Minerals

Research

Jump to: Review

26 pages, 12140 KiB

Open AccessArticle

Age and Petrogenesis of the Dongjin Rare Metal Mineralized Intrusion in the Northern Margin of the North China Craton

by Chenyu Liu, Gongzheng Chen, Jinfang Wang, Yi Cheng, Kangshuo Li, Zeqian Lu and Yutong Song

Minerals 2023, 13(12), 1477; https://doi.org/10.3390/min13121477 - 24 Nov 2023

Viewed by 1032

Abstract

Highly fractionated granites are widespread in the middle part of the northern margin of the North China Craton (MNNCC), and several are accompanied by rare metal mineralization. The Dongjin rare metal mineralized intrusion, which is representative of this region, is composed of fine-grained [...] Read more.

Highly fractionated granites are widespread in the middle part of the northern margin of the North China Craton (MNNCC), and several are accompanied by rare metal mineralization. The Dongjin rare metal mineralized intrusion, which is representative of this region, is composed of fine-grained alkali-feldspar granite (FAG) and kali-feldspar granite (KG). The FAG and KG evolve continuously, exemplifying the relationship between magmatic evolution and rare metal mineralization. In this contribution, we present integrated columbite U-Pb geochronology, mineralogy, and whole-rock geochemistry analyses of the Dongjin intrusion to determine the timing of the mineralization, petrogenesis, and geodynamic setting, from which the following results are obtained: (1) LA-ICP-MS U-Pb dating for columbite of the FAG and KG yielded the lower intercept ages between 248.9 ± 1.9 Ma and 250.1 ± 1.1 Ma on the Tera–Wasserburg concordia diagram; (2) Geochemically, the Dongjin intrusion is characterized by an enrichment in Si, Al, Rb, Th, U, Nb, and Zr and a strong depletion in Ba, Sr, P, and Ti, with extremely negative Eu anomalies, high LREE and HREE values, and a noticeable tetrad effect of rare earth elements; as a result, it belongs to high-K calc-alkaline rocks; (3) The Dongjin intrusion belongs to a highly differentiated I-type or A-type granite; (4) The fractional crystallization of plagioclase, K-feldspar, and biotite occurred during magmatic evolution; (5) The Dongjin intrusion was formed in a post-collisional extensional environment. In conclusion, the FAG and KG have a homologous evolution, and the FAG has a higher degree of fractional crystallization. The enrichment and mineralization of Nb-Ta are related to the highly fractionated crystallization of granitic magma and fluid–melt interactions in the final stages of magmatic evolution, and there is a rare metal mineralization related to highly fractionated granite in the MNNCC in the Early Triassic, which deserves full attention in future research and prospecting. Full article

(This article belongs to the Special Issue Critical Metals on Land and in the Ocean)

► Show Figures

Figure 1

31 pages, 29088 KiB

Open AccessArticle

Critical Metals Mineralization in the Late-Stage Intrusions of Salmi Batholith, Ladoga Karelia, Russia

by Vasily I. Ivashchenko

Minerals 2023, 13(5), 648; https://doi.org/10.3390/min13050648 - 07 May 2023

Cited by 1 | Viewed by 2033

Abstract

The paper reports the results of studies on critical metal mineralization genetically related to the late-stage intrusions of Salmi anorthosite-rapakivi granite batholith (SARGB) in the Riphean age. In, Bi, and Be mineralization in skarn-greisen deposits and occurrences at the SARGB endocontact, as well [...] Read more.

The paper reports the results of studies on critical metal mineralization genetically related to the late-stage intrusions of Salmi anorthosite-rapakivi granite batholith (SARGB) in the Riphean age. In, Bi, and Be mineralization in skarn-greisen deposits and occurrences at the SARGB endocontact, as well as REE and Nb-Ta mineralization in Li-F granites, understood as the late intrusive phases of the batholith, were studied. It is the first report on columbite-group minerals, as well as REE-Ta-Nb and REE mineralization in SARGB granites. Optical and scanning electron microscopy, EDS and LA ICP MS microanalysis, X-ray fluorescence spectrometry, Raman spectroscopy, and inductively coupled plasma mass spectrometry (ICP-MS) were used. The data obtained show that roquesite formation was mainly triggered by the decay of In-bearing solid sphalerite and chalcopyrite solutions. Zavaritskite, associated with unoxidized sulphides, was derived hypogenically and seldom occurs in ores. A helvine-group mineral association with zinc-enriched spinel (ZnO 22%–25%) seems to have been one of the factors preventing genthelvite formation. The Muzilampi, Hepaoja and Avtodor ore occurrences in Li-F granites display similar REE and Nb-Ta mineralization. They are associated with Y-fluorite and Li-siderophyllite, which contain exceptionally high Nb concentrations (0.25%–0.78%) in Muzilampi granites. Additionally, fluorite-1 is commonly overfilled (to >50%) with micron-sized synchisite and parisite inclusions. Columbite-tantalite-group minerals, present at all the occurrences studied, occur solely as ferricolumbites with a dominant Mn/(Mn + Fe) ratio of <0.2. Biotite and Li-siderophyllite, associated with columbite, have an extremely high iron index Fe/(Fe + Mg) > 0.9 approaching the maximum values (~1.0) in the most differentiated granites. Full article

(This article belongs to the Special Issue Critical Metals on Land and in the Ocean)

► Show Figures

Figure 1

12 pages, 5776 KiB

Open AccessArticle

Influence of Phosphatization in REY Geochemistry in Ferromanganese Crusts in Line Islands, Central Pacific

by Junming Zhou, Shengxiong Yang, Jingya Cao, Yutian Deng, Zhenquan Wei, Yuanheng Li, Dongmei Tian and Guang Hu

Minerals 2023, 13(5), 647; https://doi.org/10.3390/min13050647 - 07 May 2023

Cited by 1 | Viewed by 1260

Abstract

Ferromanganese (Fe-Mn) crusts are potential marine deposits for many high-tech metals and are exciting proxies for recording the oceanic paleoenvironment. During their growth, phosphatization generally occurs, causing the remobilization and reorganization of the elements and minerals in Fe-Mn crusts. Rare earth elements plus [...] Read more.

Ferromanganese (Fe-Mn) crusts are potential marine deposits for many high-tech metals and are exciting proxies for recording the oceanic paleoenvironment. During their growth, phosphatization generally occurs, causing the remobilization and reorganization of the elements and minerals in Fe-Mn crusts. Rare earth elements plus yttrium (REY), well-known critical metals for many new and emerging technologies, as well as valuable geological proxies, are the important critical metals in Fe-Mn crusts. The REY occurrence is closely influenced by the phosphatization processes, which still remain discursive. In this study, the textures, structures, and REY geochemistry of the growth of an Fe-Mn crust sample (MP2D32A) from the Line Islands archipelago were analyzed using multiple microanalysis methods. The analyzed Fe-Mn crust is mainly characterized by the presence of laminated and concentric colloforms. Massive fine particles and some veins of carbonate-rich fluorapatite (CFA) were observed in the old part of MP2D32A, demonstrating that this sample underwent phosphatization. The phosphatized and non-phosphatized layers, as well as the CFA veins, display distinctly different PAAS-normalized REY patterns. Higher REY contents in the phosphatized layer than those in the non-phosphatized layer suggest the positive role of phosphatization in REY enrichment. Moreover, the phosphatized layer contains higher REY contents than the CFA, implying that the REY enrichment in the phosphatized layer is not only influenced by CFA and Fe-Mn (oxyhydr)oxides but also other factors, such as the probable PO₄³⁻ complexation induced by Fe oxyhydroxides. The synergistical sorption of REY(III) and HPO₄²⁻ ions on Fe oxyhydroxides should facilitate REY enrichment during the phosphatization processes. These fundamental results provide novel insights into the influence of phosphatization in REY geochemical behaviors in the Fe-Mn crust. Full article

(This article belongs to the Special Issue Critical Metals on Land and in the Ocean)

► Show Figures

Figure 1

19 pages, 9374 KiB

Open AccessArticle

Insights into the Crustal Evolution and Tungsten Mineralization of the West Cathaysia Block: Constraints from the Inherited Zircons from the Mesozoic Dengfuxian and Paleozoic Tanghu Plutons, South China

by Jingya Cao, Youyue Lu, Lei Liu, Jianming Fu, Guofeng Xu, Qianhong Wu, Shengxiong Yang, Xiaofei Qiu and Zunzun Zhang

Minerals 2023, 13(4), 550; https://doi.org/10.3390/min13040550 - 13 Apr 2023

Viewed by 1098

Abstract

The formation and evolution of the ancient continental crust are crucial issues in solid-earth geology which are commonly associated with global tectonic events and the formation of economically valuable magmatic-hydrothermal ore deposits. The Cathaysia Block, one of the ancient continents in Southeast Asia, [...] Read more.

The formation and evolution of the ancient continental crust are crucial issues in solid-earth geology which are commonly associated with global tectonic events and the formation of economically valuable magmatic-hydrothermal ore deposits. The Cathaysia Block, one of the ancient continents in Southeast Asia, can be subdivided into two parts: the West Cathaysia Block and the East Cathaysia Block. Unlike the East Cathaysia Block, no Precambrian rocks are exposed in the West Cathaysia Block, constraining further understanding of the formation and evolution of this block. In this study, a total of four hundred and thirty-three zircon U-Pb dating analyses and two hundred and eighteen Lu-Hf isotopic analyses on zircon grains from the Jurassic Dengfuxian granites and Ordovician Tanghu granites, Nanling Range, were carried out. LA-ICP-MS zircon U-Pb dating yields mean average ²⁰⁶Pb/²³⁸U ages of 152.6 ± 2.2 Ma (MSWD = 1.6) and 442.4 ± 1.7 Ma (MSWD = 3.8), which are regarded as the rock-forming age for the Jurassic Dengfuxian granites and Ordovician Tanghu granites, respectively. The ²⁰⁷Pb/²⁰⁶Pb ages of the inherited zircons from the Jurassic Dengfuxian granites and Ordovician Tanghu granites range from 522 Ma to 3395 Ma, hosting two major peaks at the 0.9–1.0 Ga and 2.4–2.5 Ga. In contrast to the East Cathaysia Block, the West Cathaysia Block lacks the age peak of 1.8–1.9 Ga, indicating that the West Cathaysia Block was not influenced by the assembly of the Columbia supercontinent in the Paleo-Proterozoic. In combination with the Lu-Hf isotopes, we proposed that the crust evolution of the West Cathaysia Block in Archean is dominated by juvenile crustal growth events, and dominated by the crustal reworking since the Proterozoic. The long duration of crustal reworking in the West Cathaysia Block resulted in the enrichment of lithophile elements (e.g., W, Sn, Nb, and Ta) in the crust of that region. Therefore, the Jurassic granites in the Nanling Range, which are mainly derived from the partial melting of Proterozoic basement rocks, became associated with large-scale tungsten polymetallic mineralization. Full article

(This article belongs to the Special Issue Critical Metals on Land and in the Ocean)

► Show Figures

Figure 1

15 pages, 3738 KiB

Open AccessArticle

Controls on Critical Metal Enrichments in Ferromanganese Nodules from the Philippine Sea, at Water Depths of 4400–6000 m

by Chao Li, Weiyu Song, Zhenjun Sun, Gang Hu, Xiaojun Yuan and Shuh-Ji Kao

Minerals 2023, 13(4), 522; https://doi.org/10.3390/min13040522 - 07 Apr 2023

Viewed by 1612

Abstract

Enrichments of critical metals in ferromanganese (Fe–Mn) nodules have received increasing attention in both deep-sea research and mineral exploration. To better assess the controls on the resource potential of Fe–Mn nodules, we conducted a comprehensive and detailed study of twelve nodules from the [...] Read more.

Enrichments of critical metals in ferromanganese (Fe–Mn) nodules have received increasing attention in both deep-sea research and mineral exploration. To better assess the controls on the resource potential of Fe–Mn nodules, we conducted a comprehensive and detailed study of twelve nodules from the Philippine Sea collected from water depths of 4400 to 6000 m by investigating their microstructures, bulk geochemistry, and in situ Fe–Mn oxyhydroxide geochemistry, using XRF, ICP-MS, EMPA, and LA-ICP-MS coupled with BSE images. We successfully resolved different controls on the element enrichments, of which significant selective enrichment of metal elements in seawater is similar to that of typical hydrogenetic nodules. An enhanced supply of iron hydroxide due to calcite dissolution resulted in a dilution effect on Co, Ni, and Mn but an enrichment effect on rare earth elements plus yttrium (REE + Y) and Fe in nodules near topographic highs close to the carbonate compensation depth. While the supply of diagenetic Mn resulted in a dilution on Co and REE + Y, it resulted in enrichment on Ni, Cu, Li, and Mn on nodules on the seafloor. Moreover, via micro-layer analyses we confirmed the growth rate is a major determinant for the correlations of Co and REE with Fe-oxyhydroxides in these Philippine Sea nodules. Full article

(This article belongs to the Special Issue Critical Metals on Land and in the Ocean)

► Show Figures

Figure 1

23 pages, 12928 KiB

Open AccessArticle

In Situ U—Pb Dating and Trace Element Analysis of Garnet in the Tongshanling Cu Polymetallic Deposit, South China

by Fucheng Tan, Hua Kong, Biao Liu, Qianhong Wu and Shefa Chen

Minerals 2023, 13(2), 187; https://doi.org/10.3390/min13020187 - 27 Jan 2023

Cited by 3 | Viewed by 1791

Abstract

The grossular–andradite garnet is an ideal mineral for indicating the formation age of skarn, which also pretends to constrain skarn processes because of its higher REE (rare earth elements) content. The Tongshanling deposit is a medium-sized reduced skarn Cu–W–Pb–Zn deposit associated with a [...] Read more.

The grossular–andradite garnet is an ideal mineral for indicating the formation age of skarn, which also pretends to constrain skarn processes because of its higher REE (rare earth elements) content. The Tongshanling deposit is a medium-sized reduced skarn Cu–W–Pb–Zn deposit associated with a highly evolved I-type granodiorite intrusion in the Nanling metallogenic belt, South China. Different mineral assemblages, microscopic characteristics, and BSE images distinguish two kinds of garnets in the prograde and retrograde skarn stages. The garnet grains from the prograde skarn stage have a U–Pb isochron age of 165.4 ± 3.8 Ma (MSWD = 0.7) and that from the retrograde skarn stage have a U–Pb isochron age of 159.5 ± 1.7 Ma (MSWD = 1.8), implying that the thermal metamorphism and hydrothermal metasomatism mainly occurred in the middle Upper Jurassic. The total amount of rare earth elements (∑REE+Y) in the garnet gradually decreased and the REE patterns shifted from enriched HREE with Eu negative anomaly to HREE-depleted with Eu positive anomaly. The decreasing U content and increasing Eu anomaly in the retrograde skarn stage indicate a redox environment change from oxidation to reduction. However, garnet from different elevations within the same stage (+90 m, +5 m, −35 m, −200 m, and −400 m) exhibit similar REE patterns, despite weak cooling and significant depressurization processes confirmed by fluid inclusion microthermography. As a result, the REE content and patterns are dominated by the REE species of parent fluids, which are changed over time by symbiotic REE-enriched mineral precipitation and the redox environment, while being slightly affected by the fluid pressure. Grossular garnets, rich in U and REEs, and found in reduced skarn deposits, can constrain chronology and reveal the spatio-temporal zonal characteristics. Full article

(This article belongs to the Special Issue Critical Metals on Land and in the Ocean)

► Show Figures

Figure 1

20 pages, 7546 KiB

Open AccessArticle

Metal Source and Fluid Evolution in Xiaojiashan Gold Deposit in Northeastern Hunan, China: Implications of Rare Earth Elements, Fluid Inclusions, and Pyrite S Isotopic Compositions

by Dongzhuang Hou, Shu Lin, Lang Liu, Chao Huan, Huafu Qiu and Bingbing Tu

Minerals 2023, 13(1), 121; https://doi.org/10.3390/min13010121 - 13 Jan 2023

Viewed by 1499

Abstract

The material source and the evolution of ore-forming hydrothermal fluids of Xiaojiashan gold deposits remain controversial. We carried out a mineralogical characteristics analysis, trace elements analysis, sulfur isotope composition analysis, and fluid inclusion microthermometry in order to explore the ore-forming sources, conditions, and [...] Read more.

The material source and the evolution of ore-forming hydrothermal fluids of Xiaojiashan gold deposits remain controversial. We carried out a mineralogical characteristics analysis, trace elements analysis, sulfur isotope composition analysis, and fluid inclusion microthermometry in order to explore the ore-forming sources, conditions, and process of this deposit. Gold mineralization can be divided into three stages: the quartz-pyrite stage, the quartz-polymetallic sulfide stage, and the quartz-ankerite stage. This gold deposit was probably formed under the following conditions: temperature of 122–343 °C and salinity of 0.8–11.4 wt% (NaCl). It was inferred that the ore-forming hydrothermal fluids were early metamorphic–hydrothermal (Stage I) and late magmatic–hydrothermal (Stages II and III), and were characterized by medium–low temperature and medium–low salinity based on fluid inclusion microthermometry and S isotope composition. The temperature and salinity of the ore-forming fluid decreased during mineralization, which was caused by the involvement of groundwater. The chondrite-normalized trace element patterns of the gold ores are similar to the host rocks of the Lengjiaxi Formation, indicating that the ore-forming materials were sourced from the Lengjiaxi Formation. The S isotopes indicated that the magmatic components also provided the ore-forming materials during Stages II and III. Full article

(This article belongs to the Special Issue Critical Metals on Land and in the Ocean)

► Show Figures

Figure 1

19 pages, 16357 KiB

Open AccessArticle

Material Source and Genesis of the Daocaowan Sb Deposit in the Xikuangshan Ore Field: LA-ICP-MS Trace Elements and Sulfur Isotope Evidence from Stibnite

by Xiangfa Song, Jianqing Lai, Junwei Xu, Xianghua Liu, Bin Li, Hongsheng He, Yuhua Wang, Jian Shi, Chaofei Wang and Chunhua Wen

Minerals 2022, 12(11), 1407; https://doi.org/10.3390/min12111407 - 03 Nov 2022

Cited by 4 | Viewed by 1592

Abstract

The Daocaowan antimony (Sb) deposit is a newly discovered Sb deposit located outside the northeast Xikuangshan ore field. In the absence of geochemical data, the metallogenic mechanism of the Daocaowan Sb deposit and its relationship with the Xikuangshan ore field remains unclear. Using [...] Read more.

The Daocaowan antimony (Sb) deposit is a newly discovered Sb deposit located outside the northeast Xikuangshan ore field. In the absence of geochemical data, the metallogenic mechanism of the Daocaowan Sb deposit and its relationship with the Xikuangshan ore field remains unclear. Using high-resolution LA-ICP-MS technique, this study quantitatively determined the in-situ S isotope values and trace element composition of stibnite from the Daocaowan Sb deposit in South China to investigate the source of ore-forming materials and genesis of this deposit. The trace element compositions of stibnite from the Daocaowan Sb deposit revealed the form of occurrence and substitution mechanism of trace elements in stibnite, providing new constraints for explaining the genesis of Sb deposits. The relatively smooth LA-ICP-MS profiles indicate that As, Cu, Hg, and Pb primarily occur as solid solutions in stibnite. Therefore, we speculate that the substitution 3Sb³⁺↔As³⁺ + 2Cu⁺ + Hg²⁺ + Pb²⁺ may be the reason for the enrichment of As, Cu, Hg, and Pb in stibnite. A comparison with the Xikuangshan Sb deposit reveals the metallogenic mechanism of the Daocaowan Sb deposit, and the relationship between the two. With the exception of higher content of Fe in Stibnite from the Daocaowan deposit as compared to the Xikuangshan deposit, other trace elements are similar between the two deposits. The results show that the Daocaowan and Xikuangshan Sb deposits may have the same source of ore-forming fluids. We propose that the ore-forming fluid flowed through the Xikuangshan Sb deposit along the F₇₅ fault and dissolved pyrite in the wall rock. Subsequently this fluid containing a high concentration of Fe precipitated and mineralized at Daocaowan. Meanwhile, the S isotope value of the Daocaowan Sb deposit (+6.65 to +9.29‰) is consistent with that of the Xikuangshan, proving that the ore-forming materials of the two deposits are from the same source, probably the basement strata. We propose that the Daocaowan Sb deposit is part of the Xikuangshan ore field, indicating a great prospecting potential in the northeast of the Xikuangshan ore field. Full article

(This article belongs to the Special Issue Critical Metals on Land and in the Ocean)

► Show Figures

Figure 1

24 pages, 6673 KiB

Open AccessArticle

Partial Least Squares-Discriminant Analysis of the Major and Trace Elements and their Evolutionary Characteristics from the Jinchuan Ni-Cu-(PGE) Sulfide Deposit, NW China

by Yuhua Wang, Jianqing Lai, Yonghua Cao, Xiancheng Mao, Xianghua Liu, Lu Peng and Qixing Ai

Minerals 2022, 12(10), 1301; https://doi.org/10.3390/min12101301 - 16 Oct 2022

Cited by 4 | Viewed by 1728

Abstract

The world-renowned Jinchuan Cu-Ni-(PGE) sulfide deposit consists of four mainly independent intrusive units from west to east, namely Segments III, I, II-W, and II-E, and the main sulfide types are the disseminated, net-textured, massive, and Cu-rich ores. Due to the similar geochemical characteristics [...] Read more.

The world-renowned Jinchuan Cu-Ni-(PGE) sulfide deposit consists of four mainly independent intrusive units from west to east, namely Segments III, I, II-W, and II-E, and the main sulfide types are the disseminated, net-textured, massive, and Cu-rich ores. Due to the similar geochemical characteristics of each segment, there is no convenient method to distinguish them and explain their respective variations. Meanwhile, considering that the division of different types of ores is confusing and their formation is still controversial, direct classification using elemental discrimination maps can facilitate subsequent mining and research. In this paper, we report the new major and trace elements data from the Jinchuan deposit and collect the published data to construct a database of 10 major elements for 434 samples and 33 trace elements for 370 samples, respectively, and analyze the data based on multivariate statistical analysis for the first time. Robust estimation of compositional data (robCompositions) was applied to investigate censored geochemical data, and the input censored data were transformed using the centered log-ratios (clr) to overcome the closure effect on compositional data. Exploratory data analysis (EDA) was used to characterize the spatial distribution and internal structural features of the data. The transformed data were classified by partial least squares-discriminant analysis (PLS-DA) to identify different compositional features for each segment and ore type. The receiver operator characteristic (ROC) curve was used to verify the model results, which showed that the PLS-DA model we constructed was reliable. The main discriminant elements were obtained by PLS-DA of the major and trace elements, and based on these elements, we propose the plot of SiO₂ + Al₂O₃ vs. CaO + Na₂O + K₂O and Cs + Ce vs. Th + U to discriminate the different segments of the Jinchuan deposit, and the Al₂O₃ + CaO vs. Fe₂O₃^T + Na₂O and Co + Cu vs. Rb + Th + U to discriminate the different ore types. In addition, we predict that there are still considerable metal reserves at the bottom of Segment I. Full article

(This article belongs to the Special Issue Critical Metals on Land and in the Ocean)

► Show Figures

Figure 1

21 pages, 5898 KiB

Open AccessArticle

Origin and Geodynamic Mechanism of the Tibetan Demingding Porphyry Mo (Cu) Deposit from Oceanic Subduction to Continental Collision

by Yigan Lu, Kai Dong, Hui Zhou and Zhuoyang Li

Minerals 2022, 12(10), 1266; https://doi.org/10.3390/min12101266 - 08 Oct 2022

Cited by 2 | Viewed by 1420

Abstract

Demingding is a promising porphyry Mo-dominated deposit recently discovered in the eastern Gangdese metallogenic belt in Tibet, China. We present zircon U-Pb-Lu-Hf isotopic studies, as well as geochemical data of the late monzogranites and the prior rhyolites from the Demingding porphyry deposit to [...] Read more.

Demingding is a promising porphyry Mo-dominated deposit recently discovered in the eastern Gangdese metallogenic belt in Tibet, China. We present zircon U-Pb-Lu-Hf isotopic studies, as well as geochemical data of the late monzogranites and the prior rhyolites from the Demingding porphyry deposit to uncover their origin and geodynamic mechanism. Zircon U–Pb dating yielded precise crystallization ages of 17.3 ± 0.6 Ma (MSWD = 2.5) and 186.5 ± 3.0 Ma (MSWD = 2.0) for monzogranite and rhyolite, respectively. The monzogranite is characterized by high-K calc-alkaline, adakitic affinities, and positive zircon ε_Hf(t) values (+0.9∼+5.6, avg.+3.1) with T_DM2 (0.73–1.04 Ga), while the rhyolite has ε_Hf(t) values of (+2.1∼+7.3, avg.+5.2) and T_DM2 of (0.76–1.09 Ga) similar to the monzogranite. Our results suggest that the Demingding porphyry Mo (Cu) deposit is related to magma generated from the Neo-Tethyan oceanic subduction. The subsequent monzogranite porphyry was likely formed by the remelting of previously subduction-modified arc lithosphere, triggered by continental collision crustal thickening in Miocene. The lower positive ε_Hf(t) values of monzogranites suggest minor inputs from the Mo-rich ancient crust, suggesting that Mo favors the silicate melt. Such magmatic events and special metallogenesis typify intracontinental processes and porphyry copper deposits, which are normally confined to oceanic subduction and Cu-dominated style, thereby making the continental setting and Mo-dominated style of Demingding exceptional and possibly unique. Full article

(This article belongs to the Special Issue Critical Metals on Land and in the Ocean)

► Show Figures

Figure 1

32 pages, 18313 KiB

Open AccessArticle

In Situ Monazite U–Pb Ages in Thin Sections from the Giant Bayan Obo Fe–REE–Nb Deposit, Inner Mongolia: Implications for Formation Sequences

by Pengfei Tian, Xiaoyong Yang, Yulun Xiao, Wanming Yuan and Zifei He

Minerals 2022, 12(10), 1237; https://doi.org/10.3390/min12101237 - 28 Sep 2022

Cited by 1 | Viewed by 2003

Abstract

The Bayan Obo deposit is the largest REE resource in the world. Although many isotopic dating methods have been applied, ages based on petrography and closure temperatures still lack discussion. In this study, three digital petrographic images were created based on full-scanning microscopy, [...] Read more.

The Bayan Obo deposit is the largest REE resource in the world. Although many isotopic dating methods have been applied, ages based on petrography and closure temperatures still lack discussion. In this study, three digital petrographic images were created based on full-scanning microscopy, BSE, and TESCAN integrated mineral analysis (TIMA), providing a more scientific method for analyzing the mineral types, distributions, and content of the Bayan Obo deposit. By combining the full-scan images, monazites were selected in thin sections and dated in situ. The monazite in the body ores sample yields three ²⁰⁷Pb intercept ages of 657 ± 25 Ma (MSWD = 1.06), 763 ± 16 Ma (MSWD = 1.3), and 689 ± 22 Ma (MSWD = 8.1), and the monazite in one section yields maximum and minimum ages of 1393 ± 142 Ma and 429 ± 24 Ma, respectively. Combined with previous studies, the earliest and major stages of carbonatites, REE, and dikes in the Bayan Obo deposit area were dated at ~1.4 Ga and ~1.3 Ga, respectively. Due to the multiple subduction and accretion events related to the Paleo-Asian Ocean and North China Craton, the Bayan Obo deposit is intensely overprinted, with a tectonic-thermal event recorded at ~1.0–0.2 Ga. The multiple or protracted isotopic ~1.4–0.4 Ga ages in the Bayan Obo deposit account for five reasons. First, the separate thermal events and the partial recrystallization of monazite. Second, the diffusion of daughter products from the host mineral over time. Third, differences in the closure temperatures of different minerals and isotopic chronologies. Four, resetting of the closure system due to high temperature and hydrothermal alteration. Five, the minerals and transformed ores that formed in the Paleozoic. The in situ monazite U–Pb ages in thin sections provide insight into formation sequences from the giant Bayan Obo Fe–REE–Nb deposit. Full article

(This article belongs to the Special Issue Critical Metals on Land and in the Ocean)

► Show Figures

Figure 1

Review

Jump to: Research

22 pages, 39333 KiB

Open AccessReview

Ni(Co) Laterite Deposits of Southeast Asia: A Review and Perspective

by Landry Soh Tamehe, Yanpeng Zhao, Wenjie Xu and Jiahao Gao

Minerals 2024, 14(2), 134; https://doi.org/10.3390/min14020134 - 26 Jan 2024

Viewed by 1684

Abstract

Southeast Asia has great potential for mineral exploration, and this region is well-known to host huge economic ore deposits located in complex tectonic terranes. Amongst these ore deposits, the Ni(Co) laterite deposits are mainly distributed in Indonesia, the Philippines, and Myanmar. There are [...] Read more.

Southeast Asia has great potential for mineral exploration, and this region is well-known to host huge economic ore deposits located in complex tectonic terranes. Amongst these ore deposits, the Ni(Co) laterite deposits are mainly distributed in Indonesia, the Philippines, and Myanmar. There are two main types of Ni(Co) laterite deposits consisting of hydrous Mg silicate (or garnierite) and oxide ores, with limited development of clay silicate type. These deposits are influenced and controlled by the lithology of ultramafic bedrock, topography, climate, weathering, structures, and tectonic environment. The degree of bedrock serpentinization has an important influence on the grade of Ni laterite ore. Given the growing demand of modern society for Ni(Co) ore resources, deep research should be focused on a better understanding of the genesis of this laterite deposit and geological features of Ni(Co) ore, as well as its exploration applications in southeastern Asia. Improving current research and exploration methods by means of cutting-edge technologies can enhance the understanding of the Ni(Co) enrichment mechanism in weathered laterite and lead to the discovery of new deposits in Southeast Asia. Ni(Co) laterite deposits from this region, especially Indonesia and the Philippines, have the potential to be a source of scandium, rare earth elements, and platinum group elements. Full article

(This article belongs to the Special Issue Critical Metals on Land and in the Ocean)

► Show Figures

Figure 1

Journal Menu

Journal Browser

Critical Metals on Land and in the Ocean

Share This Special Issue

Special Issue Editors

Special Issue Information

Keywords

Published Papers (12 papers)

Research

Review

Further Information

Guidelines

MDPI Initiatives

Follow MDPI