and the thickness can reach 310 meters. The basalts range from massive dark gray, with colunar disjunctions at the base to purple amygdaloidal at the top. They are generally fine-grained, however gabroics portions have been identified. In thin section the Tapirapuã basalts show subophitic texture. Chemical analyses in these rocks suggest tholeiitic compositions, within continental tectonic environment. There is an enrichment of light rare earth elements when compared to heavy rare earth elements. The studied samples have low contents of TiO2 and P2O5 being similar to low P2O5 and TiO2 group from Serra Geral Formation (Paraná Basin). Analyses of Sr and Nd isotopes show the following results: 87Sr/86Sr between 0.703 and 0.707, ∈Nd from –0.01 to + 2.32 and model ages (TDM)= (931 to 1.267 Ma). 40Ar / 39Ar geochronology of plagioclase crystals from Tapirapuã basalts presented a plateau age of 206 ± 6 Ma, in agreement with previous ages obtained from Anari and Tapirapuã sub-provinces. This result places the volcanic event at the limit of the Triassic-Jurassic periods, related to the opening of the North Atlantic.

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Metallogenic Epoch and Tectonic Setting of Saima Niobium Deposit in Fengcheng, Liaoning Province, NE China

Minerals ◽

10.3390/min9020080 ◽

2019 ◽

Vol 9 (2) ◽

pp. 80 ◽

Cited By ~ 3

Author(s):

Nan Ju ◽

Yun-Sheng Ren ◽

Sen Zhang ◽

Zhong-Wei Bi ◽

Lei Shi ◽

...

Keyword(s):

Rare Earth ◽

Rare Earth Elements ◽

Nepheline Syenite ◽

Large Scale ◽

Tectonic Setting ◽

Liaoning Province ◽

Late Triassic ◽

Ne China ◽

The North ◽

Heavy Rare Earth Elements

The Saima deposit is a newly discovered niobium deposit which is located in the eastern of Liaoning Province, NE China. Its mineralization age and geochemical characteristics are firstly reported in this study. The Nb orebodies are hosted by the grey–brown to grass-green aegirine nepheline syenite. Detailed petrographical studies show that the syenite consists of orthoclase (~50%), nepheline (~30%), biotite (~15%) and minor arfvedsonite (~3%) and aegirine (~2%), with weak hydrothermal alteration dominated by silicification. In situ LA-ICP-MS zircon U-Pb dating indicates that the aegirine nepheline syenite was emplaced in the Late Triassic (229.5 ± 2.2 Ma), which is spatially, temporally and genetically related to Nb mineralization. These aegirine nepheline syenites have SiO2 contents in the range of 55.86–63.80 wt. %, low TiO2 contents of 0.36–0.64 wt. %, P2O5 contents of 0.04–0.11 wt. % and Al2O3 contents of more than 15 wt. %. They are characterized by relatively high (K2O + Na2O) values of 9.72–15.51 wt. %, K2O/Na2O ratios of 2.42–3.64 wt. % and Rittmann indexes (σ = [ω(K2O + Na2O)]2/[ω(SiO2 − 43)]) of 6.84–17.10, belonging to the high-K peralkaline, metaluminous type. These syenites are enriched in large ion lithophile elements (LILEs, e.g., Cs, Rb and Ba) and light rare earth elements (LREEs) and relatively depleted in high field strength elements (HFSEs, e.g., Nb, Zr and Ti) and heavy rare earth elements (HREEs), with transitional elements showing an obvious W-shaped distribution pattern. Based on these geochronological and geochemical features, we propose that the ore-forming intrusion associated with the Nb mineralization was formed under post-collision continental-rift setting, which is consistent with the tectonic regime of post-collision between the North China Craton and Paleo-Asian oceanic plate during the age in Ma for Indosinian (257–205 Ma). Intensive magmatic and metallogenic events resulted from partial melting of lithospheric mantle occurred during the post-collisional rifting, resulting in the development of large-scale Cu–Mo mineralization and rare earth deposits in the eastern part of Liaoning Province.

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The role of sulfate-rich fluids in heavy rare earth enrichment at the Dashigou carbonatite deposit, Huanglongpu, China

Mineralogical Magazine ◽

10.1180/mgm.2019.78 ◽

2019 ◽

Vol 84 (1) ◽

pp. 65-80 ◽

Cited By ~ 5

Author(s):

Delia Cangelosi ◽

Martin Smith ◽

David Banks ◽

Bruce Yardley

Keyword(s):

Rare Earth ◽

Rare Earth Elements ◽

Fluid Inclusions ◽

Central China ◽

Open Pit ◽

Secondary Phases ◽

Heavy Rare Earth ◽

The North ◽

Heavy Rare Earth Elements ◽

Total Sulfate

AbstractThe Huanglongpu carbonatites are located in the north-western part of the Qinling orogenic belt in central China. Calcite carbonatite dykes at the Dashigou open pit are unusual due to their enrichment in heavy rare earth elements (HREE) relative to light rare earth elements (LREE), leading to a flat REE pattern, and in that the majority of dykes have a quartz core. They also host economic concentrations of molybdenite. The calcite carbonatite dykes show two styles of mineralogy according to the degree of hydrothermal reworking, and these are reflected in REE distribution and concentration. The REE in the little-altered calcite carbonatite occur mostly in magmatic REE minerals, mainly monazite-(Ce), and typically have ΣLREE/(HREE+Y) ratios from 9.9 to 17. In hydrothermally altered calcite carbonatites, magmatic monazite-(Ce) is partially replaced to fully replaced by HREE-enriched secondary phases and the rocks have ΣLREE/(HREE+Y) ratios from 1.1 to 3.8. The fluid responsible for hydrothermal REE redistribution is preserved in fluid inclusions in the quartz lenses. The bulk of the quartz lacks fluid inclusions but is cut by two later hydrothermal quartz generations, both containing sulfate-rich fluid inclusions with sulfate typically present as multiple trapped solids, as well as in solution. The estimated total sulfate content of fluid inclusions ranges from 6 to >33 wt.% K2SO4 equivalent. We interpret these heterogeneous fluid inclusions to be the result of reaction of sulfate-rich fluids with the calcite carbonatite dykes. The final HREE enrichment is due to a combination of factors: (1) the progressive HREE enrichment of later magmatic calcite created a HREE-enriched source; (2) REE–SO42– complexing allowed the REE to be redistributed without fractionation; and (3) secondary REE mineralisation was dominated by minerals such as HREE-enriched fluorocarbonates, xenotime-(Y) and churchite-(Y) whose crystal structures tends to favour HREE.

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Petrogenesis and U-Pb zircon dating of Chaitma Alkaline Complex from the southern margin of the Central Indian Tectonic Zone: geodynamic implications

Geological Society London Special Publications ◽

10.1144/sp513-2021-28 ◽

2021 ◽

pp. SP513-2021-28

Author(s):

Satya Narayana Mahapatro ◽

M. L. Renjith ◽

Ranjit Kumar Martha ◽

Rakesh Kumar Patel ◽

Dewashish Upadhyay ◽

...

Keyword(s):

Rare Earth ◽

Rare Earth Elements ◽

Magma Mixing ◽

Central India ◽

Alkaline Complex ◽

Tectonic Zone ◽

Southern Margin ◽

Short Period ◽

Heavy Rare Earth Elements ◽

Central Indian Tectonic Zone

AbstractIn this study, we constrain the petrogenesis and U-Pb zircon age of a newly discovered alkaline complex, christened the Chaitma Alkaline Complex at the southern margin of the Central Indian Tectonic Zone in Central India. The Chaitma Alkaline Complex comprises syenites and gabbro, emplaced coevally and show features consistent with magma mixing. Geochemically, syenites are potassic to ultrapotassic (K2O/Na2O: 0.79-3.42) and contain high Ba (∼800 to 2700 ppm) and Sr (∼1400-3200 ppm). They show enrichment of the light rare earth elements (LREE) relative to the heavy rare earth elements (HREE) (La/Yb: 32-103) and do not display Eu-anomaly. Based on their geochemical signatures such as low MgO (<0.87 wt.%), Ni (8-16 ppm) and Cr (7-44 ppm) contents and prominent Zr-Hf negative anomaly, the syenites are inferred to have been derived by partial melting of a carbonated/metasomatised thickened lower crustal source. The coeval gabbros are undersaturated in silica (41-44 wt.%) with relatively high total alkalis (Na2O+K2O: 3.7-5.1 wt.%), Fe2O3 (17-19 wt.%), P2O5 (3.1-4.9 wt.%), Sr (1600-3400 ppm) and Ba (300-3500 ppm) contents. These have low MgO (<4.8 wt.%), Ni (13-30 ppm) and Cr (18-84 ppm). Their chemistry is interpreted to be the result of interaction with the syenitic magma. These geochemical characters along with high LREE/HREE ratio, negative trough in Nb-Ta, Zr-Hf, Ti, Sr and Rb and positive spike of Pb in spider diagram, and enrichment of LILE over HFSE indicate their derivation from metasomatised subduction modified garnet-peridotite mantle source. Our study indicates that syenites and gabbros of the Chaitma Alkaline Complex were formed from genetically unrelated parental magmas derived from distinct sources. U-Pb dating of zircon yielded magmatic emplacement age of 1626±15 Ma for the syenites. The Chaitma Alkaline Complex was presumably formed during a short period of crustal extension in the midst of a protracted period of continent-continent collision and granulite grade metamorphism (c. 1.71-1.58 Ga) at the southern margin of the Central Indian Tectonic Zone.

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REE Geochemical Characteristic of Apatite: Implications for Ore Genesis of the Zhijin Phosphorite

Minerals ◽

10.3390/min10111012 ◽

2020 ◽

Vol 10 (11) ◽

pp. 1012

Author(s):

Liu Xiqiang ◽

Zhang Hui ◽

Tang Yong ◽

Liu Yunlong

Keyword(s):

Rare Earth ◽

Rare Earth Elements ◽

Inductively Coupled Plasma ◽

Ore Deposits ◽

Inductively Coupled ◽

Ree Distribution ◽

Phosphorite Deposit ◽

Heavy Rare Earth Elements ◽

Plasma Mass Spectrometry ◽

Geochemical Analyses

Phosphorite-type rare earth deposits, which are one of the important types of rare earth elements (REE) ore deposits, have attracted increasing attention because of the extreme enrichments in heavy rare earth elements (HREE), including Yttrium (Y). In this study, in situ geochemical analyses of apatite grains from Zhijin phosphorites were conducted using electron probe microanalysis (EMPA) and laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). Based on EPMA mapping analysis, we show that rare earth elements and Yttrium (REY) entering into the crystal lattice by isomorphism rather than by inclusions of REY-bearing accessory minerals. The post-Archean Australian Shales (PAAS)-normalized REY patterns of the apatite grains are characterized by hat-shaped MREE-enriched patterns. We interpret that this pattern may reflect the REE distribution of seawater at that time. We propose that in a local, reducing environment, dramatically increased the concentration of REY in seawater, and resulted in the MREE-enriched patterns in the ancient ocean. The main mechanism for the genesis of the Zhijin phosphorite deposit is the apatite crystallizes during the mixing process of REY- and P-rich fluid and oxidizing seawater.

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Pargasite-bearing vein in spinel lherzolite from the mantle lithosphere of the North America Cordillera

Canadian Journal of Earth Sciences ◽

10.1139/cjes-2018-0239 ◽

2019 ◽

Vol 56 (8) ◽

pp. 870-885 ◽

Cited By ~ 1

Author(s):

Edward D. Ghent ◽

Benjamin R. Edwards ◽

James K. Russell

Keyword(s):

Rare Earth ◽

Rare Earth Elements ◽

Mantle Peridotite ◽

Canadian Cordillera ◽

Spinel Lherzolite ◽

Mantle Lithosphere ◽

Amphibole Composition ◽

The North ◽

Heavy Rare Earth Elements ◽

The Stability

Basanite lavas near Craven Lake, British Columbia, host a spinel lherzolite xenolith containing cross-cutting veins with pargasitic amphibole (plus minor apatite). The occurrence of vein amphibole in spinel lherzolite is singular for the Canadian Cordillera. The vein crosscuts foliated peridotite and is itself cut by the basanite host. The amphibole is pargasite, which is the most common amphibole composition in mantle peridotite. Rare earth element concentrations in the pargasite are similar to those for mafic alkaline rocks across the northern Cordilleran volcanic province (light rare earth elements ∼50× chondrite and heavy rare earth elements ∼5× chondrite). Two-pyroxene geothermometry suggests that the vein and host peridotite were thermally equilibrated prior to sampling by the basanite magma. Calculated temperature conditions for the sample, assuming equilibration along a model steady-state geotherm, are between 990 and 1050 °C and correspond to a pressure of 0.15 GPa (∼52 ± 2 km depth). These conditions are consistent with the stability limits of mantle pargasite in the presence of a fluid having XH2O < ∼0.1. The pargasite vein and associated apatite provide direct evidence for postaccretion fracture infiltration of CO2–F–H2O-bearing silicate fluids into the Cordilleran mantle lithosphere. Pargasite with low aH2O is in equilibrium with parts per million concentrations of H2O in mantle olivine, potentially lowering the mechanical strength of the lithospheric mantle underlying the Cordillera and making it more susceptible to processes such as lithospheric delamination. Remelting of Cordilleran mantle lithosphere containing amphibole veins may be involved in the formation of sporadic nephelinite found in the Canadian Cordillera.

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Intrinsically weak magnetic anisotropy of cerium in potential hard-magnetic intermetallics

npj Quantum Materials ◽

10.1038/s41535-020-00301-6 ◽

2021 ◽

Vol 6 (1) ◽

Author(s):

Anna Galler ◽

Semih Ener ◽

Fernando Maccari ◽

Imants Dirba ◽

Konstantin P. Skokov ◽

...

Keyword(s):

Rare Earth ◽

Rare Earth Elements ◽

Magnetic Anisotropy ◽

High Performance ◽

Kondo Effect ◽

Quantitative Description ◽

Many Body ◽

Heavy Rare Earth Elements ◽

Fe Intermetallics ◽

Full Temperature

AbstractCerium-based intermetallics are currently attracting much interest as a possible alternative to existing high-performance magnets containing scarce heavy rare-earth elements. However, the intrinsic magnetic properties of Ce in these systems are poorly understood due to the difficulty of a quantitative description of the Kondo effect, a many-body phenomenon where conduction electrons screen out the Ce-4f moment. Here, we show that the Ce-4f shell in Ce–Fe intermetallics is partially Kondo screened. The Kondo scale is dramatically enhanced by nitrogen interstitials suppressing the Ce-4f contribution to the magnetic anisotropy, in striking contrast to the effect of nitrogenation in isostructural intermetallics containing other rare-earth elements. We determine the full temperature dependence of the Ce-4f single-ion anisotropy and show that even unscreened Ce-4f moments contribute little to the room-temperature intrinsic magnetic hardness. Our study thus establishes fundamental constraints on the potential of cerium-based permanent magnet intermetallics.

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Statherian (ca. 1714–1680 Ma) Extension-Related Magmatism and Deformation in the Southwestern Korean Peninsula and Its Geological Significance: Constraints from the Petrological, Structural, Geochemical and Geochronological Studies of Newly Identified Granitoids

Minerals ◽

10.3390/min11060557 ◽

2021 ◽

Vol 11 (6) ◽

pp. 557

Author(s):

Byung-Choon Lee ◽

Weon-Seo Kee ◽

Uk-Hwan Byun ◽

Sung-Won Kim

Keyword(s):

Korean Peninsula ◽

Tectonic Setting ◽

Alkali Feldspar ◽

Ductile Deformation ◽

Southwestern Part ◽

The North ◽

Deformation Event ◽

Geochemical Analyses ◽

A Minor ◽

T Values

In this study, petrological, structural, geochemical, and geochronological analyses of the Statherian alkali feldspar granite and porphyritic alkali feldspar granite in the southwestern part of the Korean Peninsula were conducted to examine petrogenesis of the granitoids and their tectonic setting. Zircon U-Pb dating revealed that the two granites formed around 1.71 Ga and 1.70–1.68 Ga, respectively. The results of the geochemical analyses showed that both of the granites have a high content of K2O, Nb, Ta, and Y, as well as high FeOt/MgO and Ga/Al ratios. Both granites have alkali-calcic characteristics with a ferroan composition, indicating an A-type affinity. Zircon Lu-Hf isotopic compositions yielded negative εHf(t) values (−3.5 to −10.6), indicating a derivation from ancient crustal materials. Both granite types underwent ductile deformation and exhibited a dextral sense of shear with a minor extension component. Based on field relationships and zircon U-Pb dating, it was considered that the deformation event postdated the emplacement of the alkali feldspar granite and terminated soon after the emplacement of the porphyritic alkali feldspar granite in an extensional setting. These data indicated that there were extension-related magmatic activities accompanying ductile deformation in the southwestern part of the Korean Peninsula during 1.71–1.68 Ga. The Statherian extension-related events are well correlated with those in the midwestern part of the Korean and eastern parts of the North China Craton.

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