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21 pages, 11239 KiB

Open AccessArticle

Genetic Model of the Luhai Sandstone-Type Uranium Deposit in the Erlian Basin, Inner Mongolia

by Chao Tang, Zenglian Xu, Ming Duan, Lishan Meng, Huajian Liu, Jialin Wei, Chao Zhang and Lijun Zhao

Minerals 2025, 15(3), 294; https://doi.org/10.3390/min15030294 - 13 Mar 2025

Abstract

The Luhai uranium deposit is a large-scale uranium deposit newly discovered in recent years through comprehensive prospecting methods. It is located in the Basaiqi Paleochannel Uranium metallogenic belt of the Erlian Basin and is characterized by its shallow burial and large scale. This [...] Read more.

The Luhai uranium deposit is a large-scale uranium deposit newly discovered in recent years through comprehensive prospecting methods. It is located in the Basaiqi Paleochannel Uranium metallogenic belt of the Erlian Basin and is characterized by its shallow burial and large scale. This paper provides new data on the genetic processes of sandstone-type uranium mineralization through sedimentological and geochemical environmental indicators (such as Fe³⁺/Fe²⁺, organic carbon, total sulfur, etc.), analysis of C-O isotopes of carbonate cements and H-O isotopes of groundwater, and geochemical and mineralogical studies of uranium minerals, iron–titanium oxides (involving backscatter analysis, micro-area chemical composition determination, and elemental surface scanning), and organic matter. Sedimentological analysis shows that the ore- bearing layer in the upper member of the Saihan Formation developed a braided channel within floodplain subfacies, which control the distribution of uranium ore bodies. Uranium mineralogical observations, geochemical environmental indicators, and organic geochemical data indicate that the main reducing agents related to mineralization are pyrite, terrestrial plants, and deep-sourced oil and gas. The δD values of groundwater in the ore-bearing layer range from −95.34‰ to −90.68‰, and the δ¹⁸O values range from −12.24‰ to −11.87‰. For calcite cements, the δ¹⁸O_V-PDB values range from −24‰ to −11.5‰, and the δ¹⁸_OV-SMOW values range from 6.2‰ to 19‰. It was determined that the ore-forming fluid is mainly surface fresh water that entered the strata during the tectonic uplift stage, with local mixing of deep-sourced brine. Based on these data, the main modes of uranium mineralization in the paleochannel were obtained as follows: (1) Redox mineralization occurs due to the reducing medium within the sand body itself and the reduction caused by deep- sourced oil and gas generated from the Tengge’er and Arshan Formations. (2) Mineralization is achieved through the mixing of fluids from different sources. Furthermore, a genetic model related to uranium mineralization in the paleochannels of the Luhai area has been established: favorable uranium reservoirs were formed during the sedimentary period, and during the post-sedimentary stage, reverse structures promoted redox reactions and fluid-mixing-induced mineralization. The research findings can provide guidance for the exploration of paleochannel sandstone-type uranium deposits in other areas of the Erlian Basin. Full article

(This article belongs to the Special Issue Genesis and Metallogeny of Non-ferrous and Precious Metal Deposits, 2nd Edition)

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16 pages, 11787 KiB

Open AccessArticle

Genesis of the Xiangluwanzi Gold Deposit, Northeastern China: Insights from Fluid Inclusions and C-H-O Isotopes

by He Yang, Keyong Wang and Bingyang Ye

Minerals 2025, 15(3), 250; https://doi.org/10.3390/min15030250 - 28 Feb 2025

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Abstract

The Xiangluwanzi gold deposit, located in the southern Jilin Province of Northeast China, is hosted within the Jurassic Guosong Formation, and surrounded by Archean granitoids. The ore bodies are governed by near-EW and NE-trending faults. Four alteration/mineralization stages have been distinguished: I, pyrite–sericite–quartz; [...] Read more.

The Xiangluwanzi gold deposit, located in the southern Jilin Province of Northeast China, is hosted within the Jurassic Guosong Formation, and surrounded by Archean granitoids. The ore bodies are governed by near-EW and NE-trending faults. Four alteration/mineralization stages have been distinguished: I, pyrite–sericite–quartz; II, gold–pyrite–quartz; III, sphalerite–quartz–carbonate; and IV, quartz–carbonate. Four types of fluid inclusions (FIs) were identified: pure CO₂, CO₂-rich, CO₂-bearing, and NaCl–H₂O fluid inclusions. Stage-I quartz veins contain all FIs, whereas stage II quartz veins host CO₂-rich, CO₂-bearing, and NaCl-H₂O FIs. Only NaCl–H₂O FIs were present in stages-III and -IV quartz veins. The homogenization temperatures of the FIs range, respectively, from 233 to 279, 185–242, 171–217, and 148–170 °C in stages I–IV, having salinities of 2.62–8.54, 2.81–7.58, 4.32–6.58, and 3.37–5.25 wt% NaCl equivalents, respectively. The H (−93.5‰ to −75.9‰) and O (^δ18O_H2O = −5.8‰ to 4.6‰) isotopic compositions suggest magmatic water was gradually diluted by meteoric water. Carbon isotopic values (22.8‰ to −17.8‰) suggest the incorporation of organic carbon from surrounding strata via water–rock interactions. Fluid boiling, fluid mixing, and water–rock interactions are the primary mechanisms driving mineral precipitation. Full article

(This article belongs to the Special Issue Genesis and Metallogeny of Non-ferrous and Precious Metal Deposits, 2nd Edition)

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15 pages, 4699 KiB

Open AccessArticle

Deep Exploration Porphyry Molybdenum Deposit in Dasuji, Inner Mongolia: Insight from Aeromagnetism and Controlled-Source Audio-Magnetotellurics

by Zhihe Xu, Xingguo Niu, Bin Shi, Zhongjie Yang, Haoyuan He, Weijing Fan, Guanwen Gu, Yingjie Wang and Ningning Yang

Minerals 2025, 15(2), 166; https://doi.org/10.3390/min15020166 - 11 Feb 2025

Viewed by 424

Abstract

Porphyry molybdenum deposits hold significant potential for deep exploration. However, in the Dasuji molybdenum deposit, quartz porphyry, granite porphyry, and syenogranite are sporadically exposed beneath low mountains and hilly terrain, limiting the effectiveness of traditional geological methods. Consequently, geophysical techniques have become essential [...] Read more.

Porphyry molybdenum deposits hold significant potential for deep exploration. However, in the Dasuji molybdenum deposit, quartz porphyry, granite porphyry, and syenogranite are sporadically exposed beneath low mountains and hilly terrain, limiting the effectiveness of traditional geological methods. Consequently, geophysical techniques have become essential in this region. This study provides new magnetism and resistivity data obtained through high-precision aeromagnetic surveys and controlled-source audio-magnetotellurics (CSAMT) profiles. These results reveal concealed deep porphyries, identify deep-seated molybdenum ore bodies, and establish a porphyry-type molybdenum metallogenic model. The porphyries exhibit the lowest magnetic values (about −200 to 370 nT), suggesting that molybdenum mineralization-related granitoids have exceeded the Curie temperature and undergone an intense magnetic weakening effect. Ferromagnetic or ferromagnetic substances have transformed into paramagnetic substances. The CSAMT results indicate that the mineralized granite porphyry generally has medium to high resistivity (300 Ω·m to 500 Ω·m) and dips southward with a 60° inclination angle. Additionally, an unclosed low-resistance anomaly in the deep region of site 0 indicates promising potential for further mineral exploration and the discovery of deeper mineralized porphyries. We interpret weak magnetic anomalies and variations in resistivity as caused by high crystallization temperatures, low oxygen fugacity, and hydrothermal alteration in the context of porphyry molybdenum deposit mineralization. Full article

(This article belongs to the Special Issue Genesis and Metallogeny of Non-ferrous and Precious Metal Deposits, 2nd Edition)

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35 pages, 18372 KiB

Open AccessArticle

The Initial Subduction Time of the Proto-Tethys Ocean in the Eastern Section of the East Kunlun Orogen: The Constraints from the Zircon U-Pb Ages and the Geochemistry of the Kekesha Intrusion

by Jian Song, Xianzhi Pei, Zuochen Li, Ruibao Li, Lei Pei, Youxin Chen and Chengjun Liu

Minerals 2025, 15(2), 127; https://doi.org/10.3390/min15020127 - 27 Jan 2025

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Abstract

The Cambrian period marks a crucial phase in the initial subduction of the Proto-Tethys Ocean beneath the East Kunlun Orogen. Studying the I-type granites and mafic–ultramafic rocks formed during this period can provide valuable insights into the early Paleozoic tectonic evolution of the [...] Read more.

The Cambrian period marks a crucial phase in the initial subduction of the Proto-Tethys Ocean beneath the East Kunlun Orogen. Studying the I-type granites and mafic–ultramafic rocks formed during this period can provide valuable insights into the early Paleozoic tectonic evolution of the region. This paper incorporates petrology, LA-ICP-MS zircon U-Pb geochronology, and whole-rock major and trace element data obtained from the Kekesha intrusion in the eastern section of the East Kunlun Orogen. The formation age, petrogenesis, and magmatic source region of the intrusion are revealed, and the early tectonic evolution process of the subduction of the Proto-Tethys Ocean is discussed. The Kekesha intrusion includes four main rock types: gabbro, gabbro diorite, quartz diorite, and granodiorite. The zircon U-Pb ages are 515.7 ± 7.4 Ma for gabbro, 508.9 ± 9.8 Ma for gabbro diorite, 499.6 ± 4.0 Ma for quartz diorite, and 502.3 ± 9.3 Ma and 501.6 ± 6.2 Ma for granodiorite, respectively, indicating that they were formed in the Middle Cambrian. The geochemical results indicate that the gabbro belongs to the high-Al calc-alkaline basalt series, the gabbro diorite belongs to the medium-high-K calc-alkaline basalt series, the quartz diorite belongs to the quasi-aluminous medium-high-K calc-alkaline I-type granite series, and the granodiorite belongs to the weakly peraluminous calc-alkaline I-type granite series, all of which belong to the medium-high-K calc-alkaline series that have undergone varying degrees of differentiation and contamination. Gabbro and gabbro diorite exhibit significant enrichment in light rare earth elements (LREEs), depletion in heavy rare earth elements (HREEs), and an enhanced negative anomaly in Eu (Europium). Compared to gabbro and gabbro diorite, quartz diorite and granodiorite exhibit more pronounced enrichment in LREEs, more significant depletion in HREEs, and an enhanced negative anomaly in Eu. All four rock types are enriched in large-ion lithophile elements (LILEs) such as Cs, Rb, Th, Ba, and U, and are depleted in high-field-strength elements (HFSEs) such as Nb, Ta, and Ti. This indicates that these rocks originated from the same or similar mixed mantle source regions, and that they are formed in the island-arc tectonic environment. This paper suggests that the gabbro and gabbro diorite are mainly derived from the basic magma formed by partial melting of the lithospheric mantle metasomatized by subducted slab melt in the oceanic crust subduction zone and mixed with a small amount of asthenosphere mantle material. Quartz diorite results from the crystal fractionation of basic magma and experiences crustal contamination during magmatic evolution. Granodiorite forms through the crystal fractionation of basic magma, mixed with partial melting products from quartz diorite. While the lithology of the intrusions differs, their geochemical characteristics suggest they share the same tectonic environment. Together, they record the geological processes associated with island-arc formation in the East Kunlun region, driven by the northward subduction of the Proto-Tethys Ocean during the Early Paleozoic. Based on regional tectonic evolution, it is proposed that the Proto-Tethys Ocean began subducting northward beneath the East Kunlun block from the Middle Cambrian. The Kekesha intrusion formed between 516 and 500 Ma, marking the early stages of Proto-Tethys Ocean crust subduction. Full article

(This article belongs to the Special Issue Genesis and Metallogeny of Non-ferrous and Precious Metal Deposits, 2nd Edition)

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26 pages, 15286 KiB

Open AccessArticle

Late Triassic Felsic and Mafic Magmatism in the South Qinling Orogen, Central China: Insights from the Petrology, Zircon U-Pb Geochronology, and Geochemistry of the Huoshaodian Pluton

by Meijing Li, Xianzhi Pei, Lei Pei, Zuochen Li, Ruibao Li, Shaowei Zhao, Li Qin, Mao Wang and Xiao Wang

Minerals 2025, 15(2), 120; https://doi.org/10.3390/min15020120 - 26 Jan 2025

Viewed by 599

Abstract

The petrology, geochemistry, and zircon U-Pb chronology of the Huoshaodian pluton in the Liuba area of the western part of the South Qinling tectonic belt are investigated in this study. The Huoshaodian pluton consists of gabbro, quartz diorite, and granodiorite, and the dominated [...] Read more.

The petrology, geochemistry, and zircon U-Pb chronology of the Huoshaodian pluton in the Liuba area of the western part of the South Qinling tectonic belt are investigated in this study. The Huoshaodian pluton consists of gabbro, quartz diorite, and granodiorite, and the dominated rock type is quartz diorite. The results indicate that the Huoshaodian pluton belongs to the calc-alkaline series. In the chondrite-normalized REE, all of the samples showed similar patterns, with an enrichment of light REEs and depletion of heavy REEs, but they showed slight differences in the degrees of Eu anomalies. The primitive mantle-normalized trace element diagram reveals an enrichment of large-ion lithophile elements (LILEs) and light rare earth elements (LREEs), as well as depleted high field strength elements (HFSEs). The zircon U-Pb dating results reveal that the gabbro, quartz diorite, and granodiorite have crystallization ages of 214.9 ± 0.58 Ma, 215.0 ± 1.2 Ma, and 215.4 ± 1.9 Ma, respectively, indicating that the Huoshaodian pluton was emplaced during the late Triassic period (214.9–215.4 Ma). In terms of petrogenesis, the gabbro of the Huoshaodian pluton originates from a transitional lithospheric mantle that has undergone fluid metasomatism and partial melting. Specifically, it originated through 1%–2% garnet spinel peridotite undergoing partial melting. In addition, the gabbro underwent a slight degree of contamination by crustal materials during its ascent and intrusion, with some continental crust material being incorporated. The quartz diorite and granodiorite of the Huoshaodian pluton are formed through partial melting processes occurring within the normal lower crust. Combined with the previous studies on the early Mesozoic tectonic evolution of the South Qinling, this study proposes that the formation mechanism of the Huoshaodian pluton may be as follows: in the early Triassic, the Mianlue Ocean subducted northward beneath the Qinling microblock, resulting in a large-scale continental-continental collision between the North China Block and the Yangtze Block; when the oceanic crust subducted to a certain depth, the detachment of the subducting slab triggered the upwelling of mantle material. The heat from mantle-derived magma caused the partial melting of the mafic lower crust, while the mafic magma entered into the upper granitic magma chamber and began to mix. Due to the high viscosity contrast and temperature difference between the two end-member magmas, incomplete mixing led to the formation of a melt with distinct adakitic characteristics and a mafic melt representing mantle-derived material. Full article

(This article belongs to the Special Issue Genesis and Metallogeny of Non-ferrous and Precious Metal Deposits, 2nd Edition)

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25 pages, 8369 KiB

Open AccessArticle

Origin of Diorites and Coeval Mafic Microgranular Enclaves in the Liuba Region, South Qinling Orogen, Central China: Insights from Petrography, Zircon U-Pb Geochronology and Geochemistry

by Shan Gao, Xianzhi Pei, Lei Pei, Zuochen Li, Ruibao Li, Shaowei Zhao, Mao Wang, Li Qin and Xiao Wang

Minerals 2025, 15(1), 77; https://doi.org/10.3390/min15010077 - 15 Jan 2025

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Abstract

The formation of early Mesozoic granitoid plutons in the Qinling Orogen is widely regarded as a result of the collision and accretion between the Yangtze Block and the South Qinling Block during the early Mesozoic, but the specific magmatic process, source composition, tectonic [...] Read more.

The formation of early Mesozoic granitoid plutons in the Qinling Orogen is widely regarded as a result of the collision and accretion between the Yangtze Block and the South Qinling Block during the early Mesozoic, but the specific magmatic process, source composition, tectonic environment and deep dynamic background remain controversial. This study reports the petrology, zircon U–Pb geochronology, and whole-rock geochemistry of diorites from the Liuba and Qingyangyi plutons in the South Qinling, to provide new evidence for understanding the final collision tectonic evolution process of Qinling Orogenic belt. The Liuba and Qingyangyi plutons, located in the central part of the South Qinling region, are primarily composed of quartz diorite and quartz monzodiorite, respectively. The results indicate that the weighted mean crystallization ages of the quartz diorite in the Liuba pluton range from 216.1 ± 0.8 Ma to 217.1 ± 1.3 Ma, with the weighted mean crystallization ages of its MMEs being 215.4 ± 1.0 Ma. The crystallization ages of the quartz monzodiorite in the Qingyangyi pluton range from 214.6 ± 0.9 Ma to 215.4 ± 0.9 Ma, suggesting that both plutons were formed in the late Triassic. The investigated plutons are characterized as right-leaning and have weak negative Eu anomalies on the chondrite-normalized REE patterns diagram. The large ion lithophile elements (LILE) Rb, Ba, Th and K are relatively enriched, while high-field strength elements (HFSE) Nb, Ta, Ti and P are strongly depleted. The formation of numerous MMEs in the Liuba pluton is the product of magmatic mixing. The Liuba and Qingyangyi plutons are the results of crust thickening and partial melting of lower crust caused by the comprehensive late Triassic collision between the Yangtze Block and the North China Block (NCB), and are the manifestation of magmatic intrusion along the South Qinling tectonic belt in the late Triassic period. Full article

(This article belongs to the Special Issue Genesis and Metallogeny of Non-ferrous and Precious Metal Deposits, 2nd Edition)

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26 pages, 20145 KiB

Open AccessArticle

In Situ Compositional and Sulfur Isotopic Analysis of Sphalerite from the Erdaodianzi Gold Deposit in Southern Jilin Province, Northeast China

by Qingqing Shang, Fengdi Ren, Qun Yang and Bin Wang

Minerals 2025, 15(1), 57; https://doi.org/10.3390/min15010057 - 7 Jan 2025

Viewed by 525

Abstract

The newly discovered Erdaodianzi gold deposit in southern Jilin Province, Northeast China, is located in the eastern segment of the northern margin of the North China Craton (NCC). It is a large-scale gold deposit with reserves of 38.4 tons of gold. Gold mineralization [...] Read more.

The newly discovered Erdaodianzi gold deposit in southern Jilin Province, Northeast China, is located in the eastern segment of the northern margin of the North China Craton (NCC). It is a large-scale gold deposit with reserves of 38.4 tons of gold. Gold mineralization in the ore district primarily occurs in gold-bearing quartz–sulfide veins. The gold ore occurs mainly as vein, veinlet, crumby, and disseminated structures. The hydrothermal process can be divided into three stages: stage I, characterized by quartz, arsenopyrite, and pyrite; stage II, featuring quartz, arsenopyrite, pyrite, pyrrhotite, chalcopyrite, sphalerite, and native gold; and stage III, consisting of quartz, pyrite, sphalerite, galena, electrum (a naturally occurring Au–Ag alloy), and calcite. Electrum and native gold primarily occur within the fissures of the polymetallic sulfides. To determine the enrichment mechanism of the Au element and the genetic types of ore deposits in the Erdaodianzi deposit, sourcing in situ trace element data, element mapping and sulfur isotope analysis were carried out on sphalerites from different stages using LA-ICP-MS. Minor invisible gold, in the form of Au–Ag alloy inclusions, is present within sphalerites, as revealed by time-resolved depth profiles. The LA-ICP-MS trace element data and mapping results indicate that trivalent or quadrivalent cations, such as Sb³⁺ and Te⁴⁺, exhibit a strong correlation with Au. This correlation can be explained by a coupled substitution mechanism, where these cations (Sb³⁺ and Te⁴⁺) replace zinc ions within the mineral structure, resulting in a strong association with Au. Similarly, the element Pb exhibits a close relationship with Au, which can be attributed to the incorporation of tetravalent cations like Te⁴⁺ into the mineral structure. The positive correlation between Hg and Au can be attributed to the formation of vacancies and defects within sphalerite, caused by the aforementioned coupled substitution mechanism. A slight positive relationship between Au and other divalent cations, including Fe²⁺, Mn²⁺, and Cd²⁺, may result from these cations simply replacing Zn within the sphalerite lattice. The crystallization temperatures of the sphalerite, calculated via the Fe/Zn ratio, range from 238 °C to 320 °C. The δ³⁴S values are divided into two intervals: one ranging from −1.99 to −1.12‰ and the other varying from 10.96 to 11.48‰. The sulfur isotopic analysis revealed that the ore-forming materials originated from magmatic rock, with some incorporation of metamorphic rock. Comparative studies of the Erdaodianzi gold deposit and other gold deposits in the Jiapigou–Haigou gold belt have confirmed that they are all mesothermal magmatic–hydrothermal lode gold deposits formed at the subduction of the Paleo-Pacific Plate beneath the Eurasian Plate during the Middle Jurassic. The Jiapigou–Haigou gold belt extends northwest to the Huadian area of Jilin province. This suggests potential for research on gold mineralization in the northwest of the belt and indicates a new direction for further gold prospecting in the region. Full article

(This article belongs to the Special Issue Genesis and Metallogeny of Non-ferrous and Precious Metal Deposits, 2nd Edition)

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26 pages, 9981 KiB

Open AccessArticle

Ore Formation and Mineralogy of the Alattu–Päkylä Gold Occurrence, Ladoga Karelia, Russia

by Vasily I. Ivashchenko

Minerals 2024, 14(11), 1172; https://doi.org/10.3390/min14111172 - 18 Nov 2024

Viewed by 759

Abstract

The Alattu–Päkylä gold occurrence is located in the Northern Lake Ladoga area, in the Raaha-Ladoga suprasubduction zone, at the Karelian Craton (AR)—Svecofennian foldbelt (PR₁) boundary. Its gold ore mineral associations are of two types of mineralization: (1) copper–molybdenum–porphyry with arsenopyrite and [...] Read more.

The Alattu–Päkylä gold occurrence is located in the Northern Lake Ladoga area, in the Raaha-Ladoga suprasubduction zone, at the Karelian Craton (AR)—Svecofennian foldbelt (PR₁) boundary. Its gold ore mineral associations are of two types of mineralization: (1) copper–molybdenum–porphyry with arsenopyrite and gold (intrusion-related) and (2) gold–arsenopyrite–sulfide in shear zones. Optical and scanning electron microscopy, X-ray fluorescence spectrometry, inductively coupled plasma mass spectrometry (ICP-MS), instrumental neutron activation analysis (INAA) and fire analysis with AAS finishing were used to study them. Type 1 was provoked by shallow-depth tonalite intrusion (~1.89 Ga) and type 2 by two stages of Svecofennian metamorphism (1.89–1.86 and 1.83–1.79 Ga) with the possible influence of the impactogenesis of the Janisjärvi astrobleme (age ~1 Ga). Intrusive and host rocks were subjected to shearing accompanied by the formation of ore-bearing metasomatic rocks of the propylite-beresite series (depending on substrate) and quartz–sericite, quartz and sericite–tourmaline veins and streaks. Ore mineralization is present as several consecutive mineral associations: pyritic–molybdenite with arsenopyrite and gold; gold–arsenopyrite; quartz–arsenopyrite with antimony sulfosalts of lead; gold–polysulfide with tetrahedrite –argentotetrahedrite series minerals and gold–antimony with Pb–Sb–S system minerals and native antimony. Arsenopyrite contains invisible (up to 234 ppm) and visible gold. Metamorphosed domains in arsenopyrite and rims with visible gold around it are usually enriched in As, indicating higher (up to >500 °C) temperatures of formations than original arsenopyrite with invisible gold (<500 °C). A paragenetic sequence associated with the deposition of invisible and visible gold established at the Alattu–Päkylä ore occurrence: pyrrhotite + unaltered arsenopyrite (with invisible gold) → altered arsenopyrite (As-enriched) + pyrite ± pyrrhotite + visible gold. Gold, associated with gudmundite, sphalerite and native antimony, seems to be due to cainotypic rhyodacitic porphyry cutting tonalite intrusion or with a retrograde stage in post-Svecofennian metamorphism. The isotopic composition of Pb and ²³⁸U/²⁰⁴Pb (9.4–9.75) for the feldspar of the tonalite intrusion and the pyrite of gold mineralization, εNd (−4 up to −5) for tonalites and ẟ³⁴S values of −2.10–+4.99 for arsenopyrite, indicate the formation of gold occurrence provoked by Svecofennian magmatic and tectono-thermal processes with the involvement of matter from a mantle-lower crustal reservoir into magma formation and mineralization. Full article

(This article belongs to the Special Issue Genesis and Metallogeny of Non-ferrous and Precious Metal Deposits, 2nd Edition)

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19 pages, 10283 KiB

Open AccessArticle

Genesis and Tectonic Implications of Early Cretaceous Granites in the Haobugao Area, Southern Great Xing’an Range: Insights from Zircon U–Pb Geochronology, Hf Isotopic Composition, and Petrochemistry

by Mengling Li, Henan Yu, Yi Tian, Haixin Yue, Yanping He, Yingbo Yu and Zhenjun Sun

Minerals 2024, 14(11), 1139; https://doi.org/10.3390/min14111139 - 11 Nov 2024

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Abstract

In the Huanggangliang–Ganzhuermiao metallogenic belt in the southern Great Xing’an Range, the Haobugao Pb–Zn deposit is the most widespread skarn-type polymetallic deposit. The observed mineralization processes in this area are closely associated with both magmatic and tectonic activity. The zircon U–Pb ages of [...] Read more.

In the Huanggangliang–Ganzhuermiao metallogenic belt in the southern Great Xing’an Range, the Haobugao Pb–Zn deposit is the most widespread skarn-type polymetallic deposit. The observed mineralization processes in this area are closely associated with both magmatic and tectonic activity. The zircon U–Pb ages of two granitoid phases are 134.0 ± 0.6 Ma and 133.4 ± 0.9 Ma (Early Cretaceous). High SiO₂ content (average mass fractions of 77.98 wt.% and 73.25 wt.%), high alkalinity (average mass fractions of 6.19 wt.% and 8.78 wt.%), and low CaO levels (average mass fractions of 0.16 wt.% and 0.12 wt.%) are characteristic of these rocks. They are also enriched in high-field-strength elements (HFSEs) (Th, U, Ta, Zr, Hf, etc.) and depleted in large ion lithophile elements (LILEs) (Ba, Sr, etc.). Furthermore, the Nb/Ta ratios (7.80~8.82, 10.00~10.83) point to a crustal origin of the magma. The zircon Hf isotopic compositions suggest that the melting of young crust derived from Meso-Neoproterozoic and Neoproterozoic depleted mantle gave rise to the magma in these granite porphyries. These rocks formed in an extensional environment driven by the subduction and retreat of the Paleo-Pacific plate during the Early Cretaceous. Full article

(This article belongs to the Special Issue Genesis and Metallogeny of Non-ferrous and Precious Metal Deposits, 2nd Edition)

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32 pages, 26323 KiB

Open AccessArticle

Geochronology and Geochemical Characteristics of Granitoids in the Lesser Xing’an–Zhangguangcai Range: Petrogenesis and Implications for the Early Jurassic Tectonic Evolution of the Mudanjiang Ocean

by Jingui Kong, Kai Qiao, Xiaoyu Huo, Guobin Zhang, Xingkai Chen and Lei Yao

Minerals 2024, 14(9), 941; https://doi.org/10.3390/min14090941 - 15 Sep 2024

Viewed by 945

Abstract

This article focuses on zircon U-Pb isotope dating and a whole-rock elemental analysis of granodiorites, monzonitic granites, granodioritic porphyries, and alkali feldspar granites in the Yangmugang area of the Lesser Xing’an–Zhangguangcai Range. The zircon U-Pb isotope-dating results revealed that these granitic rocks formed [...] Read more.

This article focuses on zircon U-Pb isotope dating and a whole-rock elemental analysis of granodiorites, monzonitic granites, granodioritic porphyries, and alkali feldspar granites in the Yangmugang area of the Lesser Xing’an–Zhangguangcai Range. The zircon U-Pb isotope-dating results revealed that these granitic rocks formed during the late Early Jurassic period (182.9–177.2 Ma). Their geochemical characteristics and zircon saturation temperatures suggest that the granodiorites are moderately differentiated I-type granites and the monzonitic granite, granodioritic porphyries, and alkali feldspar granites are highly differentiated I-type granites. The degree of magma differentiation progressively increased from granodiorites to alkali feldspar granites. By combining the regional Nd and Hf isotope compositions, it was inferred that the magma source involved the melting of lower crustal material from the Mesoproterozoic to the Neoproterozoic eras. By integrating these findings with contemporaneous intrusive rock spatial variations, it was indicated that the late Early Jurassic granitoids in the Lesser Xing’an–Zhangguangcai Range formed within an extensional tectonic setting after the collision and closure of the Songnen–Zhangguangcai Range and Jiamusi blocks. Additionally, this study constrains the closure of the Mudanjiang Ocean to the late Early Jurassic period (177.2 Ma). Full article

(This article belongs to the Special Issue Genesis and Metallogeny of Non-ferrous and Precious Metal Deposits, 2nd Edition)

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14 pages, 6630 KiB

Open AccessArticle

Overprinting Mineralization in the Huoluotai Porphyry Cu (Mo) Deposit, NE China: Evidence from K-Feldspar Ar-Ar Geochronology and S-Pb Isotopes

by Yonggang Sun, Zhongjie Yang, Mingliang Wang, Chengcheng Xie, Xusheng Chen and Fanbo Meng

Minerals 2024, 14(9), 859; https://doi.org/10.3390/min14090859 - 24 Aug 2024

Viewed by 665

Abstract

The Great Xing’an Range (GXR) is a significant belt of polymetallic deposits located in the eastern segment of the Central Asian Orogenic Belt. The recently found Huoluotai porphyry Cu (Mo) deposit is situated in the northern GXR region in northeastern (NE) China. The [...] Read more.

The Great Xing’an Range (GXR) is a significant belt of polymetallic deposits located in the eastern segment of the Central Asian Orogenic Belt. The recently found Huoluotai porphyry Cu (Mo) deposit is situated in the northern GXR region in northeastern (NE) China. The deposit has been studied extensively using field geology and geochronological methods, which have identified two distinct mineralization events. These events include an early occurrence of porphyry-type Cu (Mo) mineralization and a later occurrence of vein-type Cu mineralization. Prior geochronology investigations have determined an approximate age of 147 Ma for the early porphyry-type Cu (Mo) mineralization. ⁴⁰Ar/³⁹Ar dating of K-feldspar of the altered Cu-mineralized quartz diorite porphyry veins for the overprinting vein-type Cu mineralization provides plateau ages of 123.1 ± 1.5 Ma, 122.3 ± 2.8 Ma, and 122.2 ± 0.4 Ma. Sulfide S-Pb isotope compositions of the two mineralization events suggest that both have a magmatic source. The origin of ore-forming metals displays the features of a crust–mantle mixing origin. The regional extensional tectonic setting in NE China during the Early Cretaceous was caused by large-scale lithosphere delamination and upwelling of the asthenospheric mantle. These processes were triggered by the rollback of the Paleo-Pacific Plate. The tectonic event in question resulted in the lithospheric thinning, significant magmatic activity, and mineralization in NE China. Full article

(This article belongs to the Special Issue Genesis and Metallogeny of Non-ferrous and Precious Metal Deposits, 2nd Edition)

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51 pages, 12244 KiB

Open AccessArticle

Mineralogy and Origin of Vein Wolframite Mineralization from the Pohled Quarry, Havlíčkův Brod Ore District, Czech Republic: Interaction of Magmatic and Basinal Fluids

by Zdeněk Dolníček, Jana Ulmanová, Luboš Vrtiška, Karel Malý, Michaela Krejčí Kotlánová and Rostislav Koutňák

Minerals 2024, 14(6), 610; https://doi.org/10.3390/min14060610 - 14 Jun 2024

Cited by 1 | Viewed by 1158

Abstract

Mineralogy and formation conditions were studied in a newly found vein wolframite mineralization, cutting migmatitized paragneisses in the exocontact of a small Carboniferous granite body in the Pohled quarry, Moldanubian Zone of the Bohemian Massif, Czech Republic. The early stage of the rich [...] Read more.

Mineralogy and formation conditions were studied in a newly found vein wolframite mineralization, cutting migmatitized paragneisses in the exocontact of a small Carboniferous granite body in the Pohled quarry, Moldanubian Zone of the Bohemian Massif, Czech Republic. The early stage of the rich mineral assemblage (36 mineral species) involves wolframite, columbite-group minerals, molybdenite, and scheelite hosted by quartz–muscovite–chlorite gangue, which was followed by base-metal sulfides in a quartz gangue, whereas the last stage included calcite gangue with fluorite and minor sulfides. The mineral assemblage points to the mobility of usually hardly soluble elements, including W, Sn, Zr, Nb, Th, Ti, Sc, Y, and REEs. A fluid inclusion study indicates a significant decrease in homogenization temperatures from 350–370 °C to less than 100 °C during vein formation. Fluids were aqueous, with a low salinity (0–12 wt. % NaCl eq.) and traces of CO₂, N₂, CH₄, H₂, and C₂H₆. The δ¹⁸O values of the fluids giving rise to quartz and scheelite are positive (min. 4‰–6‰ V-SMOW). The Eh and pH of the fluid also changed during evolution of the vein. Both wolframite and columbite-group minerals are anomalously enriched in Mg. We suggest that the origin of this distinct mineralization was related to the mixing of Mo,W-bearing granite-derived magmatic fluids with external basinal waters derived from contemporaneous freshwater (but episodically evaporated) piedmont basins. The basinal waters infiltrated into the subsurface along fractures formed in the extensional tectonic regime, and their circulation continued even after the ending of the activity of magmatic fluids. The studied wolframite mineralization represents the most complete record of the ‘hydrothermal’ history of a site adjacent to a cooling granite body in the study area. Moreover, there are broad similarities in the mineral assemblages, textures, and chemical compositions of individual minerals from other occurrences of wolframite mineralization around the Central Moldanubian Plutonic Complex, pointing to the genetic similarities of the Variscan wolframite-bearing veins in this area. Full article

(This article belongs to the Special Issue Genesis and Metallogeny of Non-ferrous and Precious Metal Deposits, 2nd Edition)

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23 pages, 4493 KiB

Open AccessArticle

⁴⁰Ar/³⁹Ar Dating and In Situ Trace Element Geochemistry of Quartz and Mica in the Weilasituo Deposit in Inner Mongolia, China: Implications for Li–Polymetallic Metallogenesis

by Xue Wang, Ke-Yong Wang, Yang Gao, Jun-Chi Chen, Han-Wen Xue and Hao-Ming Li

Minerals 2024, 14(6), 575; https://doi.org/10.3390/min14060575 - 30 May 2024

Cited by 1 | Viewed by 933

Abstract

The Weilasituo Li–polymetallic deposit, located on the western slope of the southern Great Xing’an Range in the eastern Central Asian Orogenic Belt, is hosted by quartz porphyry with crypto-explosive breccia-type Li mineralisation atop and vein-type Sn-Mo-W-Zn polymetallic mineralisation throughout the breccia pipe. This [...] Read more.

The Weilasituo Li–polymetallic deposit, located on the western slope of the southern Great Xing’an Range in the eastern Central Asian Orogenic Belt, is hosted by quartz porphyry with crypto-explosive breccia-type Li mineralisation atop and vein-type Sn-Mo-W-Zn polymetallic mineralisation throughout the breccia pipe. This study introduces new data on multistage quartz and mica in situ trace elements; the study was conducted using laser ablation inductively coupled plasma mass spectrometry and ⁴⁰Ar/³⁹Ar dating of zinnwaldite to delineate the metallogenic age and genesis of Li mineralisation. Zinnwaldite yields a plateau age of 132.45 ± 1.3 Ma (MSWD = 0.77), representing Early Cretaceous Li mineralisation. Throughout the magmatic–hydrothermal process, quartz trace elements showed Ge enrichment. Li, Al, and Ti contents decreased, with Al/Ti and Ge/Ti ratios increasing, indicating increased magmatic differentiation, slight acidification, and cooling. Mica’s rising Li, Rb, Cs, Mg, and Ti contents and Nb/Ta ratio, alongside its falling K/Rb ratio, indicate the magma’s ongoing crystallisation differentiation. Fractional crystallisation primarily enriched Li, Rb, and Cs in the late melt. Mica’s high Sc, V, and W contents indicate a high f_O2 setting, with a slightly lower f_O2 during zinnwaldite formation. Greisenisation observed Zn, Mg, and Fe influx from the host rock, broadening zinnwaldite distribution and forming minor Zn vein orebodies later. Late-stage fluorite precipitation highlights a rise in F levels, with fluid Sn and W levels tied to magma evolution and F content. In summary, the Weilasituo Li–polymetallic deposit was formed in an Early Cretaceous extensional environment and is closely related to a nearby highly differentiated Li-F granite. During magma differentiation, rare metal elements such as Li and Rb were enriched in residual melts. The decrease in temperature and the acidic environment led to the precipitation of Li-, Rb-, and W-bearing minerals, and the increased F content in the late stage led to Sn enrichment and mineralisation. Fluid metasomatism causes Zn, Mg, and Fe in the surrounding rock to enter the fluid, and Zn is enriched and mineralised in the later period. Full article

(This article belongs to the Special Issue Genesis and Metallogeny of Non-ferrous and Precious Metal Deposits, 2nd Edition)

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