Research

26 pages, 18709 KiB

Open AccessFeature PaperArticle

Geochemical and Isotopic Compositions of Fluorites from the Yama Fluorite Deposit in the Qilian Orogen in Northwest China, and Their Metallogenic Implications

by He Jiao, Guo-Biao Huang, Wei Ma, Qiang-Qiang Cui, Wei-Hu Wang, Qing-Feng Ding, Xuan Zhou and Rui-Zhe Wu

Minerals 2024, 14(1), 37; https://doi.org/10.3390/min14010037 - 28 Dec 2023

Viewed by 755

Abstract

The Yama area is characterized by numerous large-scale fluorite–quartz veins that are located along faults within the widespread Late Devonian–Late Silurian syenogranites in the Tataleng granitic batholith, Qilian Orogen, Northwest China. These fluorite–quartz veins contribute to an important fluorite reserve, but their ore [...] Read more.

The Yama area is characterized by numerous large-scale fluorite–quartz veins that are located along faults within the widespread Late Devonian–Late Silurian syenogranites in the Tataleng granitic batholith, Qilian Orogen, Northwest China. These fluorite–quartz veins contribute to an important fluorite reserve, but their ore genesis remains unresolved so far. In this study, trace elements, rare earth elements (REEs), and hydrogen, oxygen, and strontium isotopic compositions of fluorites are analyzed. The studied fluorite samples have similar chondrite-normalized REEs, including Y patterns, with relatively strong enrichment in heavy REEs, negative Eu anomalies, strongly positive Y anomalies, and comparably invariable Y/Ho ratios of 41.43–73.79, suggesting a unique hydrothermal genesis. The relatively variable values of δD and δ¹⁸O are −77.4‰ to −102.4‰ and −12.7‰ to −4.3‰, respectively, close to the meteoric water line. These fluorites yield relatively invariable analytical ⁸⁷Sr/⁸⁶Sr ratios of 0.749089−0.756628 (except for an anomalously high ratio), and their calculated initial ⁸⁷Sr/⁸⁶Sr ratios, based on the ore-forming ages provided, are apparently higher than the calculated initial ⁸⁷Sr/⁸⁶Sr ratios of syenogranite wall rocks. Collectively, the geochemistry of trace elements, REEs, and stable isotopes (H, O, and Sr) suggests that the ore-forming fluids were of meteoric origin and that the Sr sources were directly derived from the ore-forming fluids themselves rather than syenogranite wall rocks. Finally, it was considered that the Yama fluorite deposit is a fault-controlled hydrothermal vein-type deposit which was possibly related to the evolution of the Paleo-Tethys Ocean in the Permian–Triassic. Full article

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

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18 pages, 23050 KiB

Open AccessArticle

Age and Tectonic Setting of Layered Lead–Zinc Ore Bodies in the Xiaohongshilazi Deposit: Constraints from Geochronology and Geochemistry of the Volcanic Rocks in Central Jilin Province, NE China

by Qun Yang, Qingqing Shang, Yunsheng Ren and Zhongjie Yang

Minerals 2023, 13(11), 1371; https://doi.org/10.3390/min13111371 - 27 Oct 2023

Viewed by 833

Abstract

The newly discovered Xiaohongshilazi deposit located in Panshi City, central Jilin Province, NE China, is a medium-scale Pb–Zn–(Ag) deposit. The Pb–Zn–(Ag) orebodies are divided into layered and vein-type orebodies, which have different ore geneses. The layered Pb–Zn orebodies are mainly hosted within and [...] Read more.

The newly discovered Xiaohongshilazi deposit located in Panshi City, central Jilin Province, NE China, is a medium-scale Pb–Zn–(Ag) deposit. The Pb–Zn–(Ag) orebodies are divided into layered and vein-type orebodies, which have different ore geneses. The layered Pb–Zn orebodies are mainly hosted within and spatially controlled by the volcanic rocks. To constrain the age and tectonic setting of the layered Pb–Zn mineralization, we completed laser-ablation–ICP–MS zircon U–Pb dating and whole-rock major and trace element analyses of the ore-bearing volcanic rocks. The dacite samples were confirmed as belonging to the Daheshen Formation and were the main ore-bearing volcanic rocks for the layered orebodies. They yielded concordia U–Pb ages of 278.1 ± 1.8 Ma and 278.3 ± 1.8 Ma, respectively, indicating that the volcanic rocks from the Daheshen Formation and related layered Pb–Zn mineralization were formed in the early Permian. The andesite and rhyolite located above the layered orebodies yielded concordia U–Pb ages of 225.0 ± 1.1 Ma, 225.3 ± 1.5 Ma, and 224.7 ± 1.2 Ma, respectively; these substances are considered to be of the Sihetun Formation and were first reported in the area. The dacite samples associated with layered Pb–Zn mineralization were high in SiO₂ (62.54–65.02 wt.%), enriched in LREEs and LILEs (e.g., Rb, Ba, and K), and showed depletion in HFSEs (e.g., P and Ti). It showed slightly negative Eu anomalies (δEu = 0.60–0.65) and negative Nb anomalies, with Th/Nb (1.12–1.21) and La/Nb (2.8–4.7) ratios, presenting subduction-related arc magma affinity formed in an active continental margin setting. In agreement with previous studies on zircon Hf isotopes (ε_Hf (t) = +0.23~ +10.60) of the volcanic rocks from the Daheshen Formation, we infer that they were derived from the partial melting of the depleted lower crust. In conclusion, mineralization characteristics, geochronological data, geochemical features, and regional tectonic evolution suggest that two Pb–Zn–(Ag) mineralization stages from the Xiaohongshilazi deposit occurred: the layered VMS-type Pb–Zn mineralization associated with the marine volcanic rocks from the early Permian Daheshen Formation, which was induced by the subduction of the Paleo-Asian oceanic plate beneath the northern margin of the North China Craton, and the vein-type Pb–Zn–(Ag) mineralization caused by the subduction of the Paleo-Pacific Plate in the early Jurassic. Considering this, along with the mineralization characteristics of the same-type polymetallic deposits in this region, we propose that the early Permian marine volcanic rocks have great prospecting potential for the VMS-type Pb–Zn polymetallic deposits. Full article

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

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26 pages, 23305 KiB

Open AccessArticle

Fluid Evolution and Ore Genesis of the Songjianghe Au Deposit in Eastern Jilin Province, NE China: Constraints from Fluid Inclusions and H-O-S-Pb Isotope Systematics

by Qi Yu, Keyong Wang, Xuebing Zhang, Qingfei Sun, Wenqiang Bai, Chao Ma and Yongchun Xiao

Minerals 2023, 13(5), 652; https://doi.org/10.3390/min13050652 - 09 May 2023

Cited by 1 | Viewed by 1574

Abstract

The medium-sized Songjianghe Au deposit is located in the southeastern part of the Jiapigou-Haigou gold belt (JHGB) in central eastern Jilin Province, NE China. The gold mineralization is primarily characterized by disseminated-style ores and hosted in the low-/medium-grade metamorphic rocks of the Seluohe [...] Read more.

The medium-sized Songjianghe Au deposit is located in the southeastern part of the Jiapigou-Haigou gold belt (JHGB) in central eastern Jilin Province, NE China. The gold mineralization is primarily characterized by disseminated-style ores and hosted in the low-/medium-grade metamorphic rocks of the Seluohe Group. The ore bodies are governed by NNW-striking brittle-ductile structures and spatially correlated with silicic and sericitic alterations. Four alteration/mineralization stages have been distinguished: (I) Quartz-pyrrhotite-pyrite, (II) quartz-polymetallic sulfides, (III) quartz-pyrite, and (IV) quartz-calcite. The fluid inclusion (FI) assemblage in quartz from Stage I comprises C1-type, C2-type, C3-type, and VL-type FIs, with total homogenization temperatures (Th-total) of 292.8 to 405.6 °C and salinities of 2.8 to 9.3 wt% NaCl eqv. Quartz from Stage II (main ore stage) developed C2-, C3-, and VL-type FIs, with a Th-total of 278.5 to 338.9 °C and salinities of 2.8 to 8.1 wt% NaCl eqv. Stage III is characterized by coexisting C3- and VL-type FIs in quartz, with a Th-total of 215.9 to 307.3 °C and salinities of 2.4 to 7.2 wt% NaCl eqv. Only VL-type FIs are observed in Stage IV, with a Th-total of 189.5 to 240.4 °C and salinities of 3.7 to 5.7 wt% NaCl eqv. The Laser Raman spectroscopic results demonstrated minor CH₄ in the C-type FIs from Stages I and II. The results suggest that ore fluids may have evolved from a medium-high temperature, low-salinity immiscible CO₂-NaCl-H₂O ± CH₄ system to a low temperature, low-salinity homogeneous NaCl-H₂O system. Fluid immiscibility caused by the rapid drop in pressure may have been the main trigger for gold-polymetallic sulfide precipitation. The Songjianghe Au deposit may have been formed under 352–448 °C and 850–1380 bar pressure, based on the isochore intersection for Stage II fluid inclusions. The H-O isotopic compositions (Stage I: δ¹⁸O_fluid = 5.6 to 5.8‰, δD = −96.2 to −95.7‰; Stage II: δ¹⁸O_fluid = 3.7 to 4.2‰, δD = −98.7 to −89.8‰; Stage III: δ¹⁸O_fluid = 1.2 to 1.4‰, δD = −103.5 to −101.2‰) indicate that the hydrothermal fluids are dominated by magmatic water in the early stages (Stages I and II) and mixed with meteoric water since Stage III. The pyrite S-Pb isotope data (δ³⁴S: −2.91 to 3.40‰; ²⁰⁶Pb/²⁰⁴Pb: 16.3270 to 16.4874; ²⁰⁷Pb/²⁰⁴Pb: 15.2258 to 15.3489; ²⁰⁸Pb/²⁰⁴Pb: 36.6088 to 36.7174), combined with Pb isotopic compositions of the intrusive rocks and wall rocks (the Seluohe Group) in the ore district, indicate that the ore-forming materials at Songjianghe are predominantly from a magmatic source and may have been affected by the contamination of the Seluohe Group. In accordance with the features of ore geology, ore-forming fluids and metals, and geodynamic setting, the Songjianghe Au deposit belongs to a mesothermal magmatic hydrothermal vein gold deposit, which formed in the intermittent stage of Paleo-Pacific plate subduction during the Late Jurassic. Full article

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

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25 pages, 5892 KiB

Open AccessArticle

Automated Hyperparameter Optimization of Gradient Boosting Decision Tree Approach for Gold Mineral Prospectivity Mapping in the Xiong’ershan Area

by Mingjing Fan, Keyan Xiao, Li Sun, Shuai Zhang and Yang Xu

Minerals 2022, 12(12), 1621; https://doi.org/10.3390/min12121621 - 16 Dec 2022

Cited by 3 | Viewed by 2105

Abstract

The weak classifier ensemble algorithms based on the decision tree model, mainly include bagging (e.g., fandom forest-RF) and boosting (e.g., gradient boosting decision tree, eXtreme gradient boosting), the former reduces the variance for the overall generalization error reduction while the latter focuses on [...] Read more.

The weak classifier ensemble algorithms based on the decision tree model, mainly include bagging (e.g., fandom forest-RF) and boosting (e.g., gradient boosting decision tree, eXtreme gradient boosting), the former reduces the variance for the overall generalization error reduction while the latter focuses on reducing the overall bias to that end. Because of its straightforward idea, it is prevalent in MPM (mineral prospectivity mapping). However, an inevitable problem in the application of such methods is the hyperparameters tuning which is a laborious and time-consuming task. The selection of hyperparameters suitable for a specific task is worth investigating. In this paper, a tree Parzen estimator-based GBDT (gradient boosting decision tree) model (TPE-GBDT) was introduced for hyperparameters tuning (e.g., loss criterion, n_estimators, learning_rate, max_features, subsample, max_depth, min_impurity_decrease). Then, the geological data of the gold deposit in the Xiong ‘ershan area was used to create training data for MPM and to compare the TPE-GBDT and random search-GBDT training results. Results showed that the TPE-GBDT model can obtain higher accuracy than random search-GBDT in a shorter time for the same parameter space, which proves that this algorithm is superior to random search in principle and more suitable for complex hyperparametric tuning. Subsequently, the validation measures, five-fold cross-validation, confusion matrix and success rate curves were employed to evaluate the overall performance of the hyperparameter optimization models. The results showed good scores for the predictive models. Finally, according to the maximum Youden index as the threshold to divide metallogenic potential areas and non-prospective areas, the high metallogenic prospect area (accounts for 10.22% of the total study area) derived by the TPE-GBDT model contained > 90% of the known deposits and provided a preferred range for future exploration work. Full article

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

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17 pages, 13120 KiB

Open AccessArticle

Geology, Mineralogy, and Age of Li-Bearing Pegmatites: Case Study of Tochka Deposit (East Kazakhstan)

by Natalya A. Zimanovskaya, Tatyana A. Oitseva, Sergey V. Khromykh, Alexey V. Travin, Ainel Y. Bissatova, Irina Yu. Annikova and Saltanat S. Aitbayeva

Minerals 2022, 12(12), 1478; https://doi.org/10.3390/min12121478 - 22 Nov 2022

Cited by 1 | Viewed by 2256

Abstract

New geological, mineralogical, geochemical, and geochronological data have been obtained for Li-bearing pegmatites from the Tochka deposit located within the Karagoin–Saryozek zone in East Kazakhstan. Earlier, the exploration works in this zone were carried out to detect only Ta and Sn mineralization, but [...] Read more.

New geological, mineralogical, geochemical, and geochronological data have been obtained for Li-bearing pegmatites from the Tochka deposit located within the Karagoin–Saryozek zone in East Kazakhstan. Earlier, the exploration works in this zone were carried out to detect only Ta and Sn mineralization, but other ores (including Li) were not considered. The estimation of lithium resources in pegmatites from the area was methodologically imperfect. Previously, it was believed that the formation of rare-metal pegmatite veins was associated with Late Carboniferous Na-granites. The obtained geological observation confirms that the ore-bearing rare-metal pegmatites at the Tochka deposits cut the Late Carboniferous Na-granites and do not cut the Early Permian Kalba granites. The associations of the accessory minerals in host hornfels, Na-granites, and rare-metal pegmatites are different and the accessory minerals in pegmatites are similar to the accessory minerals in the Kalba granites. Geochemical data show that the behavior of rare elements (Ba, Th, HFSE, and REE) and the levels of accumulation of rare metals prove that pegmatites are similar to the product of the differentiation of the granitic magmas of the Kalba complex. The ⁴⁰Ar/³⁹Ar muscovite age of the Tochka pegmatites (~292 Ma) fits the age range of the Kalba granite complex. Based on the main principles of the generation of rare-metal pegmatites, the Tochka pegmatites formed during the fluid–magmatic fractionation of magma in large granitic reservoirs of the Kalba complex. The Karagoin–Saryozek zone—located between several large granite massifs of the Kalba complex where host rocks play a role as a roof—may be very promising for rare-metal pegmatite mineralization. Full article

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

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23 pages, 5782 KiB

Open AccessArticle

Magma Evolution and Constraints on the Graphite Mineralization Hosted by the Huangyangshan Alkaline Granite Suite in the East Junggar of Xinjiang Province: Evidence from In Situ Analyses of Silicate Minerals

by Xinhao Sun, Yunsheng Ren, Jingmou Li, Mengjia Huang, Zhenjun Sun and Zuowu Li

Minerals 2022, 12(11), 1458; https://doi.org/10.3390/min12111458 - 18 Nov 2022

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Abstract

The Huangyangshan super-large graphite deposit, located in the East Junggar area of the Xinjiang Province, is hosted in and has closely temporal, spatial, and genetic relationships with the Huangyangshan alkaline granites. There are such silicate minerals as amphibole, biotite, pyroxene, and plagioclase occurring [...] Read more.

The Huangyangshan super-large graphite deposit, located in the East Junggar area of the Xinjiang Province, is hosted in and has closely temporal, spatial, and genetic relationships with the Huangyangshan alkaline granites. There are such silicate minerals as amphibole, biotite, pyroxene, and plagioclase occurring in the graphite-bearing granites. The integration of the electron microprobe analysis (EMPA) and laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) enabled us to reveal the physicochemical conditions and evolution process, as well as the relationship of alkaline magmatism with graphite mineralization. The results show that the amphiboles generally have low Al and high Ti, K, Si, and Fe contents, as well as similar rare-earth elements (REEs) patterns and trace element distribution patterns to granites with significantly negative Eu anomalies. In the analyzed samples, primary biotite belongs to Fe-biotite and has characteristics of high Si and Fe and low Al and Mg contents. In the graphite orbicules, the pyroxene phenocrysts develop multiple zonal structures and are characterized by high Si and low Ca and Fe contents. The dominant plagioclase phenocrysts in the graphite orbicules are oligoclase and andesine, with normal and occasionally oscillatory zoning. The calculated crystallization temperature of the pyroxene, amphibole, and primary biotite in graphite orbicules are 840–1012 °C, 681–761 °C, and 658–720 °C, respectively, corresponding with their crystallization order. The pressure and depth calculation results of the amphibole, representing those of the magmatism, are 157–220 Mpa and 5.95–8.32 km, respectively. Both amphibole and biotite crystallized in a reducing environment with extremely low oxygen fugacity. The elemental compositions of these silicates indicate that the Huangyangshan pluton experienced significant mixing of mafic mantle-derived magma and felsic crust-derived magma. The cores of graphite orbicules were formed in a relatively earlier magmatic stage, while the granites and their dioritic enclaves were formed in a later magmatic stage. During magmatism, the mixing of mantle-derived basic magma had an important influence on the evolution and differentiation of the melts. According to the coexisting sulfides with graphite and compositional difference of amphibole and biotite in the granites and graphite ores, the graphite mineralization might be triggered by a magma mixing process. Full article

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

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18 pages, 3812 KiB

Open AccessArticle

Genesis of Metal Sulfides and Its Significance on Graphite Mineralization in the Huangyangshan Graphite Deposit, East Junggar, Xinjiang Province, China

by Yunsheng Ren, Jingmou Li, Xinhao Sun, Zuowu Li and Zhenjun Sun

Minerals 2022, 12(11), 1450; https://doi.org/10.3390/min12111450 - 16 Nov 2022

Cited by 3 | Viewed by 1527

Abstract

The Huangyangshan super-large graphite deposit is located in the Qitai area of East Junggar in Xinjiang Province, China. This deposit is well known for its distinguishing properties, including the alkaline granite complex that hosts the graphite ore, the dominantly orbicular structure developed in [...] Read more.

The Huangyangshan super-large graphite deposit is located in the Qitai area of East Junggar in Xinjiang Province, China. This deposit is well known for its distinguishing properties, including the alkaline granite complex that hosts the graphite ore, the dominantly orbicular structure developed in the graphite ore, and the association of graphite with metal sulfides in the orbicular ore. This study aims to determine the genetic relationship between graphite and metal sulfides in order to better understand the graphite mineralization process of the Huangyangshan deposit. The methods applied in the study include X-ray micro-CT scanning and scanning electron microscopy (SEM) analyses of the orbicular graphite ore and in situ inductive laser ablation-coupled plasma mass spectrometry (LA-ICP-MS) trace element analyses of the pyrrhotite and chalcopyrite associated with the graphite. The analytical results show that the graphite ore is composed of crystalline graphite, K-feldspar, albite, quartz, biotite, amphibole, and metal sulfides. The metal sulfides in the orbicular ore include pyrite, pyrrhotite, pentlandite, and chalcopyrite. According to the color, crystalline shape, texture, and occurrence, pyrrhotite can be classified into four types (I, II, III, and IV), and chalcopyrite into two types (I and II), of which types I, II, and III pyrrhotite and type I chalcopyrite have a close genetic relationship with graphite. The granular types (I, II, and III) of pyrrhotite are enriched in Co, Ni, Se, Ge, and Te and are depleted in As, Sb, Ag, and Au; they also have a high value of Co/Ni, indicating that these types of pyrrhotite have a magmatic origin. Low values of Co/Ni suggest that type IV pyrrhotite has a hydrothermal origin. The similar contents of Co and Ni and the values of Co/Ni compared with the chalcopyrite from the magmatic Co–Ni sulfide deposits imply that type I chalcopyrite has a magmatic origin. In summary, the metal sulfides of the Huangyangshan deposit are genetically related to graphite mineralization and formed predominantly by magmatic processes. Full article

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

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23 pages, 8669 KiB

Open AccessArticle

Microscopic Characteristics and Formation Mechanism of Effective Reservoirs in the Xihu Depression, China: The Important Role of the Poikilotopic Calcite Cements in Tide-Dominated Delta Systems

by Songxu Zhang, Keqiang Wu, Na Liu, Xiaolei Peng and Ying Chen

Minerals 2022, 12(11), 1413; https://doi.org/10.3390/min12111413 - 07 Nov 2022

Cited by 1 | Viewed by 1795

Abstract

The Xihu depression is an offshore sag located on the East China Sea Shelf Basin, which is currently one of the major oil and gas basins along the coast of China. In this study, an integrated approach using thin sections, scanning electron microscopy [...] Read more.

The Xihu depression is an offshore sag located on the East China Sea Shelf Basin, which is currently one of the major oil and gas basins along the coast of China. In this study, an integrated approach using thin sections, scanning electron microscopy (SEM), X-ray diffraction (XRD), cathodoluminescence (CL), high-resolution 3D CT core scanning and stable isotope analysis was applied to examine the diagenetic evolution and investigate the microscopic characteristics and formation mechanisms associated with effective reservoirs. Four types were distinguished: upper conventional reservoirs (UC reservoirs), lower conventional reservoirs (LC reservoirs), “bottom calcium” low-permeability reservoirs (“bottom calcium” reservoirs) and “MI clay” low-permeability reservoirs (“MI clay” reservoirs). Poikilotopic calcite cements play an important role in the diagenetic alterations and reservoir quality evolution, precipitating during early eogenesis, provided a framework that retards the adverse impacts of UC reservoirs by compaction. Conversely, in LC reservoirs, with limited poikilotopic calcite, secondary porosity is mostly due to the dissolution of feldspar or unstable rock fragments. UC reservoirs normally develop in the middle of tidal channels and in subaqueous distributary channels, with the base of the sand-body being extensively cemented by carbonate cements, such as late calcite, Fe-calcite and dolomite, which formed the “bottom calcium” reservoir. Combined evidence from petrographic and geochemical analyses suggests that calcite precipitates from diagenetic fluids of mixed marine and meteoric waters, with additional external sources from calcareous siltstones and bioclasts. The carbon sources of calcite mostly originate from the dissolution of carbonates clacts or bioclasts within sandstone beds or adjacent silty mudstones, while dolomite cements have an isotopic composition that is more comparable to the generation of biogenic methane. This study demonstrates how poikilotopic calcite, developed in tide-dominated delta systems, affects the vertical heterogeneity. The results can be used to improve the reservoir evolution model of tide-dominated delta systems and provide a basic understanding for researchers conducting reservoir studies of similar sedimentary systems. Our results can act as a geological basis for further oil and gas exploration. Full article

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

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19 pages, 4959 KiB

Open AccessArticle

Provenance Tracing and Age Analysis of Lead–Zinc Mineralization in Qiyimuchang, Inner Mongolia, NE China

by Mingxin Duan, Yunsheng Ren, Chunji Xue, Qun Yang, Yujie Hao and Tao Liu

Minerals 2022, 12(9), 1146; https://doi.org/10.3390/min12091146 - 10 Sep 2022

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Abstract

The Qiyimuchang lead–zinc deposit is an important deposit in the Erguna Massif on the west slope of Daxinganling, for which the material source and age of mineralization remain unclear. The lead–zinc deposit in Qiyimuchang has been observed to occur in Jurassic volcanic strata [...] Read more.

The Qiyimuchang lead–zinc deposit is an important deposit in the Erguna Massif on the west slope of Daxinganling, for which the material source and age of mineralization remain unclear. The lead–zinc deposit in Qiyimuchang has been observed to occur in Jurassic volcanic strata as a vein-like orebody, and its strike is nearly perpendicular to that of the strata and the regional structures of the orogenic belt. The ore is mainly composed of sphalerite, galena, chalcopyrite, pyrite, and quartz, and hydrothermal alteration zones dominated by silicification, fluoritization, and pyritization are common within 1–5 m on both sides of the vein. The metasomatic lead–zinc mineralization is characterized by a massive vein structure. The mineralization process can be divided into three stages, pre-ore (mainly quartz, arsenopyrite and a small amount of pyrite), ore-formation (pyrite, chalcopyrite, sphalerite, galena, fluorite, and a small amount of tetrahedrite), and post-ore (quartz-calcite veinlets with a small amount of pyrite). Element and isotope geochemical studies show that the trace element compositions of the wall rocks (andesite, tuff, etc.) of Jurassic volcanic rocks in the ore bodies and surrounding rocks reflect affinity or similarity between them. The S isotopic composition of sulfide minerals in the metallogenic stage (δ ³⁴S_V-CDT = 1.6‰~4.8‰) indicate the sulfur isotopic composition of the magma. The Pb isotopic compositions of sulfide minerals (38.5–38.39, 15.55–15.62, and 18.33–18.41 for ²⁰⁸Pb/²⁰⁴Pb, ²⁰⁷Pb/²⁰⁴Pb, and ²⁰⁶Pb/²⁰⁴Pb, respectively) in the metallogenic stage are relatively concentrated and close to the average Pb isotopic compositions of the mantle and average Pb isotopic composition of an orogenic belt, indicating that the ore-forming metals are likely to be a mixed source of crust and mantle. A new zircon U-Pb age of 150.8 ± 1.3 Ma (MSWD = 0.74) was obtained from andesitic tuff. Collectively considering the regional geology and ore deposit geological analysis, the lead–zinc mineralization in Qiyimuchang possibly occurred during the early Cretaceous. The ore-forming processes belong to Cretaceous magmatic-hydrothermal activity in extensional tectonic setting. Full article

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

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19 pages, 12078 KiB

Open AccessArticle

Multi-Step Gold Refinement and Collection Using Bi-Minerals in the Laozuoshan Gold Deposit, NE China

by Lin Meng, Fei Huang, Wenyuan Gao, Rongzhen Gao, Fude Zhao, Yiran Zhou and Yongli Li

Minerals 2022, 12(9), 1137; https://doi.org/10.3390/min12091137 - 07 Sep 2022

Cited by 1 | Viewed by 1777

Abstract

Gold and Bi-bearing parageneses are pivotal to understanding gold concentration and deposition processes. The large-scale Laozuoshan gold deposit is located in the Jiamusi Block, northeastern China, and has experienced complex mineralization processes with abundant gold and Bi-bearing minerals. However, the relationship between Bi-minerals [...] Read more.

Gold and Bi-bearing parageneses are pivotal to understanding gold concentration and deposition processes. The large-scale Laozuoshan gold deposit is located in the Jiamusi Block, northeastern China, and has experienced complex mineralization processes with abundant gold and Bi-bearing minerals. However, the relationship between Bi-minerals and gold is unclear, preventing our understanding of the gold enrichment and precipitation mechanism in the Laozuoshan gold deposit. Optical microscope and SEM results show three stages of gold mineralization: pyrrhotite (Po-1) + arsenopyrite (Apy-1) + Bi-bearing minerals (Bis-1) + Au-1; arsenopyrite (Apy-2) + chlorite + Bi-bearing minerals (Bis-2) + Au-2; and arsenopyrite (Apy-3) + graphite + Bi-bearing minerals (Bis-3) + Au-3. The abundant amount of gold (Au-1~Au-3) is associated with Bi-bearing minerals (Bis-1~Bis-3), which coexist as inclusions and fill in fractures in these minerals. The mineral assemblages of arsenopyrite, Bi-minerals, and gold exhibit a clear As-Bi-Au mineralogy in the ores, and the ternary diagram of the chemical compositions of the Bi-minerals shows that Bi-minerals all fall in reducing regions, indicating that Bi-minerals are precipitated under reducing conditions. The gold compositions demonstrate a positive correlation (R² = 0.58) between Au and Bi. Consequently, we propose that the gold experienced the ore-forming fluids concentration and further Bi-melts scavenging for the Laozuoshan gold deposit mineralization. The Bi collector model is essential in interpreting the high-grade gold in the Laozuoshan gold deposit, indicating that the geochemical anomalies observed with bismuth may be a critical potential exploration target for the high-grade gold deposits in the Jiamusi Block. Full article

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

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29 pages, 4643 KiB

Open AccessArticle

Contrasting Sources and Related Metallogeny of the Triassic and Jurassic Granitoids in the Chifeng–Chaoyang District, Northern Margin of the North China Craton: A Review with New Data

by Jian-Guo Yuan, Hua-Feng Zhang, Ying Tong, Yun-Yan Qu, Rui-Bin Liu and Run-Wu Li

Minerals 2022, 12(9), 1117; https://doi.org/10.3390/min12091117 - 01 Sep 2022

Cited by 1 | Viewed by 1266

Abstract

Understanding of the mechanism between magma sources and metallogeny is still vague. As an important gold and molybdenum producing area, the Chifeng–Chaoyang district, located at the northern margin of the North China Craton (NCC), is a key place for this issue. New geochemical [...] Read more.

Understanding of the mechanism between magma sources and metallogeny is still vague. As an important gold and molybdenum producing area, the Chifeng–Chaoyang district, located at the northern margin of the North China Craton (NCC), is a key place for this issue. New geochemical data relating to Taijiying gold-deposit-related granites are presented. These data, coupled with previous studies, are used to explore the relationship between magma sources and mineralization processes. Two major magmatic periods, the Middle Triassic (220–230 Ma) and Late Jurassic (150–160 Ma), are identified based on the compiled data. The Triassic magmatic rocks are mostly fractionated I-type and A-type granites, including monzogranite, biotite granite, and syenogranite. They have low initial ⁸⁷Sr/⁸⁶Sr values (0.7050), moderately enriched ε_Nd(t)–ε_Hf(t) values (−8.5 and −5.6), and relatively young Nd–Hf model ages (T_DM2-T_DM^C) (1.47–1.57 Ga). These features indicate that more Archean–Paleoproterozoic mantle-derived materials were involved in their sources. On the other hand, Jurassic granites are high-K calc-alkaline of the calc-alkaline series and mainly consist of granite, monzogranite, leucogranite, and granodiorite. They have high Na₂O/K₂O, Sr/Y, and La/Yb ratios and low Y and Yb contents. The adakitic features suggest the existence of a thickened lower crust. Their significant negative ε_Nd(t)–ε_Hf(t) values (−15.0 and −12.8) and older Nd–Hf model ages (T_DM2–T_DM^C) (2.17–2.11 Ga) are consistent with their derivation from thickened ancient lower crust, indicating the initial activation of NCC. It is proposed that the change in the main source resulted from the tectonic transition during the early Mesozoic initial decratonization, that is, from the post-collisional extension to the subduction of the Paleo-Pacific plate beneath the East Asia plate from the Triassic to the Jurassic. Comparative analysis suggests that the medium–large-scale gold deposits with a high grade are closely related to the Triassic granites; however, most molybdenum deposits formed in the Jurassic. The decratonization of the NCC in the early Mesozoic experienced tectonic transition and controlled the gold and molybdenum mineralizations in the different stages by the changing magma sources. This pattern is beneficial to understanding the metallogenesis in the Chifeng–Chaoyang district. Full article

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

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28 pages, 11969 KiB

Open AccessArticle

Mesozoic Magmatic and Geodynamic Evolution in the Jiaodong Peninsula, China: Implications for the Gold and Polymetallic Mineralization

by Bin Wang, Zhengjiang Ding, Zhongyi Bao, Mingchun Song, Jianbo Zhou, Junyang Lv, Shanshan Wang, Qibin Zhang and Caijie Liu

Minerals 2022, 12(9), 1073; https://doi.org/10.3390/min12091073 - 25 Aug 2022

Cited by 5 | Viewed by 1388

Abstract

The intrusive age ranges of Linglong, Guojialing, Weideshan, and Laoshan granites in the Jiaodong Peninsula are 155–154 Ma, 131–130 Ma, 118–111 Ma, and 116 Ma, respectively. Together with the Shidao granite (227–200 Ma), five phases of magmatism can be classified by the time, [...] Read more.

The intrusive age ranges of Linglong, Guojialing, Weideshan, and Laoshan granites in the Jiaodong Peninsula are 155–154 Ma, 131–130 Ma, 118–111 Ma, and 116 Ma, respectively. Together with the Shidao granite (227–200 Ma), five phases of magmatism can be classified by the time, all of which have different degrees of gold and polymetallic mineralization. The type of granites evolved from A–, S–type to I–, A–type from the Late Triassic to the Early Cretaceous, thus reflects the evolution of geodynamics in the Mesozoic, indicating the switch from North China Craton (NCC)–Yangtze Craton (YC) collision to subduction of the Paleo–Pacific Plate (PPP), with crustal thickening switching to lithospheric thinning and a compressional tectonic setting changing to an extensional setting. It directly leads to a series of extensional structures evolving in the Jiaodong Peninsula and demonstrates affinity for the extensive mineralization in the Early Cretaceous. The key markers of Jiaodong gold and polymetallic mineralization are magmatism, fluid activity and extensional structure. Extensive magmatic uplift and extensional structures in the Early Cretaceous formed the extensional tectonic system. During the formation process, a large proportion of crust and mantle materials exchanged and mixed, and the fluid interaction was highly active, resulting in a magmatic fluid metallogenic system, which provided favorable metallogenic conditions for gold and nonferrous metal hydrothermal deposits. Thus, a large-scale explosive mineralization occurred in Jiaodong in the middle and late Early Cretaceous. Full article

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

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19 pages, 15251 KiB

Open AccessArticle

Fluid Inclusions and C–H–O–S–Pb Isotopes of the Huoluotai Porphyry Cu (Mo) Deposit in the Northern Great Xing’an Range, NE China: Implications for Ore Genesis

by Yonggang Sun, Bile Li, Xusheng Chen, Fanbo Meng, Qingfeng Ding, Ye Qian and Linlin Wang

Minerals 2022, 12(9), 1072; https://doi.org/10.3390/min12091072 - 25 Aug 2022

Viewed by 1234

Abstract

The Huoluotai Cu (Mo) deposit is a recently discovered porphyry Cu deposit in the northern Great Xing’an Range, NE China. Fluid inclusion (FI) micro-thermometry results and the C–H–O–S–Pb isotope compositions of the Huoluotai Cu (Mo) deposit are presented in this study. The ore-forming [...] Read more.

The Huoluotai Cu (Mo) deposit is a recently discovered porphyry Cu deposit in the northern Great Xing’an Range, NE China. Fluid inclusion (FI) micro-thermometry results and the C–H–O–S–Pb isotope compositions of the Huoluotai Cu (Mo) deposit are presented in this study. The ore-forming process consists of the sulfide-barren quartz stage (I), the quartz + chalcopyrite ± pyrite ± molybdenite stage (II), the quartz + polymetallic sulfide stage (III), and the quartz + calcite ± pyrite ± fluorite stage (IV). Cu mineralization occurred mainly in stage II. Four types of FIs were recognized: liquid-rich two-phase FIs (L-type), vapor-rich two-phase FIs (V-type), daughter-mineral-bearing three-phase FIs (S-type), and CO₂-bearing FIs (C-type). In stage I, the ore-forming fluids belong to an H₂O−NaCl−CO₂ system. In stages II, III, and IV, the ore-forming fluids belong to an H₂O−NaCl system. The results of the FI micro-thermometry and H–O isotope analysis show that the ore-forming fluids originated from a magmatic origin in stage I and mixed with meteoric water from stages II to IV. The S–Pb isotope results suggest that the source of the ore-forming materials has the characteristics of a crust–mantle-mixing origin. Fluid boiling occurred in stages I and II. The FI micro-thermometric data further show that Cu was mainly deposited below 400 °C in stage II, suggesting that fluid boiling occurring below 400 °C may be the primary factor for Cu precipitation in the Huoluotai Cu (Mo) deposit. Full article

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

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25 pages, 7509 KiB

Open AccessArticle

Age, Genesis and Tectonic Setting of the Sayashk Tin Deposit in the East Junggar Region: Constraints from Lu–Hf Isotopes, Zircon U–Pb and Molybdenite Re–Os Dating

by Zhenjun Sun, Guanghu Liu, Yunsheng Ren, Xi Chen, Xinhao Sun, Chengyang Wang and Zuowu Li

Minerals 2022, 12(9), 1063; https://doi.org/10.3390/min12091063 - 23 Aug 2022

Cited by 1 | Viewed by 1286

Abstract

The Sayashk tin (Sn) deposit is located within the southern part of the Eastern Junggar orogenic belt in Xinjiang Province and forms part of the Kalamaili alkaline granite belt. There are many Sn polymetallic deposits in the area. To constrain the age, genesis, [...] Read more.

The Sayashk tin (Sn) deposit is located within the southern part of the Eastern Junggar orogenic belt in Xinjiang Province and forms part of the Kalamaili alkaline granite belt. There are many Sn polymetallic deposits in the area. To constrain the age, genesis, and tectonic setting of the Sayashk tin deposit in the East Junggar region, we conducted a bulk-rock geochemical analysis of the granite porphyry (SR1) and medium- to fine-grained granite (SR2) hosts of the deposit, LA-ICP-MS zircon U–Pb dating and Lu–Hf isotopic analysis, as well as molybdenite Re–OS dating and combined our results with the metallogenic conditions and other geological characteristics of the deposit. The results show that the Sayashk Sn deposit is indeed spatially, temporally, and genetically closely related to the granite porphyry and medium-fine-grained granite. Both zircon U–Pb ages are 308.2 ± 1.5 Ma and 310.9 ± 1.5 Ma, respectively. The isochron age of molybdenite is 301.4 ± 6.7 Ma, which represents the crystallization age of the granite porphyry and medium-fine-grained granite. Therefore, all of them formed in the late Carboniferous epoch. The medium-fine-grained granites and granite porphyry are characteristically rich in Si and alkali, poor in Ca and Mg, rich in high field-strength elements (HFSE, e.g., Zr, Hf) and Ce, and deficient in Ba, Sr, Eu, P, and Ti. They are typical A-type granites, showing the characteristics of a mixed crustal mantle source. The εHf(t) values of the zircon from the granite porphyry (SR1) range from 10.27 to 16.17 (average 13.71), εHf(t) values of the zircon from the medium-fine-grained granites (SR2) are between 5.72 and 9.21 (average 7.08), and the single model ages (T_DM1) and two-stage model ages (T_DM2) of the granite porphyry (SR1) fall within the ranges of 319~535 Ma and 339~644 Ma. The single model ages (T_DM1) and two-stage model ages (T_DM2) of the medium-fine-grained granites (SR2) fall within the ranges of 346~479 Ma and 309~557 Ma. There is little difference between their two-stage model ages and zircon U–Pb ages, indicating that the Sayashk granite may be the product of partial melting of juvenile crustal. Combined with previous research results, the Sayashk Sn deposit formed in a post-collision extensional tectonic setting after the late Carboniferous in the Kalamaili area. Full article

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

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16 pages, 7836 KiB

Open AccessArticle

Geochemical Data Mining by Integrated Multivariate Component Data Analysis: The Heilongjiang Duobaoshan Area (China) Case Study

by Zhonghai Zhao, Kai Qiao, Yiwen Liu, Jun Chen and Chenglu Li

Minerals 2022, 12(8), 1035; https://doi.org/10.3390/min12081035 - 17 Aug 2022

Cited by 7 | Viewed by 2036

Abstract

The Heilongjiang Duobaoshan area is located at the confluence of the Great Xing’an Range and the Lesser Xing’an Range, and the area has undergone a complex magmatic and tectonic evolutionary history resulting in a complex and diverse geological background for mineralization. As a [...] Read more.

The Heilongjiang Duobaoshan area is located at the confluence of the Great Xing’an Range and the Lesser Xing’an Range, and the area has undergone a complex magmatic and tectonic evolutionary history resulting in a complex and diverse geological background for mineralization. As a result of this geological complexity and the multi-period nature of mineralization, the geochemical data of the area are usually not satisfied with a single statistical distribution form, so traditional statistical methods cannot adequately explore and identify the distribution of deep-seated information in the geochemical data. Based on the above problems, this paper adopts a multivariate component data analysis method to process 14 mass fraction data elements, namely Ag, As, Au, Bi, Cu, Fe, Hg, Mn, Mo, Ni, Pb, Sb, W, and Zn, in the 1:50,000 soil geochemical data from the Duobaoshan area of Heilongjiang. The spatial distribution and internal structural characteristics of raw, logarithmic transformation and isometric logarithmic ratio (ILR) transformed data were compared using exploratory data analysis (EDA); robust principal component analysis (RPCA) was applied to obtain the PC1 and PC2 principal component combinations associated with mineralization, and a spectrum–area (S–A) fractal model was further used to decompose the geochemical anomalies of the PC1 and PC2 principal component combinations as composite anomalies. The results show the following: (i) The data transformed by the isometric logarithmic ratio (ILR) eliminate the influence of the original data closure effect, and the spatial scale of the data is more uniform; the data are approximately normally distributed, based on which RPCA can be applied to better explore the correlation between elements and the pattern of co-associated combinations. (ii) The S–A method was further used to decompose the composite anomalies of the PC1 and PC2 principal component combination in the study area. The anomalous and background fields of the screened-out PC1 and PC2 principal component combinations reflect anomalous information on mineralization dominated by Au mineralization. Moreover, the anomaly and background information after extraction were in good agreement with the known Au deposits (points), and many geochemical anomalies with prospecting potential were obtained in the periphery, providing a theoretical basis and exploration focus for the next step in the searching and exploring of the study area. Full article

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

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17 pages, 4179 KiB

Open AccessArticle

Genesis of the Dongpuzi Gold Deposit in the Liaodong Peninsula, NE China: Constraints from Geology, Fluid Inclusion, and C–H–O–S–Pb Isotopes

by Cong Chen, Taotao Wu, Deming Sha, Dongtao Li, Zhongzhu Yang, Jing Zhang and Qingqing Shang

Minerals 2022, 12(8), 1008; https://doi.org/10.3390/min12081008 - 11 Aug 2022

Cited by 2 | Viewed by 1210

Abstract

The Dongpuzi deposit is an epithermal gold deposit located in the southern margin of the Shaozihe volcanic fault basin in the Liaodong Peninsula. On the basis of fluid inclusion and C–H–O–S–Pb isotope data, a metallogenic model is established for the Dongpuzi deposit. The [...] Read more.

The Dongpuzi deposit is an epithermal gold deposit located in the southern margin of the Shaozihe volcanic fault basin in the Liaodong Peninsula. On the basis of fluid inclusion and C–H–O–S–Pb isotope data, a metallogenic model is established for the Dongpuzi deposit. The mineralization at the Dongpuzi deposit has experienced quartz–pyrite (I), quartz–sulfide (II), and quartz–calcite (III) stages. The quartz from ore stage II has liquid-dominated aqueous inclusions, which have homogenization temperatures ranging from 113 to 162 °C and salinities varying from 3.2 to 9.6 wt% NaCl equiv. The quartz from the quartz–calcite stage has decreasing homogenization temperatures (106~143 °C) and salinities (2.7~6.9 wt% NaCl equiv.). The fluid inclusion data indicate that the gold ores were precipitated from low-temperature and low-salinity solutions, with an obvious decrease in temperature and salinity from ore stages II to III. The calculated δ¹⁸O_water values for the quartz of ore stage II range from −14.71‰ to −13.31‰, and the corresponding δD_water values range from −103.3‰ to −96.1‰, indicating that the ore-forming fluids could be of a meteoric origin. The calcite from ore stage III has δ¹³C_V-PDB values of −4.5‰ to −4.2‰ and δ¹⁸O_V-SMOW values of +7.0‰ to +7.4‰, indicating a mantle source for the carbon. The pyrite yielded δ³⁴S values of +4.1‰ to +6.6‰ and Pb isotopes consistent with those of the host trachyte porphyry and volcanic rocks of the Xiaoling Formation, which suggests that the S and Pb in gold ores were dominantly derived from the host trachyte porphyry and volcanic rocks of the Xiaoling Formation, with some combination of Paleoproterozoic metamorphic rocks of the Gaixian Formation. These results, together with the ore geology, indicate that the Dongpuzi deposit is a typical low-sulfidation epithermal gold deposit with important ore-forming materials input from the host trachyte porphyry, volcanic rocks of the Xiaoling Formation, and Paleoproterozoic metamorphic rocks of the Gaixian Formation. The Dongpuzi deposit was formed under an extensional setting related to the Early Cretaceous lithospheric extension and thinning of the eastern North China Craton. Full article

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

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26 pages, 7421 KiB

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The Early Cretaceous Granitoids and Microgranular Mafic Enclaves of Sanguliu Pluton, the Liaodong Peninsula: Implications for Magma Mixing and Decratonic Gold Mineralization in the Eastern North China Craton

by Taotao Wu, Cong Chen, Dongtao Li, Yan Zhao, Chunqiang Zhao and Yongheng Zhou

Minerals 2022, 12(8), 1004; https://doi.org/10.3390/min12081004 - 09 Aug 2022

Cited by 1 | Viewed by 1452

Abstract

Some Early Cretaceous granitoids characterized by abundant mafic microgranular enclaves (MMEs) formed by magma mixing have been associated with gold deposits in the eastern North China Craton (NCC). However, the genetic connection of magma mixing with gold mineralization remains unclear. The zircon U–Pb [...] Read more.

Some Early Cretaceous granitoids characterized by abundant mafic microgranular enclaves (MMEs) formed by magma mixing have been associated with gold deposits in the eastern North China Craton (NCC). However, the genetic connection of magma mixing with gold mineralization remains unclear. The zircon U–Pb ages and in situ Lu-Hf isotopic compositions, whole-rock major- and trace-element and Sr–Nd–Pb isotopic compositions, as well as EPMA biotite compositions, were presented for the Sanguliu granodiorite and enclaves in the Liaodong Peninsula in order to obtain insights into the spatial and temporal distribution, and internal connection of magma mixing with the decratonic gold deposits in the eastern NCC. The Sanguliu granodiorite yielded coeval formation ages with the enclaves (~123 Ma), and their acicular apatites and plagioclase megacrysts suggest that the enclaves were formed by mixing between mafic and felsic magmas. Geochemically, the Sanguliu granodiorite is high-K calc-alkaline I-type granite, with an initial ⁸⁷Sr/⁸⁶Sr ratio of 0.70552 to 0.71470 and strongly negative ε_Nd(t) (−11.4 to −21.3) and zircon in situ ε_Hf(t) values (−15.1 to −25.4), indicating that the felsic magmas were ancient lower crust with the involvement of mantle-derived materials. Meanwhile, the enclaves have high MgO (4.18 to 6.17 wt.%), Cr (45.91 to 290.04 ppm), and Ni (19.65 to 88.18 ppm) contents, with high Mg^# values of 50 to 57 at intermediate SiO₂ contents (53.68 to 55.78 wt.%), highly negative ε_Nd(t) values (mostly −18.42 to −22.03), and in situ zircon ε_Hf(t) values (−18.6 to −22.7), indicating that the mafic magma was mainly derived from the enriched lithospheric mantle. Furthermore, the biotites from the Sanguliu granodiorite clustered between the MH and NNO buffers in the Fe²⁺–Fe³⁺–Mg diagram. This, combined with the high Ce/Ce* ratios (1.30 to 107.18) of the zircons, indicates that the primary magmas forming the Sanguliu granodiorite had a high oxygen fugacity, which is favorable for gold mineralization. These findings, together with previous studies of the Early Cretaceous granitoids with enclaves in the eastern NCC, suggest that magma mixing commonly occurred during 110–130 Ma and is temporally, spatially, and genetically related to decratonic gold systems in eastern NCC. Full article

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

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15 pages, 3588 KiB

Open AccessArticle

Ore Genesis of the Dongping Gold Deposit in the Northern Margin of North China Craton: Constraints from In-Situ Major, Trace Elemental Analysis of Magnetite and Pyrite

by Chengyang Wang, Jiajia Yu, Yunsheng Ren, Junkang Zhao and Zhenjun Sun

Minerals 2022, 12(8), 978; https://doi.org/10.3390/min12080978 - 31 Jul 2022

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Abstract

The Zhangxuan district in North China, also known as Northwestern Hebei “Golden Triangle,” develops many intrusion-hosted lode-gold deposits. The Dongping gold deposit in the Zhangxuan district is well known for its unique hosting of rocks and ore mineral assemblages. Magnetite and pyrite are [...] Read more.

The Zhangxuan district in North China, also known as Northwestern Hebei “Golden Triangle,” develops many intrusion-hosted lode-gold deposits. The Dongping gold deposit in the Zhangxuan district is well known for its unique hosting of rocks and ore mineral assemblages. Magnetite and pyrite are common minerals that widely exist in ores of the Dongping deposit. To get a better understanding of the evolution of the ore-forming fluids responsible for mineralization, we report on an integrated study on the electron microprobe analysis (EMPA) and laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) analysis of magnetite and pyrite from the deposit. The major results are as follows: The magnetite grains from the Dongping deposit show a variable content of major and trace elements such as Ti, Al, Si, Fe, Mn, Cr, Na, V, and Co, and the majority of the magnetite contain low Ti contents, revealing potential properties of hydrothermal magnetite. The flat time-resolved signals of LA-ICP-MS imply that the majority of trace elements in magnetite exist in the form of isomorphism, except for some incompatible trace elements. Magnetites from the Dongping deposit have compositional characteristics of hydrothermal origins, and the genetic discriminant diagrams of Ti–V, Ti–Ni/Cr or (Ca + Al + Mn)–(Ti + V) show that they may be originated from magma differentiated hydrothermal solutions. Co, Ni in pyrite from Dongping mainly enter the lattice via isomorphism, and Cu, Zn, Ag, W, Sn, Au, Pb, and Bi are partitioned into pyrite as micro/nano- mineral inclusions. The Co, Ni content, and the Ni/Co ratios, indicated that the temperature of the ore-forming fluids has decreased from Py-1 to Py-2, and the enrichment of Au in Py-2 may be related to the cooling and boiling of the fluids. Full article

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

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13 pages, 3539 KiB

Open AccessArticle

Paleoproterozoic Mineralization of the Lijiapuzi Gold Deposit in the Liaodong Peninsula, NE China: Constraints from ⁴⁰Ar-³⁹Ar Age, S-Pb Isotopes, and In Situ Analyses

by Yan Zhao, Peng Zhang, Hongzhi Yang, Linlin Kou, Zhongwei Bi, Zhongzhu Yang and Jiang Chen

Minerals 2022, 12(8), 971; https://doi.org/10.3390/min12080971 - 29 Jul 2022

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Abstract

A Paleoproterozoic ⁴⁰Ar/³⁹Ar age, interpreted as the gold metallogenic epoch of the Lijiapuzi deposit in NE China, is reported in this paper. The ore body of this deposit is hosted in the marbles and schists of the Paleoproterozoic Dashiqiao Formation [...] Read more.

A Paleoproterozoic ⁴⁰Ar/³⁹Ar age, interpreted as the gold metallogenic epoch of the Lijiapuzi deposit in NE China, is reported in this paper. The ore body of this deposit is hosted in the marbles and schists of the Paleoproterozoic Dashiqiao Formation and exhibits parallel development to the foliation of the country rocks. Coexisting auriferous pyrite and tremolite can be observed both in the field and under a microscope, revealing the presence of hydrothermal activity in the deposit. The δ³⁴S composition of the auriferous pyrite varies from +8‰ to +12.3‰, indicating a sedimentary origin. The auriferous pyrite and host marble have similar Pb isotopic ratios, indicating the contribution of Paleoproterozoic sediments to gold mineralization. Furthermore, in situ S and trace element analyses of the auriferous pyrite reveal that the main gold mineralization stage was Py2, which coexists with radial tremolite. ⁴⁰Ar/³⁹Ar dating of these tremolite samples yields a plateau age of ~1851.23 Ma, with similar isochronal and inverse isochronal ages. The Paleoproterozoic gold metallogenesis, together with the contemporary Pb-Zn, boron, graphite, and magnetite mineralization, constitute an important mineralogenetic series during the evolution of the Jiao-Liao-Ji orogeny in the Liaodong Peninsula. Full article

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

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28 pages, 8034 KiB

Open AccessArticle

Two Epochs of Mineralization of Orogenic Gold Deposit in the East Kunlun Orogenic Belt: Constraints from Monazite U–Pb Age, In Situ Sulfide Trace Elements and Sulfur Isotopes in Wulonggou Gold Field

by Zheming Zhang, Qingdong Zeng, Tong Pan, Hailin Xie, Zhanhao Wei, Hongrui Fan, Jinjian Wu, Kuifeng Yang, Xinghui Li and Gaizhong Liang

Minerals 2022, 12(8), 968; https://doi.org/10.3390/min12080968 - 29 Jul 2022

Cited by 3 | Viewed by 1609

Abstract

The Wulonggou Gold Field is one of the giant gold fields in the East Kunlun Orogenic Belt, northwestern China. Previous studies mainly focused on elementary mineral isotopic studies, fluid inclusions, and geological features in the Wulonggou Gold Field. In this study, we report [...] Read more.

The Wulonggou Gold Field is one of the giant gold fields in the East Kunlun Orogenic Belt, northwestern China. Previous studies mainly focused on elementary mineral isotopic studies, fluid inclusions, and geological features in the Wulonggou Gold Field. In this study, we report some research on the precise age and the specific ore-forming process of the WGF: the hydrothermal monazite U–Pb ages; the way of gold precipitation; the composition, evolution, and source of ore-forming fluids of the Wulonggou Gold Field. Finally, we demonstrate a link between two-stage hydrothermal events and sequential episodes of crust-derived magmas, with implications for gold metallogeny in the East Kunlun Orogenic Belt. There are four hydrothermal stages that are recognized: a quartz–pyrite stage (stage 1), a quartz–pyrite–arsenopyrite–chalcopyrite stage (stage 2), a quartz–galena–sphalerite–pyrite stage (stage 3) and a quartz–stibnite–carbonate stage (stage 4). The monazite U–Pb ages of the Huanglonggou and Hongqigou deposits in the Wulonggou Gold Field were 422.2 ± 2.4 Ma and 236.7 ± 3.7 Ma, respectively, which support the opinion of two epochs of mineralization. Stages 1 and 2 are the main gold mineralization stages, wherein Au and As have a close genetic relationship. The Hongqigou and Huanglonggou deposits seem to have been formed in different metallogenic events due to the contrast on the trace element compositions in pyrite. The sources of the ore-forming materials and fluids of the Hongqigou and Huanglonggou deposits show apparent characteristics of orogenic gold deposit, and the magmatic events during Paleozoic and Mesozoic have an important contribution to the formation of the gold deposits. The gold deposits in the Wulonggou Gold Field can be interpreted as an orogenic gold system related to two-epoch tectonic–magmatic events. Full article

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

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22 pages, 5221 KiB

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Ore Genesis of the Toudaochuan Gold Deposit in Central Jilin Province, NE China: Constraints from Fluid Inclusions and C–H–O–S–Pb Isotopes

by Jingmou Li, Yunsheng Ren, Qun Yang and Xinhao Sun

Minerals 2022, 12(8), 964; https://doi.org/10.3390/min12080964 - 29 Jul 2022

Cited by 1 | Viewed by 1466

Abstract

The Toudaochuan gold deposit is a recently discovered lode gold deposit in Central Jilin Province. Gold ore bodies are dominantly controlled by NE-trending fault. The major hydrothermal period can be further divided into the quartz–pyrite stage (stage I), quartz–gold–polymetallic sulfides stage (stage II, [...] Read more.

The Toudaochuan gold deposit is a recently discovered lode gold deposit in Central Jilin Province. Gold ore bodies are dominantly controlled by NE-trending fault. The major hydrothermal period can be further divided into the quartz–pyrite stage (stage I), quartz–gold–polymetallic sulfides stage (stage II, major gold mineralization stage), and quartz–carbonate stage (stage III). Primary fluid inclusions (FIs) identified in quartz at different hydrothermal stages include liquid-rich aqueous FIs (L-type), CO₂ FIs (C-type, including CO₂-bearing C1-type FIs and CO₂-rich C2-type FIs), and minor vapor-rich aqueous FIs (V-type). Microthermometry studies on different fluid inclusions indicate that the original ore-forming fluids belonged to the CO₂–H₂O–NaCl system characterized by a moderate–low temperature and low salinity in stages I and II, and they finally evolved into a H₂O–NaCl system characterized by low temperature and low salinity in stage III. Fluid immiscibility is considered to be the key ore-forming mechanism. The initial ore-forming fluid was originated from magmatic water and was mixed with meteoric water in the later stage. The S and Pb isotope data suggest that the ore metal materials were derived from the mixed source of mantle and crust. Based on all the above data, therefore, it can be proposed that the Toudaochuan gold deposit is a mesothermal magmatic–hydrothermal gold deposit. Full article

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

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18 pages, 5100 KiB

Open AccessArticle

Age of the Tuchengzi Formation in Western Liaoning Province and the Jurassic–Cretaceous Boundary from the Continuous Core Records of Well YD1, Jinyang Basin

by Shou-Liang Sun, Shu-Wang Chen, Zhong-Jie Yang, Tao Zhang, Yong-Fei Li, Ji-Chang Zhu, Huai-Chun Wu, Tian-Tian Wang, Yue-Juan Zheng and Qiu-Hong Ding

Minerals 2022, 12(8), 953; https://doi.org/10.3390/min12080953 - 28 Jul 2022

Cited by 2 | Viewed by 1611

Abstract

The Tuchengzi Formation is widely distributed in western Liaoning Province with a clear top and bottom. It is the focal area for the delineation of the terrestrial Jurassic–Cretaceous boundary in China. Based on continuous core samples taken from well YD1, detailed lithostratigraphic sequences [...] Read more.

The Tuchengzi Formation is widely distributed in western Liaoning Province with a clear top and bottom. It is the focal area for the delineation of the terrestrial Jurassic–Cretaceous boundary in China. Based on continuous core samples taken from well YD1, detailed lithostratigraphic sequences and zircon uranium–lead (U-Pb) dating WERE used to investigate the Tuchengzi Formation. The zircon U-Pb ages of the tuff samples taken from the First and Third Members of the Tuchengzi Formation ranged from 153.8 to 137.16 Ma, indicating that they were formed in the late Middle Jurassic–Early Cretaceous. Dating results from the bottom of the Second Member of the Tuchengzi Formation indicate that the sedimentary time of the stratum is no later than 145.7 ± 2.1 Ma. We concluded that the Jurassic–Cretaceous boundary of the Jinyang Basin in western Liaoning province may be located at the interface at a depth of 464 m in well YD1. This conclusion is consistent with the Jurassic–Cretaceous boundary that has been presumed by other researchers based on paleontological assemblage features found in recent years, and can provide useful geological marker beds for the future study of the terrestrial Jurassic–Cretaceous boundary. In addition, the authors also systematically sorted the potential development areas and layers of the terrestrial Jurassic–Cretaceous boundary line, which may also provide useful geological marker beds for the future study of the terrestrial Jurassic–Cretaceous boundary. Full article

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

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Open AccessArticle

Petrogenesis and Tectonic Implications of the Ore-Associated Intrusions in Bayanbaolege Ag Polymetallic Deposit, Inner Mongolia, NE China

by Xi Wang, Qun Yang, Zhen-Ming Sun and Yun-Sheng Ren

Minerals 2022, 12(7), 912; https://doi.org/10.3390/min12070912 - 20 Jul 2022

Cited by 2 | Viewed by 1158

Abstract

The large Bayanbaolege Ag polymetallic ore deposit is located in the Tuquan-Linxi Fe (Sn)-Cu-Pb-Zn-Ag-Nb (Ta) polymetallic metallogenic belt, which is an important part of the Great Xing’an Range metallogenic province, northeast China. The sulfide–quartz vein-type orebodies in the deposit are mainly hosted in [...] Read more.

The large Bayanbaolege Ag polymetallic ore deposit is located in the Tuquan-Linxi Fe (Sn)-Cu-Pb-Zn-Ag-Nb (Ta) polymetallic metallogenic belt, which is an important part of the Great Xing’an Range metallogenic province, northeast China. The sulfide–quartz vein-type orebodies in the deposit are mainly hosted in the Cretaceous granodiorite porphyry and Late Permian Linxi formation. The U-Pb dating of the zircon from the post-ore diorite porphyrite yields an age of 124.8 ± 1.1 Ma, which constrains the mineralization time at the Early Cretaceous. The Sr-Nd isotope values (⁸⁷Sr/⁸⁶Sr)_i = 0.708576~0.710536; ε_Nd (t) = −0.51~+0.69; the Hf isotope values ¹⁷⁶Hf/¹⁷⁷Hf = 0.2827278~0.2830095, the ε_Hf (t) = +3.1~+11.2, T_DM2 = 615~1341 Ma of the metallogenic granodiorite porphyry. The Hf isotope values ¹⁷⁶Hf/¹⁷⁷Hf = 0.2828596~0.2829451, and the ε_Hf (t) = +5.7~+8.8 of the diorite porphyrite, T_DM2 = 827~1108 Ma, indicating that the ore-forming materials were the possible involvement of heterogeneous juvenile sources including moderately depleted mantle and newly underplated lower crust. The major and trace elements (including REEs) implied that these intrusions are the I-type granite and linked intimately to the westward subduction of the Paleo-Pacific Ocean plate. From these whole-rock major and trace elements and zircon U-Pb ages, as well as Sr-Nd-Hf isotope data, we conclude that the ore-associated I-type granites in the Bayanbaolege deposit formed in an extensional tectonic setting of the Early Cretaceous, and are compactly related to the retreat of the Paleo-Pacific Ocean subducted plate linked intimately to the westward subduction of the Paleo-Pacific Ocean plate rather than the closure of the Mongol–Okhotsk Ocean. Furthermore, by integrating geological background work and previous research work, implying the mineralization age of the Bayanbaolege deposit should have been formed in the 125–130 Ma. Full article

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

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