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1
Bushuev, Yackov Yur’evich, and Vasilii Ivanovich Leontev. "The Geochemical Features of Epithermal Gold-Telluride (Au-Te) Ores of the Podgolechnoe Deposit (Central Aldan Ore District, Yakutia)." Key Engineering Materials 743 (July 2017): 422–25. http://dx.doi.org/10.4028/www.scientific.net/kem.743.422.
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The Central Aldan ore district is a geologically unique area, representing the conjunction zone of the ancient structures of the Archean–Proterozoic crystalline shield, overlain by the Vendian–Cambrian sedimentary cover. The latter was formed in the Mesozoic by intensive alkaline magmatism. Within the Central Aldan ore district, most of primary gold-ore deposits are confined to the sedimentary cover. Until recently it was considered that only ancient complexes in the crystalline basement contain commercial Au-U mineralization. As a result of the geological exploration works over the period of 2003–2006, the Podgolechnoe deposit was discovered. Gold mineralization in this deposit occurs both in rocks of sedimentary cover and crystalline basement. Ore bodies in rocks of the crystalline basement (A-type alkaline deposits) contain epithermal gold-telluride (Au-Te) mineralization, which is new for Central Aldan ore district. This work presents results of the study of geochemical composition of the Podgolechnoe deposit ores and their comparison with typical epithermal gold-ore deposits. In total, 15 samples were studied. The homogeneity of the sample collection, the correlation between Au and other elements, the enrichment coefficients of elements-admixtures, and the REE distribution were analyzed. It was established that gold ores of the Podgolechnoe deposit are geochemically heterogeneous, but, in general, they correspond to the geochemical spectrum characteristic of the gold ores of A-type epithermal deposits. In contrast to Au-U deposits, common in the studied area, ores of the Podgolechnoe deposit show no correlation between gold and uranium.
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Su, Zhi-Kun, Xin-Fu Zhao, Xiao-Chun Li, Mei-Fu Zhou, Allen K. Kennedy, Jian-Wei Zi, Carl Spandler, and Yue-Heng Yang. "UNRAVELING MINERALIZATION AND MULTISTAGE HYDROTHERMAL OVERPRINTING HISTORIES BY INTEGRATED IN SITU U-Pb AND Sm-Nd ISOTOPES IN A PALEOPROTEROZOIC BRECCIA-HOSTED IOCG DEPOSIT, SW CHINA." Economic Geology 116, no. 7 (November 1, 2021): 1687–710. http://dx.doi.org/10.5382/econgeo.4840.
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Abstract Precambrian iron oxide copper-gold (IOCG) deposits are generally encountered with multistage hydrothermal overprints and hence have complex isotopic records. Precise dating of ore-forming and overprinting events and assessment of time-resolved metal sources are fundamental for understanding ore genesis. Here, we quantify the evolution history by integrating in situ U-Pb dating of texturally constrained allanite and Sm-Nd isotope data of ores and major rare earth element (REE) minerals in the breccia-hosted Lanniping Fe-Cu deposit in Kangdian region, southwestern China. The economically mineralized breccia in Lanniping Fe-Cu deposit is characterized by pervasive and texturally destructive replacement of polymictic clasts, including host metasedimentary packages, the intruded dolerite, and pre-ore halokinetic breccia. Ore minerals in cements are mainly composed of magnetite, chalcopyrite, bornite, and variable amounts of REE-rich minerals (e.g., apatite and allanite/epidote). Two types of allanite were identified in ores. Type I prismatic allanite texturally intergrown with magnetite has a SHRIMP U-Pb age of 1728 ± 20 Ma (1σ), which matches a zircon U-Pb age of 1713 ± 14 Ma (2σ) for the dolerite clasts and provides the direct age constraint on the Fe-Cu mineralization event. Type II anhedral allanite shows complex zoning and is spatially associated with, but texturally later than, magnetite, apatite, and chalcopyrite. This type of allanite yields significantly younger SHRIMP dates of 1015 ± 33 (1σ) and 800 ± 16 Ma (1σ) for cores and rims, respectively, which correspond to discrete regional magmatic events and hence record hydrothermal overprint/remobilization events of ore minerals in the deposit. Integrated Sm-Nd isotope compositions of type I allanite, apatite, and whole ores generally align along the reference Sm-Nd isochron of 1728 Ma, further confirming the primary ore formation at ~1.7 Ga. Corresponding εNd(1728 Ma) values ranging from –2.8 to 0.3 are significantly higher than those of the host metasedimentary rocks (–9.5 to –6.2) but comparable to those of contemporaneous igneous intrusions (–0.3 to 5.3) in the region, demonstrating that REE components of the primary ores were dominantly sourced from rocks of mantle-derived affinity. Both cores and rims of the younger type II allanite grains have Nd isotope compositions consistent with the unique time-evolved line of the ~1.7 Ga ores, implying that REEs incorporated into type II allanite were ultimately sourced from the primary ores in this deposit. The combined texture, chemical, U-Pb, and Sm-Nd isotope data thus demonstrate that REE remobilization was localized during post-ore hydrothermal overprint with negligible external inputs of REEs to the primary ores in the Lanniping deposit. In this contribution, we not only date primary ore formation but also recognize several younger allanite generations that record internal metal redistributions in response to post-ore tectonothermal events. Our study highlights the potential of ore-associated REE minerals such as allanite for resolving the age of multiple stages of hydrothermal events in complex ore deposits by ion probe, provided that careful examination of textural and paragenetic relationship of ores is conducted. Our finding of these younger allanite generations also exemplifies the significance of evaluation on time-resolved metal input for better characterizing the evolution history of the IOCG deposits.
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Gongalsky, B. "Deposits of the Udokan-Chineysky ore-magmatic system of Eastern Siberia." IOP Conference Series: Earth and Environmental Science 962, no. 1 (January 1, 2022): 012051. http://dx.doi.org/10.1088/1755-1315/962/1/012051.
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Abstract The aggregate of ore deposits localized in the Udokan-Chineysky ore district is unique and is the result of multi–stage, polygenetic formation. The deposits of copper and other metals formed at various depths occur within a limited area. The oxide and sulfide ore are spatially associated in the sedimentary rocks pertaining to the Paleoproterozoic Udokan Supergroup and the intrusive mafic–ultramafic rocks of the Chineysky Complex. The granite rocks of the Kodar Complex and gabbro rocks of the Chineysky Complex also date back to Paleoproterozoic. The same age has been established for metasomatic Nb–Ta–Zr–REE–Y and U mineralization in the albitized terrigenous rocks of the Udokan Supergroup (Katugin deposit and Chitkanda prospect) and U–Pd prospects hosted in terrigenous rocks. The U–REE mineralization superposed on the titanomagnetite deposits in the Chineysky pluton has not analogues in the world’s practice. The occurrences of uranium mineralization have been noted in form of pitchblende and U–Th rims around chalcopyrite grains at the Unkur copper deposit hosted in sedimentary rocks. The enrichment in U and Pb has been documented in crosscutting quartz veinlets with bornite mineralization at the Udokan deposit.
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Qiu, Lin-Fei, Yu Wu, Qiong Wang, Lin-Feng Wu, Zhong-Bo He, Song Peng, and Yun-Fei Fan. "Metallogenic Mechanism of Typical Carbonate-Hosted Uranium Deposits in Guizhou (China)." Minerals 12, no. 5 (May 6, 2022): 585. http://dx.doi.org/10.3390/min12050585.
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Research on topics such as geological–tectonic evolution, metallogenic models of deposits (gold, mercury, lead, zinc, etc.), and ore-forming fluids’ evolution has been conducted in Guizhou. However, few studies have been conducted on uranium (U) deposits (especially carbonate-hosted U deposits). Moreover, the relationship between hydrocarbon fluids and U-mineralization has not been addressed at all. Typical carbonate-hosted U deposits (including some ore spots) in Guizhou Province have been investigated through close field work, petrography, mineralogical, micro-spectroscopy, organic geochemical and C isotope studies. The central part of the U-ore body is often black (the black alternation zone) at the outcrop, and its sides are gray and gray-brown (the gray alternation zone); the color gradually becomes lighter (black to gray) from the center of the ore body out to the sides. Petrographic observations, microscopic laser Raman spectroscopy, and infrared spectroscopic and scanning electron microscope analyses have indicated that U-minerals (pitchblende and coffinite), pyrite and “black” organic matter (OM) are closely co-dependent, with the OM having the typical characteristics of bitumen. Large light oil fluid inclusions were found in gray alternation rocks (besides the U-ore body) with strong light blue fluorescence properties, indicating that hydrocarbon fluids and U-minerals may came from the same U-bearing hydrocarbon fluids. The values of the 13C isotope value, a biomarker of OM and trace elements, REEs in U-ores, were found to be similar here to those in the local paleo-petroleum reservoir, indicating that the bitumen may originate from the deeply intruding paleo-petroleum reservoir. The precipitation of U is related to the cracking differentiation of hydrocarbon fluids. As result, the carbonate-hosted U-mineralization in Guizhou is neither of a sedimentary diagenesis type, nor of a sedimentary diagenesis superimposed leaching hydrothermal transformation type, as have been described by previous scholars. To be exact, the U deposit is controlled by fault and hydrocarbon fluids, and so it can be defined as a structural hydrocarbon–carbonate-type U deposit. A new U-mineralization model was proposed in this study. Here, U, molybdenum, and other metals were mainly found in the black rocks in the lower stratum (presumably Niutitang Formation), having migrated together with hydrocarbon fluids in the form of tiny mineral inclusions. The hydrocarbon fluids (containing some brine) caused cracking and differentiation upon entering the fracture zone, at which point the ore-forming materials (U, pyrite, and other metals) were released and precipitated.
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Golubev, V. N., N. N. Tarasov, I. V. Chernyshev, A. V. Chugaev, G. V. Ochirova, and B. T. Kochkin. "Post-Ore Processes of Uranium Migration in the Sandstone-Hosted Type Deposits: 234U/238U, 238U/235U and U–Pb Systematics of Ores of the Namaru Deposit, Vitim District, Northern Transbaikalia." Geology of Ore Deposits 63, no. 4 (July 2021): 287–99. http://dx.doi.org/10.1134/s1075701521040024.
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Abstract To assess the nature of the post-ore behaviour of uranium in the Namaru deposit (Khiagda ore field), U–Pb isotope systems and the isotopic composition of uranium (234U/238U and 238U/235U) were studied. The studied samples represent different ore zones of the deposit and were collected along cross-sections both vertically and horizontally. Wide variations in the isotopic composition of uranium and U–Pb isotopic age have been established. Deviations of the 234U/238U ratio from equilibrium values, which for some samples exceed 50%, along with significant variations in the isotopic age, indicate that permafrost layer, which covered the catchment areas of paleovalleys with meteoric oxygen-containing waters ca. 2.5 Ma ago, did not lead to preserving uranium ores at the deposit. Uranium migration took place during the Quaternary period. The effective combining the U–Pb dating and 234U/238U data in assessing the post-ore redistribution of uranium made it possible to recognize: removal of uranium from some zones of the ore body and its accompanying redeposition in others. Wide variations in the 238U/235U (137.484–137.851) ratios throughout the entire studied cross-sections can be explained by the different locations of samples relatively to the ore deposition front and change in redox conditions as this front advanced. Depletion of the light isotope 235U in the lower zone of the ore body may be associated with the influence of ascending carbonic waters established in the regional basement. The effect of such waters on uranium-bearing rocks causes predominant leaching of light 235U.
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Jiang, Hongjun, Chunsi Yang, Dequan Wang, Hui Zheng, Jie Li, and Huayong Chen. "Multiple-Stage Mineralization in the Huayangchuan U−REE−Mo−Cu−Fe Ore Belt of the Qinling Orogen, Central China: Geological and Re−Os Geochronological Constraints." Journal of Earth Science 33, no. 1 (February 2022): 193–204. http://dx.doi.org/10.1007/s12583-021-1557-1.
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AbstractThe Huayangchuan ore belt is located in the western segment of Xiaoqinling Orogen in the southern margin of the North China Craton (NCC), and hosts voluminous magmatism and significant U−REE−Mo−Cu−Fe polymetallic mineralization. However, geochronological framework of the various mineralization phases in this region is poorly understood. Here, we present new Re−Os isochron ages on magnetite from the Caotan Fe deposit (2 675 ± 410 Ma, MSWD = 0.55), and on pyrite from the Jialu REE deposit (2 127 ± 280 Ma, MSWD = 1.9) and Yuejiawa Cu deposit (418 ± 23 Ma, MSWD = 11.5), and Re−Os weighted average model age on pyrite from the Taoyuan Mo−U deposit (235 ± 14 Ma, MSWD = 0.17). These ages, combined with regional geology and mineralization ages from other deposits, suggest that mineralization in the Huayangchuan ore belt lasted from the Neoarchean to the Late Mesozoic. The mineralization corresponds to regional tectono-magmatic events, including the Neoar-chean alkali magmatism (REE mineralization), Paleoproterozoic plagioclase-amphibolite emplacement (Fe mineralization), Paleoproterozoic pegmatite magmatism (U mineralization), Paleozoic Shangdan oceanic slab subduction-related arc magmatism (Cu mineralization), Early Mesozoic Paleo-Tethys Ocean subduction-related arc magmatism (Mo−U mineralization), and Late Mesozoic Paleo-Pacific oceanic plate subduction direction change-related Mo(-Pb) mineralization. We proposed that the Huayang-chuan ore belt has undergone prolonged metallogenic evolution, and the magmatism and associated mineralization were controlled by regional geodynamic events.
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Li, Li, Hai-Li Li, Guo-Guang Wang, and Jian-Dong Sun. "Geochronology of the Baishi W-Cu Deposit in Jiangxi Province and Its Geological Significance." Minerals 12, no. 11 (October 30, 2022): 1387. http://dx.doi.org/10.3390/min12111387.
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The Baishi W-Cu deposit is located in the Nanling metallogenic belt, which is famous for its numerous W deposits and reserves. The formation age of this deposit remains unclear. In order to further infer the formation age of the deposit, this study conducted detailed LA-ICP-MS U-Pb isotopic analyses of zircon and monazite selected from ore-related Baishi granite. The LA-ICP-MS zircon U-Pb weighted average ages of Baishi granite were determined to be 223 ± 2 Ma and 226 ± 1 Ma, and the LA-ICP-MS U-Pb weighted average ages of monazite were determined to be 224 ± 2 Ma and 223 ± 1 Ma. The BSE image of monazite was homogeneous, and the pattern of rare earth elements had an obvious negative Eu anomaly, indicating that monazite was of magmatic origin. Combining the ages of zircon and monazite, this study inferred that Baishi granite and the Baishi W-Cu deposit formed in the Triassic. The determination of the ore-forming event of the Baishi W-Cu deposit provides new data regarding the important Indosinian (Triassic) mineralization events in the Nanling metallogenic belt and suggests that geologists should strengthen the prospecting work of Indosinian tungsten deposits in the Nanling area. In terms of tectonic setting, it was inferred that the Triassic Baishi W-Cu deposit was formed in the extensional environment after intracontinental orogeny.
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Wang, Yongjian, Honghai Fan, Yaqing Pang, and Wei Xiao. "Geochemical Characteristics of Chlorite in Xiangshan Uranium Ore Field, South China and Its Exploration Implication." Minerals 12, no. 6 (May 30, 2022): 693. http://dx.doi.org/10.3390/min12060693.
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Chlorite is one of the most important hydrothermal minerals in many hydrothermal uranium deposits worldwide and is commonly closely associated with the uranium mineralization. Trace elements in chlorite have been extensively applied to fingerprinting the hydrothermal fluid evolution and indicating the concealed ore bodies in porphyry Cu (-Au) deposits and skarn-related Pb-Zn deposits. However, this approach was rarely attempted on hydrothermal uranium deposits to date. Xiangshan uranium ore field, located in the southeast part of Gan-Hang Metallogenic (or Volcanic) Belt (GHMB), is the largest volcanic-related ore field in the whole country. In this study, the focus was placed on the petrographic characteristics and trace elements in hydrothermal chlorite from two typical deposits (Zoujiashan and Yunji) at Xiangshan. Four types of chlorites were identified, i.e., Chl1-Y and Chl2 from Yunji deposit, and Chl1-Z and Chl3 from Zoujiashan deposit. The pre-ore Chl1-Y and Chl1-Z are formed through replacing the original magmatic biotite. Chl2 and Chl3 occur as veinlets or disseminated, and are closely associated with early-ore U mineralization and main-ore U mineralization, respectively. All the four types of chlorites are typically trioctahedral chlorite. Vein-type/disseminated Chl2 and Chl3 in ore veins were precipitated directly from the hydrothermal fluids through dissolution-migration-precipitation mechanism, whereas the replacement-type chlorite was formed by the dissolution–crystallization mechanism. Empirical geothermometry indicates that the chlorite from Yunji and Zoujiashan were crystallized at 179~277 °C, indicating a mesothermal-epithermal precipitation environment. EPMA and LA-ICP-MS results show that the replacement-type chlorite has relatively consistent compositions at Yunji and Zoujiashan. Both Chl2 and Chl3 are enriched in U, Th but depleted in Mn and Ti. Compared with the Chl2 related to early-ore U mineralization, Chl3 that formed at main-ore stage has higher concentrations of Fe, U, Th, REEs, Mn and Ti, as well as higer Fe/(Fe + Mg) ratios. Such compositional differences between Chl2 and Chl3 are mainly attributed to the formation temperatures and fluid compositions/natures. Combined with petrology and chemical compositions of different types of chlorite, we propose that the presence of vein-type/disseminated chlorite with high U and Fe/(Fe + Mg) ratio but relatively low Mn, Ti and Pb contents can be regarded as an effective vector toward the most economic (high U grade) mineralized zone, whereas the occurrence of Chl2 is likely to indicate the subeconomic U mineralization and less potential exploration for uranium at depth.
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Fan, Gao-Hua, Jian-Wei Li, Xiao-Dong Deng, Wen-Sheng Gao, and Si-Yuan Li. "Age and Origin of the Dongping Au-Te Deposit in the North China Craton Revisited: Evidence from Paragenesis, Geochemistry, and In Situ U-Pb Geochronology of Garnet." Economic Geology 116, no. 4 (June 1, 2021): 963–85. http://dx.doi.org/10.5382/econgeo.4810.
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Abstract Dongping is the largest Au-Te vein deposit (~120 t Au) in the North China craton, but its age, origin, and setting remain unsolved. Here, we integrate paragenesis, geochemistry, and in situ U-Pb geochronology of garnet to constrain the timing and possible origin of the Dongping Au-Te deposit. Gold mineralization at Dongping is hosted in the Shuiquangou alkaline complex (ca. 401–390 Ma) and dominated by quartz-sulfide veins with minor ores in adjacent alteration envelopes. Andradite to grossular garnets are recognized in pre-, syn-, and post-ore quartz veins as well as mineralized alteration envelopes and are closely associated with a variety of ore and gangue minerals, mainly including K-feldspar, quartz, specularite, magnetite, pyrite, tellurides, epidote, and calcite. The paragenetic, textural, fluid inclusion, and compositional data suggest that garnets precipitated directly from a low-salinity fluid at 302° to 383°C and 90 to 330 bar. Garnets from various veins and alteration envelopes have similar U contents ranging from 0.80 to 13.89 mg/kg and yield reproducible U-Pb dates of 142 ± 5 to 139 ± 6 Ma (1σ) by laser ablation-inductively coupled plasmamass spectrometry. The dating results suggest that gold mineralization at Dongping occurred in the Early Cretaceous and thus preclude a genetic link between Au-Te mineralization and the ore-hosting alkaline intrusion as commonly suggested. When combined with independent geologic, geochemical, and geochronological studies, the new garnet U-Pb dates allow us to classify the Dongping Au-Te deposit as an oxidized intrusion-related gold deposit, with the causative magma likely derived from melting of an ancient enriched lithospheric mantle source due to destruction of the subcontinental lithospheric keel beneath the North China craton—a catastrophic event induced by the westward subduction of the Paleo-Pacific plate. This study highlights garnet U-Pb dating as a potential robust geochronometer for gold vein deposits elsewhere.
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Courtney-Davies, Liam, Cristiana L. Ciobanu, Simon R. Tapster, Nigel J. Cook, Kathy Ehrig, James L. Crowley, Max R. Verdugo-Ihl, Benjamin P. Wade, and Daniel J. Condon. "OPENING THE MAGMATIC-HYDROTHERMAL WINDOW: HIGH-PRECISION U-Pb GEOCHRONOLOGY OF THE MESOPROTEROZOIC OLYMPIC DAM Cu-U-Au-Ag DEPOSIT, SOUTH AUSTRALIA." Economic Geology 115, no. 8 (August 27, 2020): 1855–70. http://dx.doi.org/10.5382/econgeo.4772.
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Abstract Establishing timescales for iron oxide copper-gold (IOCG) deposit formation and the temporal relationships between ores and the magmatic rocks from which hydrothermal, metal-rich fluids are sourced is often dependent on low-precision data, particularly for deposits that formed during the Proterozoic. Unlike accessory minerals routinely used to track hydrothermal mineralization, iron oxides are dominant components of IOCG systems and are therefore pivotal to understanding deposit evolution. The presence of ubiquitous, magmatic-hydrothermal U-(Pb)-W-Sn-Mo–bearing zoned hematite resolves a range of geochronological issues concerning formation of the ~1.6 Ga Olympic Dam IOCG deposit, South Australia, at up to ~0.05% precision (207Pb/206Pb weighted mean; 2σ) using isotope dilution-thermal ionization mass spectrometry (ID-TIMS). Coupled with chemical abrasion-ID-TIMS zircon dates from host granite and volcanic rocks within and enclosing the ore-body, a confident magmatic-hydrothermal chronology is defined. The youngest zircon date from the granite intrusion hosting Olympic Dam indicates magmatism was occurring up until 1593.28 ± 0.26 Ma. The orebody was principally formed during a major mineralizing event following granite uplift and during cupola collapse, whereby the hematite with the oldest age is recorded in the outer shell of the deposit at 1591.27 ± 0.89 Ma, ~2 m.y. later than the youngest documented magmatic zircon. Hematite dates captured throughout major lithologies, different ore zones, and the ~2-km vertical extent of the deposit support ~2 m.y. of hydrothermal activity. New age constraints on the spatial-temporal evolution of the formation of Olympic Dam are considered with respect to a mantle to crustal continuum model. Cyclical tapping of magma reservoirs to maintain crystal mushes for extended time periods and incremental building of batholiths on the million-year scale prior to main mineralization pulses can explain the ~2-m.y. temporal window temporal window inferred from the data. Despite the challenge of reconciling such an extended window with contemporary models for porphyry deposits (≤1 m.y.), formation of Proterozoic ore deposits has been addressed at high-precision and supports the case that giant IOCG deposits may form over millions of years.
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MOISEENKO, NATALIA VALENTINOVNA. "U AND TH IN METASOMATITE OF POKROVKA GOLD DEPOSIT (THE AMUR REGION)." Messenger AmSU, no. 91 (2020): 80–84. http://dx.doi.org/10.22250/jasu.13.
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Data on the content of radioactive elements in the metasomatites of the Pokrovskoe gold ore deposit were obtained. It was found that U and Th are scattered in gold-bearing metasomatites. According to the results of the correlation analysis, a positive and negative correlation of U and Th with rare, rare-earth and ore elements in the metasomatites of the deposit was established.
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Yakubovich, Olga, Mary Podolskaya, Ilya Vikentyev, Elena Fokina, and Alexander Kotov. "U-Th-He Geochronology of Pyrite from the Uzelga VMS Deposit (South Urals)—New Perspectives for Direct Dating of the Ore-Forming Processes." Minerals 10, no. 7 (July 16, 2020): 629. http://dx.doi.org/10.3390/min10070629.
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We report on the application of the U-Th-He method for the direct dating of pyrite and provide an original methodological approach for measurement of U, Th and He in single grains without loss of parent nuclides during thermal extraction of He. The U-Th-He age of ten samples of high-crystalline stoichiometric pyrite from unoxidized massive ores of the Uzelga volcanogenic massive sulfide (VMS) deposit, South Urals, is 382 ± 12 Ma (2σ) (U concentrations ~1–5 ppm; 4He ~10−4 cm3 STP g−1). This age is consistent with independent (biostratigraphic) estimations of the age of ore formation (ca, 389–380 Ma) and is remarkably older than the probable age of the regional prehnite-pumpellyite facies metamorphism (~340–345 Ma). Our results indicate that the U-Th-He dating of ~1 mg weight pyrite sample is possible and open new perspectives for the dating of ore deposits. The relative simplicity of U-Th-He dating in comparison with other geochronological methods makes this approach interesting for further application.
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Gao, Hongchang, Fengyue Sun, Bile Li, Ye Qian, Li Wang, and Yajing Zhang. "Geochronological and Geochemical Constraints on the Origin of the Hutouya Polymetallic Skarn Deposit in the East Kunlun Orogenic Belt, NW China." Minerals 10, no. 12 (December 18, 2020): 1136. http://dx.doi.org/10.3390/min10121136.
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The Hutouya polymetallic skarn deposit lies in the Qimantagh area of the East Kunlun Orogenic Belt, NW China. Skarnization and mineralization at the deposit are closely associated with contemporary felsic intrusions. In this paper, zircon U-Pb ages and zircon Hf isotope as well as whole-rock geochemical and whole-rock Sr-Nd isotope data are reported for intrusive rocks and crystal tuff of the Elashan Formation in the Hutouya area. Moreover, Re-Os ages and S-Pb isotopes are also reported for the ore minerals in the Hutouya deposit. The Zircon laser ablation–inductively coupled plasma–mass spectrometry (LA–ICP–MS) U-Pb age of granodiorite and Re-Os isochron age of molybdenite suggest that mineralizations occurred at ca. 227 Ma and that the granodiorite and molybdenite are closely related petrogenetically. All the granitoids in the Hutouya deposit are high-K calc-alkaline and metaluminous to weakly peraluminous I-type granitoids. Among them, the ore-forming granitoids were derived by the mixing of crust-derived (either juvenile or ancient mature lower crust) and mantle-derived magmas, whereas the non-ore-related granite porphyry was generated by the partial melting of a single ancient mature lower crust. The magmas of all the granitoids underwent extensive fractionation–crystallization during the process of rising and emplacement. The sulfur of the analyzed samples from the northern and middle zone of Hutouya deposit (including No. II, III, IV, and VI ore belts) belongs to deep magmatic sulfur, while the sulfur of samples from the southern zone of Hutouya deposit (No. VII ore belt) includes not only deep magmatic sulfur but also a contribution of strata sulfur. All the ore mineral samples in the Hutouya deposit have similar Pb compositions that are consistently derived from a mixed source of upper crust and mantle. Tectonic discrimination diagrams indicate a post-collisional setting for all granitic rocks of the Hutouya skarn deposit, which is therefore considered a product of a the post-collision extensional system and is consistent with other porphyry-skarn deposits within the East Kunlun Orogenic Belt.
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Li, Haoran, Ye Qian, Fengyue Sun, Jinlei Sun, and Guan Wang. "Zircon U–Pb dating and sulfide Re–Os isotopes of the Xiarihamu Cu–Ni sulfide deposit in Qinghai Province, Northwestern China." Canadian Journal of Earth Sciences 57, no. 8 (August 2020): 885–902. http://dx.doi.org/10.1139/cjes-2019-0107.
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The Xiarihamu Cu–Ni sulfide deposit is the second-largest Cu–Ni deposit in China, located in the Eastern Kunlun orogenic belt. However, despite previous study, the formation and evolution of this deposit remains a key unknown in the tectonic evolution of the Eastern Kunlun Orogenic Belt. Moreover, the petrogenesis of the ore-bearing rocks and the nature of ore genesis are the subjects of ongoing debate. Here, we present detailed field observations, petrology, zircon U–Pb geochronology, and Re–Os isotopic analyses to constrain the timing and genesis of the Xiarihamu Cu–Ni sulfide deposit. Sulfides from the massive ores yielded a Re–Os isotopic isochron age of 408 ± 11 Ma. Four samples from the ore-bearing Xiarihamu mafic–ultramafic intrusions yielded zircon U–Pb ages of 423.1 ± 2 Ma, 422.9 ± 3.1 Ma, 422.7 ± 2.3 Ma, and 422.6 ± 2.7 Ma, respectively, indicating that the ore formed during the Silurian. The calculated initial 187Os/188Os ratio and γOs values ranged from 0.5109 to 0.8499 and from 311 to 584, respectively, indicating that crustal contamination played an extremely important role in triggering sulfide saturation. In combination with previous research, drill core observations and Re–Os data provide robust evidence for multiple pulses of magma replenishment throughout the process of ore genesis. Based on this evidence, the large-scale magmatic Cu–Ni mineralization in Xiarihamu likely occurred in a post-collisional setting related to tectonic slab breakoff.
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Carl, C., E. von Pechmann, A. Höhndorf, and G. Ruhrmann. "Mineralogy and U/Pb, Pb/Pb, and Sm/Nd geochronology of the Key Lake uranium deposit, Athabasca Basin, Saskatchewan, Canada." Canadian Journal of Earth Sciences 29, no. 5 (May 1, 1992): 879–95. http://dx.doi.org/10.1139/e92-075.
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The Key Lake deposit is one of several large, high-grade, unconformity-related uranium deposits located at the eastern margin of the Athabasca Basin in northern Saskatchewan, Canada. The deposit consists of the Gaertner orebody, now mined out, and the Deilmann orebody, which is presently being mined. In the past, radiometric dating efforts yielded an age of oldest ore-forming event of 1250 ± 34 Ma at the Gaertner orebody and 1350 ± 4 Ma at the Deilmann orebody. This unlikely age difference called for further investigation. Innovative preparation techniques were used to separate the paragenetically oldest U mineral, an anisotropic uraninite. Ore microscopy and U/Pb isotopic data show that the oldest event of uranium emplacement occurred simultaneously at the two orebodies, at 1421 ± 49 Ma. The primary ore-forming phase was followed by younger generations of U mineralization and periods of remobilization. Sm/Nd data of Key Lake uraninite form an isochron corresponding to an age of 1215 Ma. This is interpreted as the age of a uranium remobilization or a new mineralizing event. The lead found in the Athabasca Group above the Deilmann deposit and in galena appears to be a mixture of a common lead and radiogenic lead mobilized from the orebody over a time span of at least 1000 Ma.
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Liang, Enyun, Dezhi Huang, Guangqian Zeng, Gengyin Liu, Guangjun Zou, Peng Luo, and Di Chen. "Metallogenesis of the Bawang Sn-Zn Polymetallic Deposit, Wuxu Ore Field, Guangxi, South China: U-Pb Dating and C-O-S-Pb Isotopic Constraints." Minerals 12, no. 2 (January 25, 2022): 137. http://dx.doi.org/10.3390/min12020137.
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The Bawang deposit, located in the west of Wuxu ore field, southern section of the Nandan-Hechi metallogenic belt, is a medium-sized tin–zinc polymetallic deposit. Its genesis has been a matter of debate because of lacking constraints from isotope geology. In this study, LA-MC-ICP-MS U-Pb dating of cassiterite and C-O-S-Pb isotope analyses of monominerals were used to investigate the mineralization age and source of the ore-forming minerals in the Bawang deposit. LA-ICP-MS U–Pb dating of cassiterite yielded ages of 93.1 ± 4.8 Ma and 85.3 ± 6.3 Ma, indicating that the mineralization occurred in the early Late Cretaceous. The δ13CPDB and δ18OSMOW values of calcites at the ore stage range between −0.41‰ and 0.44‰ (average = −11‰) and between 13.8‰ and 15.40‰ (average = 14.59‰), respectively. This shows that ore fluid sources were a mixture of those derived from magma and stratum. Pyrite and sphalerite have uniform δ34S values (−4.45‰~−2.20‰), indicating that sulfur is also derived from the mixing of magmatic hydrothermal and stratum fluids. The Pb isotopic composition of sulfide (206Pb/204Pb = 18.4055~18.7625, 207Pb/204Pb = 15.6745~15.7209, 208Pb/204Pb = 38.6232~39.0370) is consistent with the granite of the same age, indicating that ore-forming metals are mainly derived from magmatic hydrothermal solution. The Bawang deposit is a hydrothermal vein-type deposit in the external contact zone of Late Cretaceous granite, controlled by tectonic fractures, and formed by the interaction of magmatic hydrothermal fluid and carbonate rock. There may be large skarn-type ore bodies in the deep part. The results of this study provide insights into the research and exploration of similar deposits in Nandan-Hechi metallogenic belt and in the Youjiang Basin.
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Beyer, Steve R., Kurt Kyser, Tom G. Kotzer, Kevin Ansdell, and David Quirt. "Exploration geochemistry of surficial media over the high-grade McArthur River uranium deposit, Saskatchewan, Canada." Canadian Mineralogist 59, no. 5 (September 1, 2021): 913–45. http://dx.doi.org/10.3749/canmin.2000081.
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ABSTRACT An orientation survey using surficial media was performed over the high-grade McArthur River unconformity-related U deposit (Saskatchewan, Canada) to test whether or not secondary dispersion of elements related to the ore body or alteration zone can be detected at the surface more than 500 m above the deposit. Organic-rich Ah-horizon soils, Fe-rich B-horizon soils, C-horizon soils, tree cores of Jack pine (Pinus banksiana), and glacially dispersed boulders of Manitou Falls Formation sandstone that host the U deposit were collected in four sampling grids near the mine site. Two of the grids overlaid the trace of the P2 fault that hosts the deposit and extends nearly to the surface, one grid overlaid both the P2 fault and one of the high-grade ore bodies (Zone 4), and one grid was located 2.5 km away from the ore body surface trace in the barren hanging wall of the P2 fault. The grid overlying the Zone 4 ore body had the highest proportion of samples with elevated U and low 207Pb/206Pb ratios, the latter indicative of radiogenic Pb from a high-U source, measured in two size fractions of Ah-horizon soils using Na pyrophosphate leach, pine tree cores using total digestion, and sandstone boulders using 2% HNO3 leach. A handful of pathfinder elements, such as As, Co, Ni, and Pb, are variably associated with the U and radiogenic Pb. Sandstone boulders with an assemblage of dravite + kaolinite ± illite, determined using shortwave infrared (SWIR) spectroscopy and matching the alteration mineralogy in the Manitou Falls Formation above the U deposit, were prevalent in the grid above the Zone 4 ore body and in the adjacent grid in the direction of glacial dispersion. A coarse fraction of the B-horizon soils, leached with 5% HNO3, highlighted the grid above the Zone 4 ore body to a lesser extent, whereas HNO3 leaches and aqua regia digests of C-horizon soil separates did not highlight the P2 fault or ore body trace due to influence by parent till mineralogy. Results of environmental monitoring at the mine site, which was active at the time of sampling, suggest that dust containing U, Pb, and radionuclides from waste rock piles and a ventilation shaft could influence A-horizon soil geochemistry near the mine site, and that U and radiogenic Pb anomalies in B- and C-horizon soils near the water table are close to a treated mine effluent discharge point. However, older trees that record elevated U and radiogenic Pb in annual rings that pre-date mining activity, and alteration mineralogy and geochemistry of boulders that are less susceptible to the influences of mining activity, add confidence that the geochemical anomaly in diverse surficial media above the Zone 4 ore body represents secondary dispersion from the underlying U deposit.
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Ivanov, B. N., N. A. Donskoy, V. O. Syomka, S. M. Bondarenko, and O. B. Bondarenko. "GEOCHEMICAL CHARACTERISTICS OF NOVOKOSTIANTYNIVKA URANIUM DEPOSIT." Geochemistry and ore formation, no. 42 (2021): 3–11. http://dx.doi.org/10.15407/gof.2021.42.003.
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Paper research aim is to identify characteristics of spacious distribution of radioactive- and associated elements in albitites according to depth and ore-level attribution: case study of 35th survey line of Novokostiantynivka deposit. Geochemical characteristics of Novokostiantynivka deposit are defined by presence of upper and lower ore-bearing levels. Geochemical anomalies related to upper ore-bearing level have complex character (uranium, thorium, lanthanum, yttrium, ytterbium, vanadium, and zirconium). At apical part of the deposit (Eastern fault) the albitites of blended type (chlorite, rybekite, aegerine) are dominant. La, Th, Y, and U define geochemical trend. These elements are likely to be related to rare-earth mineralization (monazite, apatite, xenotime), to a lesser extent to thorium and uranium mineralization with subordinate zircon. At deeper levels (Western fault) albitites’ mineral composition becomes more monotonous of rybekite-aegerine, and aegerine. The lead elements are Zr, Y, V, U, Th; Zr and Y noticeably dominate over other elements. Both elements and, maybe, part of U are related to zircon (malacon) which is predominant over rare-earth and thorium mineralization. Geochemical anomalies related to lower ore-bearing level are distinctive with monometallic (uranium) trend. The albitites of large column-like body have rybekite-aegerine, or aegerine mineral composition; phlogopite occurs often. Associated elements like Th, La, Y, Yb, V, Zr specific to albitites of upper ore level are not characteristic to deeper one. Based on seldom minor Th, La, and Y content spikes, rare-earth and thorium mineralization is immaterial. Regarding Zr and V, their contents are not over but most of the time less than background values. Apparently, zircon is not formed in albitites of lower ore-level; vanadium content in darkcolored minerals becomes insignificant, and single lead element is uranium. The most essential feature of Novokostiantynivka deposit is a succession of complex mineralization with monometallic one with depth.
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Rizvanova, Nailya G., Antonina A. Alenicheva, Sergey G. Skublov, Sergey A. Sergeev, and Dmitriy A. Lykhin. "Early Ordovician Age of Fluorite-Rare-Metal Deposits at the Voznesensky Ore District (Far East, Russia): Evidence from Zircon and Cassiterite U–Pb and Fluorite Sm–Nd Dating Results." Minerals 11, no. 11 (October 20, 2021): 1154. http://dx.doi.org/10.3390/min11111154.
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This article presents new isotope-geochronological results for the granites of the Voznesensky ore district (southeastern part of the Khanka massif). The granites are associated with extensive rare-metal–fluorite, tin and tantalum mineralization. Despite the numerous published results of Rb–Sr, Sm–Nd and U–Pb dating of ore-bearing granites and associated ores, the issues of age correlation and the genetic relationship of igneous rocks and mineralization remain unclear. U–Pb zircon SHRIMP dating reveals synchronous ages of 478 ± 4 Ma and 481 ± 7 Ma for two samples of biotite leucogranites as the age of magmatic crystallization of the Voznesensky granites. The composition of the studied zircon demonstrates the typical features of magmatic zircon and has the typical features of zircon exposed to fluids at the late/post-magmatic stage. Sm–Nd ID-TIMS dating of the fluorite of the Voznesenskoe deposit yields an age of 477 ± 9 Ma, and U–Pb ID-TIMS dating of cassiterite from the Yaroslavskoe and Chapaevskoe tin deposits yields an age of 480 ± 4 Ma, which confirms the direct genetic and age relationship of ore formation with granite magmatism.
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Yang, Tianjian, Xiaoming Sun, Guiyong Shi, and Ying Liu. "LA-ICP-MS U–Pb Dating of Cenozoic Rutile Inclusions in the Yuanjiang Marble-Hosted Ruby Deposit, Ailao Shan Complex, Southwest China." Minerals 11, no. 4 (April 19, 2021): 433. http://dx.doi.org/10.3390/min11040433.
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Among the marble-hosted ruby deposits in the Himalayan tectonic belt, which yields the highest-quality rubies in the world, the Yuanjiang deposit is the only economically viable one located in China. More attempts are necessary to put constraints on the ore-forming age of these marble-hosted ruby deposits. Here, we dated rutile inclusions in the Yuanjiang rubies using the LA-ICP-MS U–Pb method, which yielded a lower intercept 206Pb/238U age of 20.2 ± 1.2 Ma on the Tera-Wasserburg plot, close to the 22.5–22.2 Ma 40Ar/39Ar ages of phlogopite from the ruby host matrix assemblage. Our U–Pb rutile age put a constraint on the cooling history of the Yuanjiang rubies deposit. The new rutile age is consistent with our previous model that shows the ca. 28–22 Ma left lateral shearing plays an important role in transporting the ruby deposit toward the surface. This study provides the first example of in-situ U–Pb dating of rutile in the Himalayan tectonic belt, demonstrating the great potential of U–Pb rutile geochronology for Cenozoic mineral deposits.
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Wu, Tong, Ruidong Yang, Junbo Gao, and Jun Li. "Age of the lower Cambrian Vanadium deposit, East Guizhou, South China: Evidences from age of tuff and carbon isotope analysis along the Bagong section." Open Geosciences 13, no. 1 (January 1, 2021): 999–1012. http://dx.doi.org/10.1515/geo-2020-0287.
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Abstract The early Cambrian is a critical interval of dramatic oceanic and biochemical changes in geological history. The black shale deposits, which are rich in Mo, Ni, V, and platinum group elements (PGE), are a reflection of that interval. Among all known Cambrian black shale deposits in South China, the vanadium deposits are poorly constrained by geochronology. The newly discovered tuff layer in the Sansui Bagong vanadium deposit in Guizhou Province can provide excellent constraints on the age of vanadium deposits. In this study, we obtain a new zircon U–Pb isotopic age, which can constrain the age of the vanadium deposit. This tuff occurs in the middle part of the ore bed, and the age of the tuff layer can reflect the mineralization age of the V deposit. Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) is used in this study to obtain the zircon U–Pb age of the tuff and indicates that the event of volcanic activity took place at 520.9 ± 1 Ma. This age is close to the boundary between the Cambrian Terreneuvian and Series 2. This result provides a good constraint on the age of the vanadium deposits in South China and makes the vanadium deposits to be comparable with other Mo–Ni–PGE deposits. The alteration of organic carbon isotope (δ 13Corg) values can reflect changes in the marine environment and is widely used in stratigraphic correlation. The analysis of the δ 13Corg values of the ore bed in the present study reveals a positive excursion at the bottom of the deposit and a negative excursion in the V-enriched layer. The δ 13Corg values in the Bagong section are comparable to those in the Xiaotan and Longbizui sections. The ages of the Sansui vanadium deposit constrained by the U–Pb isotopic age of the tuff and the δ 13Corg values are consistent. All of the data lead us to infer that the vanadium deposit formed at approximately 521 Ma.
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Lukáč, Stanislav, and Beata Zatwarnicka-Madura. "The Logistic Model of the U-Mo Ore Deposit Opening." Applied Mechanics and Materials 708 (December 2014): 196–201. http://dx.doi.org/10.4028/www.scientific.net/amm.708.196.
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The article deals with the creation of a logistic model of the deposit opening and preparation, applied to the U-Mo ore deposit in Kurišková. The logistics system consisting of the deposit layout, transportation system, exploitation system, processing, proposed bunkers, production capacities calculation, and the planning and management system has a decisive impact on the economic efficiency of a mining company. With regard to the article extent, only selected elements of the logistics system are described herein.
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Bushuev, Yackov Yur’evich, Vasilii Ivanovich Leontev, and Maria M. Machevariani. "Geochemical Features of Au-Te Epithermal Ores of the Samolazovskoye Deposit (Central Aldan Ore District, Yakutia)." Key Engineering Materials 769 (April 2018): 207–12. http://dx.doi.org/10.4028/www.scientific.net/kem.769.207.
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The Samolazovskoye deposit (Central Aldan ore region, Russia) is confined to the porphyry syenite lopolith (J3-K1), localized between the granitic gneiss Archean basement and the series of the Vendian-Lower Cambrian carbonate cover rocks. Four hydrothermal-metasomatic parageneses have been identified within the deposit: skarn paragenesis, developed on the syenites and carbonate cover rocks contact; so called «gumbaite» paragenesis (kalifeldspar + fluorite + carbonate ± quartz), superimposed on the intrusive massif rocks; feldspatholitic paragenesis (quartz + feldspar), developed in the granitic gneisses of the crystalline basement; ore-bearing fluorite-roscoelite-carbonate-quartz paragenesis, superimposed on all of the above. The article compares ores evolved within gumbaitic syenites, basement feldspatholites and breccias, composed of all the above-mentioned rocks clasts. The geochemical study of given ores, resulted in two identified elements associations: gold-telluride (Au, Sb, As, V, Tl, Te, Hg, W) related to the fluorite-roscoelite-carbonate-quartz hydrothermal-metasomatic paragenesis and (uranium)-polymetallic (Bi, Cu, Pb, Zn, Mo, Se, Li, U), associated with the syenites gumbaitization (?). There is only gold-telluride association within the basement ore bodies, while the ore bodies localized in the syenites intrusion hold both associations, along with the Au and Ag contents being an order of magnitude higher. Breccia ores are characterized by the maximum concentrations of the ore elements. Gold-telluride association of the Samoazovsky deposit ores is specific to epithermal Au-Te mineralization associated with alkaline (A-type) magmatism.
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Chang, Ze-Guang, Guo-Chen Dong, and Alireza K. Somarin. "U–Pb Dating and Trace Element Composition of Zircons from the Gujiao Ore-Bearing Intrusion, Shanxi, China: Implications for Timing and Mineralization of the Guojialiang Iron Skarn Deposit." Minerals 10, no. 4 (March 31, 2020): 316. http://dx.doi.org/10.3390/min10040316.
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The Gujiao ore field, located in the middle segment of the Lüliang Mountain in central North China Craton (NCC), is one of iron skarn deposits of western iron belt in China. The U–Pb dating results of zircon by LA-ICP-MS suggest that the ore-related monzonite from the Guojialiang deposit was formed at 129.7 ± 1.7 Ma, early Cretaceous, which is consistent with the timing of iron skarn deposits in the Handan–Xingtai district of western iron belt. The zircons of monzonite present notable positive Ce anomalies (Ce/Ce* = 23.38–45.85), high Ce4+/Ce3+ values (154–385) and relatively high oxygen fugacity (fO2 = −13.09 to −15.36), and yield relatively low Ti-in-zircon temperatures. The physico-chemical conditions of the Guojialiang deposit were quite similar to these of ore-bearing plutons in the Handan-Xingtai district. The ore-bearing magmas are derived from the enriched lithospheric mantle with crustal material contribution, which played key role in oxidation state of the magma and the iron mineralization in the western iron belt.
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Asghar, Fiaz, Zhanxue Sun, Gongxin Chen, Yipeng Zhou, Guangrong Li, Haiyan Liu, and Kai Zhao. "Geochemical Characteristics and Uranium Neutral Leaching through a CO2 + O2 System—An Example from Uranium Ore of the ELZPA Ore Deposit in Pakistan." Metals 10, no. 12 (December 1, 2020): 1616. http://dx.doi.org/10.3390/met10121616.
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Geochemical characterization studies and batch leaching experiments were conducted to explore the effects of a CO2 + O2 leaching system on uranium (U) recovery from ores obtained from an eastern limb of Zinda Pir Anticline ore deposit in Pakistan. The mineralogy of the ore was identified by Electron Probe Micro-analyzer (EPMA) and Scanning Electron Microscope-Energy Dispersive Spectrometer (SEM-EDS), showing that pitchblende is the main ore mineral. XRD was also used along with EPMA and SEM characterization data. Experimental results indicate that U mobility was readily facilitated in the CO2 + O2 system with Eh 284 mV and pH 6.24, and an 86% recovery rate of U3O8 was obtained. U speciation analysis implied the formation of UO2 (CO3)22− in the pregnant solution. The plausible mechanism may be attributed to the dissolved CO2 gas that forms carbonate/bicarbonate ion releasing oxidized U from the ore mineral. However, U recovery in the liquid phase was shown to decrease by higher U(VI) initial concentration, which may be due to the saturation of Fe adsorption capacity, as suggested by an increase in Fe concentration with increasing initial U(VI) concentration in the solid phase. However, further studies are needed to reveal the influencing mechanism of U(VI) initial concentration on U recovery in the solid phase. This study provides new insights on the feasibility and validity of the site application of U neutral in situ leaching.
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Wu, Jing, Zhi Li, Minjie Zhu, Wenting Huang, Juan Liao, Jian Zhang, and Huaying Liang. "Genesis of the Beixiang Sb-Pb-Zn-Sn Deposit and Polymetallic Enrichment of the Danchi Sn-Polymetallic Ore Belt in Guangxi, SW China." Minerals 12, no. 11 (October 25, 2022): 1349. http://dx.doi.org/10.3390/min12111349.
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Antimony deposits contain little Sn, whereas Sb and Pb are not the principally contained metal of granite-related Sn deposits. The Danchi Sn-metallogenic ore belt (DSOB) in southwestern China is characterized by Sn-Sb-Zn-Pb co-enrichment, yet the triggers are poorly constrained. The Beixiang deposit in the southern DSOB consists of stage I Sn-Zn and stage II Sb-Pb-Zn mineralization. Here, we analyzed the cassiterite U-Pb age, fluid inclusion H-O and sulfide Pb-S isotopes, and calcite trace elements of the Beixiang ores. By comparing with the Dachang and Mangchang Sn-polymetallic ore-fields within the DSOB, we constrained the timing of regional mineralization and revealed the processes causing the Sb-Pb co-enrichment. The cassiterite U-Pb dating yielded 90.6±4.5 Ma (MSWD = 2.6), similar to the ages of the Dachang and Mangchang ore fields, indicating the Late Cretaceous mineralization event throughout the DSOB. The fluid inclusions from stage II ore have δ18OH2O (−2.8 to −7.8‰) and δDV-SMOW (−90.5 to −59.3‰), and the synchronous calcite features have low REE contents, upward-convex REE patterns, and weak Eu anomalies. These suggest that the ore fluids were derived from meteoric water and oil field brine, which dissolved S and Pb from local strata as recorded by sulfide sulfur (δ34SV-CDT = −6.2 to −4.0‰) and Pb isotopes. However, calcite from the stage I ore have higher REE contents and (La/Yb)N, with strong positive Eu anomalies, indicating that the Sn-rich ore fluids were released by greisenization of granite. Overall, we suggest that the combination of granitic magma- and oil field brine-derived fluids, rich in Sn-Zn and Sb-Pb-Zn, respectively, caused the co-enrichment of Sn-Sb-Pb-Zn in Beixiang and throughout the DSOB.
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Yakubovich, Olga, Ilya Vikentyev, Ekaterina Ivanova, Mary Podolskaya, Ivan Sobolev, Eugenia Tyukova, and Alexander Kotov. "U-Th-He Geochronology of Pyrite from Alteration of the Au-Fe-Skarn Novogodnee-Monto Deposit (Polar Urals, Russia)—The Next Step in the Development of a New Approach for Direct Dating of Ore-Forming Processes." Geosciences 11, no. 10 (September 27, 2021): 408. http://dx.doi.org/10.3390/geosciences11100408.
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We report on the application of the U-Th-He method for the direct dating of pyrite from the alteration halo of the Novogodnee-Monto Au-Fe-skarn deposit, Polar Urals. The deposit is genetically related to the formation of volcanogenic complexes of the Ural Paleozoic belt. A modification of the original methodology for measuring U, Th and He isotopes in a single grain allowed us to determine a U-Th-He age of 382 ± 8 Ma (2σ) based on six pyrite samples from the altered rocks of the deposit (U mass fraction ~0.2 mg/kg; Th/U ~ 3.5; 4He specific volume ~ 10−5 cm3·STP·g−1). This age is consistent with estimates of the age of ore formation and coeval with the end of the period of island arc magmatic activity. Our results indicate that U-Th-He dating for pyrite samples of ~1 mg in weight from the hydrothermal-metasomatic halo of ore bodies is possible, providing a crucial next step in the development of U-Th-He pyrite geochronology.
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Wei, Chen, Lin Ye, Zhilong Huang, Wei Gao, Yusi Hu, Zhenli Li, and Jiawei Zhang. "Ore Genesis and Geodynamic Setting of Laochang Ag-Pb-Zn-Cu Deposit, Southern Sanjiang Tethys Metallogenic Belt, China: Constraints from Whole Rock Geochemistry, Trace Elements in Sphalerite, Zircon U-Pb Dating and Pb Isotopes." Minerals 8, no. 11 (November 8, 2018): 516. http://dx.doi.org/10.3390/min8110516.
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The Laochang Ag-Pb-Zn-Cu deposit, located in the southern margin of the Sanjiang Tethys Metallogenic Belt (STMB), is the typical Ag-Pb-Zn-Cu deposit in this region. Its orebodies are hosted in the Carboniferous Yiliu Formation volcanic-sedimentary cycle and occur as stratiform, stratoid and lenticular. Whether or not the stratabound ore belong to the volcanogenic massive sulfide (VMS) deposit remains unclear and controversial. In this paper, the whole rock geochemistry, trace elements in sphalerite, U-Pb zircon chronology and Pb isotopes were investigated, aiming to provide significant insights into the genesis and geodynamic setting of the Laochang deposit. Lead isotope ratios of pyrite and sphalerite from the stratabound ore are 18.341 to 18.915 for 206Pb/204Pb; 15.376 to 15.770 for 207Pb/204Pb; and 38.159 to 39.200 for 208Pb/204Pb—which display a steep linear trend on Pb-Pb diagrams. This indicates a binary mixing of lead components derived from leaching between the host volcanic rock and mantle reservoir. Sphalerite from stratabound ores is relatively enriched in Fe, Mn, In, Sn, and Ga—similar to typical VMS deposits. Moreover, the Carboniferous volcanic rock hosting the stratabound Ag-Pb-Zn-Cu ores has a zircon U-Pb age of 312 ± 4 Ma; together with previous geochronological and geological evidences, thus, we consider that the stratabound mineralization occur in the Late Paleozoic (~323–308 Ma). Collectively, these geologic, geochemical, and isotopic data confirm that the stratabound ores should be assigned to Carboniferous VMS mineralization. In addition, volcanic rocks hosting the stratabound ore exhibit elevated high field strength elements (HFSEs, Nb, Ta, Zr and Hf) abundance, slight enrichment of light rare earth element (LREE), and depletion of Ba and Sr with obvious Nb-Ta anomalies. Such characteristics suggest that their magma is similar to typical oceanic island basalt. In addition, the oceanic island basalt (OIB)-like volcanic rocks were formed at Late Paleozoic, which could be approximately synchronous with the VMS mineralization at Laochang. Thus, it is suggested that the Laochang VMS mineralization was generated in the oceanic island setting prior to the initial subduction of the Changning-Menglian Paleo-Tethys Ocean.
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Du, Shengjiang, Hanjie Wen, Shirong Liu, Chaojian Qin, Yongfeng Yan, Guangshu Yang, and Pengyu Feng. "Mineralogy and Metallogenesis of the Sanbao Mn–Ag (Zn-Pb) Deposit in the Laojunshan Ore District, SE Yunnan Province, China." Minerals 10, no. 8 (July 23, 2020): 650. http://dx.doi.org/10.3390/min10080650.
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The Sanbao Mn–Ag (Zn-Pb) deposit located in the Laojunshan ore district is one of the most important deposits that has produced most Ag and Mn metals in southeastern Yunnan Province, China. Few studies are available concerning the distribution and mineralization of Ag, restricting further resource exploration. In this study, detailed mineralogy, chronology, and geochemistry are examined with the aim of revealing Ag occurrence and its associated primary base-metal and supergene mineralization. Results show that manganite and romanèchite are the major Ag-bearing minerals. Cassiterite from the Mn–Ag ores yielded a U–Pb age of 436 ± 17 Ma, consistent with the Caledonian age of the Nanwenhe granitic pluton. Combined with other geochemical proxies (Zn-Pb-Cu-Sn), the Sanbao Mn–Ag deposit may originally be of magmatic hydrothermal origin, rather than sedimentary. The Ag-rich (Zn-Pb (Sn)-bearing) ore-forming fluids generated during the intrusion of the granite flowed through fractures and overprinted the earlier Mn mineralization. Secondary Ag (and possibly other base-metals) enrichment occurred through later supergene weathering and oxidation.
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Philippe, S., and J. Lancelot. "U-Pb geochronological investigation of the cigar lake U ore deposit, Saskatchewan." Chemical Geology 70, no. 1-2 (August 1988): 135. http://dx.doi.org/10.1016/0009-2541(88)90587-6.
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Ding, Bo, Hongxu Liu, Deru Xu, Linfei Qiu, and Weihong Liu. "Mineralogical Evidence for Hydrothermal Uranium Mineralization: Discovery and Genesis of the Uranyl Carbonate Minerals in the BLS U Deposit, SW Songliao Basin, Northeast China." Minerals 13, no. 3 (February 28, 2023): 339. http://dx.doi.org/10.3390/min13030339.
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Diabase intrusions have been widely found in sandstone-type U deposits of the southwestern Songliao Basin, indicating diabase-related hydrothermal fluids might play an important role in this type of U mineralization. The first discovery of U-bearing carbonate minerals in the BLS U deposit provides an opportunity for understanding hydrothermal U mineralization and its relationship to diabase intrusions. U-bearing carbonate minerals occurred as thin shells generally ringing ankerite and then surrounded by colloidal pyrite through examination of scanning electron microscopy and energy dispersive spectroscopy. They can be interpreted as uranyl carbonate minerals, with the empirical formula of Ca2.7Fe0.9Mg0.4 (UO2) (CO3)5•9.6H2O, based on infrared absorption spectroscopy and electron microprobe. The formation of uranyl carbonate minerals is most likely related to the CO2-rich hydrothermal fluids from diabase intrusions according to its occurrence state, but the key factors are that the Ca-UO2-CO3 ternary complexes should have been produced in ore-forming hydrothermal fluids and adsorption of ankerite on ternary complexes. Thereby, a potential diabase-related hydrothermal U mineralization model for sandstone-type U deposits can be proposed. The ore-forming fluids that originated from diabase-related hydrothermal are formed through continuously extracting the adsorbed U6+ and dissolving the early U minerals. Then, U in the ore-forming hydrothermal fluids was migrated and transported probably either as uranyl carbonate ions or as Ca-UO2-CO3 ternary complexes. The former is easy to precipitate in the form of pitchblende dispersed in the fossil wood cells, ringing pyrite, and occurring along the edge of adsorbents at the site of reducing capacity change, while the latter will extremely inhibit the reduction of U6+, eventually leading to the precipitation of uranyl carbonate minerals ringing ankerite by adsorption. The above research results can provide mineralogical evidence for hydrothermal U mineralization in sandstone-type U deposits of the Songliao Basin.
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Wang, Xinyu, Shulai Wang, Huiqiong Zhang, Yuwang Wang, Xinyou Zhu, and Xing Yang. "Geochemical Characteristics of the Mineral Assemblages from the Niukutou Pb-Zn Skarn Deposit, East Kunlun Mountains, and Their Metallogenic Implications." Minerals 13, no. 1 (December 23, 2022): 18. http://dx.doi.org/10.3390/min13010018.
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The Niukutou Pb-Zn deposit is typical of skarn deposits in the Qimantagh metallogenic belt (QMB) in the East Kunlun Mountains. In this study, based on detailed petrographical observations, electron microprobe analyses (EMPAs), and laser-ablation–inductively coupled plasma–mass spectrometry (LA-ICP-MS) analyses, we report the major and trace element compositions of the typical skarn mineral assemblages (garnet, pyroxene, ilvaite, epidote, and chlorite) in this deposit. Three hydrothermal mineralization stages with different mineral assemblages of the prograde metamorphic phase were determined, which were distributed from the inside to the outside of the ore-forming rock mass. Grt1+Px1 (Stage 1), Grt2+Px2 (Stage 2), and Px3 (Stage 3) were distinguished in the Niukutou deposit. Furthermore, the ilvaites in the retrograde metamorphic phase can be divided into three stages, namely Ilv1, Ilv2, and Ilv3. The ore-forming fluid in Stage 1 exhibited high ∑REE, U, and Nd concentrations and δEu, δCe, and LREE/HREE values, which were likely derived from a magmatic–hydrothermal source and formed at high temperatures, high fO2 values, and mildly acidic pH conditions, and probably experienced diffusive metasomatism in a closed system with low water/rock ratios. In Stages 2 and 3, the ore-forming exhibited lower ∑REE, U, and Nd concentrations and δEu, δCe, and LREE/HREE values, with high Mn content that had likely experienced infiltrative metasomatism in an open system with high water/rock ratios. From Ilv1 to Ilv3, the δEu and U contents decreased, whereas the Mn content increased, indicating that the oxygen fugacity of mineralization was in decline. The ore-forming fluid evolution of the Niukutou deposit can be characterized as follows: from Stage 1 to Stage 3, the hydrothermal fluid migrated from the deep plutons to the shallow skarn and marble; the environment altered from the high fO2 and temperature conditions to low fO2 and temperature values, and the pH and Mn contents increased. The fluids contained considerable metal ore-forming materials that were favorable for the enrichment and precipitation of the Fe content. In the retrograde metamorphic phase, with the decrease in oxygen fugacity (from Ilv1 to Ilv3), the temperature and oxygen fugacity of the theore-forming fluid environment decreased, ultimately becoming conducive to the dissolution and precipitation of Pb and Zn elements.
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Philippe, S., J. R. Lancelot, N. Clauer, and A. Pacquet. "Formation and evolution of the Cigar Lake uranium deposit based on U–Pb and K–Ar isotope systematics." Canadian Journal of Earth Sciences 30, no. 4 (April 1, 1993): 720–30. http://dx.doi.org/10.1139/e93-058.
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A systematic geochronological study was conducted on the Cigar Lake uranium deposit. U–Pb and Pb–Pb systematics were applied to different types of uranium ore, and various associated sheet silicates were dated by the K–Ar method. These two approaches define a widespread retrograde metamorphic event in the basement, which occurred at about 1780 Ma during the Hudsonian orogeny, and a four-stage evolutionary model for the ore deposit. This model is compatible with the history of other unconformity-type, uranium deposits in the Athabasca Basin.The first stage in the evolution of the Cigar Lake uranium deposit is marked by uraninite crystallization at 1341 ± 17 Ma, which, in association with arsenides and sulpharsenides, constitutes the mineralization of economic interest (main orebody). The second stage, characterized by a Fe-kaolinite and Fe-illite paragenesis, occurred locally at about 900 Ma. The third stage involved uranium mobilization at about 325 Ma and is characterized by (i) preferential loss of radiogenic lead from primary uraninite and crystallization of pitchblende at the rims of uraninite grains and (ii) formation of pitchblende associated with Fe-sulphides or hematite in the main and perched orebodies. The last stage is characterized by recent alteration and coffinitization which have affected all ore types.
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Pan, Jun-Yi, Pei Ni, Zhei Chi, Wen-Bin Wang, Wen-Can Zeng, and Kai Xue. "Alunite 40Ar/39Ar and Zircon U-Pb Constraints on the Magmatic-Hydrothermal History of the Zijinshan High-Sulfidation Epithermal Cu-Au Deposit and the Adjacent Luoboling Porphyry Cu-Mo Deposit, South China: Implications for Their Genetic Association." Economic Geology 114, no. 4 (June 1, 2019): 667–95. http://dx.doi.org/10.5382/econgeo.4658.
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AbstractThe large Zijinshan high-sulfidation epithermal Cu-Au deposit, together with the adjacent Luoboling porphyry Cu-Mo deposit, constitutes a major porphyry-epithermal ore district in South China. Current debate centers on whether the Zijinshan and the adjacent Luoboling deposits are cogenetic or represent separate ore-forming events, which is a question of importance for exploration in the district. In this contribution, the magmatichydrothermal history of the relationship between Zijinshan and Luoboling is reconstructed based on new alunite 40Ar/39Ar ages from Zijinshan and zircon U-Pb ages of ore-related intrusions from both deposits. This study has been complemented by S isotope analysis on the dated alunite to assess their origin.Three types of coexisting alunite and sulfide assemblages exist at Zijinshan, namely, (1) alunite-quartz-covellite cemented breccias; (2) alunite-digenite veins and (3) banded alunite-pyrite veins. Their field occurrences and S isotope features suggest a magmatic-hydrothermal origin for alunite-quartz-covellite cemented breccias and alunite-digenite veins, whereas the origin of alunite-pyrite veins is likely to be related to magmatic steam. Given the intimate textural coexistence between sulfides and alunite, four undisturbed 40Ar/39Ar plateau ages obtained from alunite-quartz-covellite cemented breccia and alunite-digenite vein-type alunite define the timing of Zijinshan high-sulfidation mineralization from 102.86 ± 0.61 to 101.19 ± 0.60 Ma. These agree with bracketing zircon U-Pb ages of pre-ore dacite porphyry at 104.8 ± 0.9 Ma and 104.7 ± 0.5 Ma and a zircon U-Pb age of a post-ore granite porphyry dike at 99.5 ± 0.7 Ma. Combined with their field occurrences, the four alunite ages may imply episodic hydrothermal pulses and a possible time span of over 500 k.y. for the overall high-sulfidation mineralization. Two alunite samples from alunite-pyrite veins yield a slightly disturbed 40Ar/39Ar plateau age at 101.67 ± 0.61 Ma and an apparently undisturbed age at 99.91 ± 0.59 Ma, probably reflecting partial or complete thermal resetting related to the coeval granite porphyry dikes. At Luoboling, zircon U-Pb analysis yields an age of 133.6 ± 1.1 Ma for a dark, ore vein-bearing quartz-diorite porphyry sample and confirms the petrographic observation that they are xenoliths of early wall rocks for the porphyry mineralization. A granodiorite porphyry sample with abundant A-veins is interpreted as an intermineral porphyry phase, dated at 106.5 ± 1.4 Ma. This age is interpreted as the upper limit for porphyry Cu-Mo mineralization and agrees well with previously reported molybdenite Re-Os and biotite 40Ar/39Ar ages, which collectively suggest porphyry Cu-Mo mineralization and potassic alteration at Luoboling were formed within the interval between ca. 106 and 104 Ma.Taken together, the age of the Zijinshan high-sulfidation mineralization is substantially younger than the porphyry mineralization at Luoboling, and we conclude that there is no direct genetic link between the two deposits. However, the Zijinshan Cu-Au deposit is temporally associated with the deep porphyritic granodiorite, which gives zircon U-Pb ages from 102.1 ± 0.8 to 101.8 ± 0.5 Ma, overlapping with the alunite 40Ar/39Ar ages for the high-sulfidation mineralization. This finding has important implications for the ongoing exploration for the two mineralization types in the ore district and elsewhere.
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Neymark, Leonid A., Anatoly M. Larin, and Richard J. Moscati. "Pb-Pb and U-Pb Dating of Cassiterite by In Situ LA-ICPMS: Examples Spanning ~1.85 Ga to ~100 Ma in Russia and Implications for Dating Proterozoic to Phanerozoic Tin Deposits." Minerals 11, no. 11 (October 22, 2021): 1166. http://dx.doi.org/10.3390/min11111166.
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This paper investigates applicability of cassiterite to dating ore deposits in a wide age range. We report in situ LA-ICPMS U-Pb and Pb-Pb dating results (n = 15) of cassiterite from six ore deposits in Russia ranging in age from ~1.85 Ga to 93 Ma. The two oldest deposits dated at ~1.83–1.86 Ga are rare metal Vishnyakovskoe located in the East Sayan pegmatite belt and tin deposits within the Tuyukan ore region in the Baikal folded region. Rare metal skarn deposits of Pitkäranta ore field in the Ladoga region, Fennoscandian Shield are dated at ~1.54 Ga. Cassiterite from the Mokhovoe porphyry tin deposit located in western Transbaikalia is 810 ± 20 Ma. The youngest cassiterite was dated from the deposits Valkumei (Russian North East, 108 ± 2 Ma) and Merek (Russian Far East, 93 ± 2 Ma). Three methods of age calculations, including 208Pb/206Pb-207Pb/206Pb inverse isochron age, Tera-Wasserburg Concordia lower intercept age, and 207Pb-corrected 206Pb*/238U age were used and the comparison of the results is discussed. In all cases, the dated cassiterite from the ore deposits agreed, within error, with the established period of magmatism of the associated granitic rock.
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Cong, Pang, Wang, Tian, Ying, and Huang. "Zircon LA-ICP-MS U-Pb Ages and the Hf Isotopic Composition of the Ore-Bearing Porphyry from the Yanghuidongzi Copper Deposit, Heilongjiang, China, and Its Geological Significance." Minerals 9, no. 11 (November 2, 2019): 676. http://dx.doi.org/10.3390/min9110676.
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The Yanghuidongzi copper deposit is a typical porphyry copper deposit located at the eastern margin of the Xing’anling-Mongolian Orogenic Belt (XMOB). While much attention have been paid to the ore-forming age of the deposit and the magma source of the ore-bearing porphyry, this paper approaches this issue with the methods of the LA-ICP-MS zircon U-Pb dating and Lu-Hf isotopic composition of the Yanghuidongzi porphyry copper deposit. The results reveal that the Yanghuidongzi porphyry copper deposit was formed in the Early Jurassic (189.6 ± 1.0 Ma), which corresponds to the time of magmatic activity in this region. The background studies of ore-forming dynamics indicate that the formation of the Yanghuidongzi copper deposit is related to the subduction of the Paleo-Pacific plate. The Yanghuidongzi ore-bearing porphyry zircons have a positive εHf(t) value (4.4–7.0), a high 176Hf/177Hf ratio (0.282786–0.282854), and a two-stage Hf model ages (TDM2) ranging from 783 Ma to 943 Ma, all of which suggest that the Early Jurassic granodiorite porphyry of the Yanghuidongzi deposit was formed by the partial melting of newly grown crustal material from the depleted mantle in the Neoproterozoic.
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Zhao, Yuehua, Shouyu Chen, Yuqiang Huang, Jiangnan Zhao, Xiang Tong, and Xingshou Chen. "U-Pb Ages, O Isotope Compositions, Raman Spectrum, and Geochemistry of Cassiterites from the Xi’ao Copper-Tin Polymetallic Deposit in Gejiu District, Yunnan Province." Minerals 9, no. 4 (March 31, 2019): 212. http://dx.doi.org/10.3390/min9040212.
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: The Xi’ao Cu-Sn polymetallic deposit is located in the inner alteration zone of the Laoka granite. The ore bodies extend to 400 m in the granite rock and primarily occur with fluorite and potassic alterations. Two cassiterite samples of altered rock-type ore and one tourmaline vein-type ore in the Xi’ao Cu-Sn polymetallic deposit yielded U-Pb ages of 83.3 ± 2.1 Ma, 84.9 ± 1.7 Ma, and 84.0 ± 5.6 Ma, respectively. The Raman spectrum peak values of A1g were shifted to a lower frequency, possibly due to the substitution of Sn with Nb, Ta, Fe, and Mn. Measured δ18O values of cassiterite samples and calculated δ18OH2O values for the ore-forming fluid indicate that the latter was mostly derived from magma. The high Fe and Mn abundances for cassiterite are consistent with those of hydrothermal origin. The Nb, Ta, and Ti contents indicate that cassiterites in the Xi’ao deposit likely formed in a metallogenic environment that was largely affected by granitic magmatism. Therefore, we conclude that the Xi’ao deposit is a magmatic hydrothermal deposit.
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Chen, Gongxin, Zhanxue Sun, Yajie Liu, Jinhui Liu, Baoqun Hu, and Hongjun Zhang. "Comparison of different approaches for bioleaching of a granite-type uranium ore." E3S Web of Conferences 98 (2019): 04004. http://dx.doi.org/10.1051/e3sconf/20199804004.
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Uranium bioleaching has been rapidly developed in China during recent years. However, some problems during bioleaching, such as low uranium leaching efficiency for rocks lacking pyrite, remain to be solved. A granite type uranium deposit from southern China was selected for the study of U bioleaching with addition of pyrite. Experiments using four approaches, including (i) pyrite ores mixing with culture, (ii) pyrite tiled on the surface of ores with culture, (iii) no pyrite ores with culture, and (iv) pyrite ores without culture were examined in this study. Results showed that bacteria can improve U leaching efficiency, particularly by adding pyrite into ore. Approach (i) pyrite ores mixing with culture had the highest U concentration and the highest recovery rate of the four approaches. No significant difference was observed between approaches (ii) pyrite tiled on the surface of ores with culture and (iii) no pyrite ores with culture.
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Sheremet, E. М., I. Yu Nikolaev, L. D. Sietaia, and S. М. Strekozov. "Some Aspects of the Geochemistry and Natural Radioactivity of the Azov Deposit Ores." Geochemistry and ore formation, no. 42 (2021): 25–35. http://dx.doi.org/10.15407/gof.2021.42.025.
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The analysis of the Azov deposit of zirconium-rare earth ores as the object capable on qualitative and quantitative parameters to become key for creation and modernization of rare earth subsectors of the industry of Ukraine is carried out. On the basis of the generalized characteristics of zirconium-rare earth mineralization, conclusions were drawn regarding the nature of the increased radioactivity at the Azov deposit, which is mainly due to the presence of certain minerals in the ores. The actual radioactive minerals were found only as inclusions in zircon and do not make a significant contribution to the natural radioactivity of ores. It has been established that the radioactivity is uranium-thorium due to the inclusion of these elements in the composition of the aforementioned minerals. The results of the radiation-hygienic assessment of core samples from the deposit are presented. According to the existing standards, the enclosing rocks of the supra-ore and under-ore strata can be used in all types of construction without restrictions. The ores of the deposit are assigned to the third class in terms of the level of effective specific activity. It was found that there is a significant direct relationship between gamma activity and the total REE content in the field. There is also a correlation between the content of U and Th, the dose rate of γ-radiation and the content of the total REE. It was shown that there is no relationship between these indicators and the ZrO2 content. Analysis of the gamma-ray logs showed the possibility of confidently drawing the boundaries of the ore intervals and fixing the inter-ore intervals. The main stages of the technological process of integrated development, enrichment, processing and storage of enrichment tailings, slags and sludge, which ensure the minimum impact of production on the environment and human health, have been determined.
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McNicoll, Vicki, Gerry Squires, Andrew Kerr, and Paul Moore. "The Duck Pond and Boundary Cu–Zn deposits, Newfoundland: new insights into the ages of host rocks and the timing of VHMS mineralization." Canadian Journal of Earth Sciences 47, no. 12 (December 2010): 1481–506. http://dx.doi.org/10.1139/e10-075.
Full textAbstract:
The Duck Pond Cu–Zn–Pb–Ag–Au deposit in Newfoundland is hosted by volcanic rocks of the Cambrian Tally Pond group in the Victoria Lake supergroup. In conjunction with the nearby Boundary deposit, it contains 4.1 million tonnes of ore at 3.3% Cu, 5.7% Zn, 0.9% Pb, 59 g/t Ag, and 0.9 g/t Au. The deposits are hosted by altered felsic flows, tuffs, and volcaniclastic sedimentary rocks, and the sulphide ores formed in part by pervasive replacement of unconsolidated host rocks. U–Pb geochronological studies confirm a long-suspected correlation between the Duck Pond and Boundary deposits, which appear to be structurally displaced portions of a much larger mineralizing system developed at 509 ± 3 Ma. Altered aphyric flows in the immediate footwall of the Duck Pond deposit contained no zircon for dating, but footwall stringer-style and disseminated mineralization affects rocks as old as 514 ± 3 Ma at greater depths below the ore sequence. Unaltered mafic to felsic volcanic rocks that occur structurally above the orebodies were dated at 514 ± 2 Ma, and hypabyssal intrusive rocks that cut these were dated at 512 ± 2 Ma. Some felsic samples contain inherited (xenocrystic) zircons with ages of ca. 563 Ma. In conjunction with Sm–Nd isotopic data, these results suggest that the Tally Pond group was developed upon older continental or thickened arc crust, rather than in the ensimatic (oceanic) setting suggested by previous studies.
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Savva, N. E., A. V. Volkov, A. A. Sidorov, E. E. Kolova, and K. Yu Murashov. "Primorskoye epithermal Ag-Au deposit (Northeast of Russia): geologic aspects, mineralogic and geochemical features, and ore formation conditions." Геология рудных месторождений 61, no. 1 (January 15, 2019): 52–74. http://dx.doi.org/10.31857/s0016-777061152-74.
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As a potentially large Ag-Au epithermal deposit, Primorskoye comprises the following three areas: Kholodny, Spiridonych, and Teply. This deposit is located in the Omsukchan district of the Magadan Region, where similar deposits, including Dukat, Lunnoye, Goltsovoye, Arylakh, Tidit, and Perevalnoye, have developed. The deposit can be attributed to the Kalalagian volcano-tectonic depression and is localized in a flat-lying rock mass in the Late Cretaceous ignimbrites and rhyolites having thicknesses of greater than 700 m, which is cut through by numerous dykes of medium and major composition. According to the drilling data, the solid mass of leucocratic granites is located in deposits at a depth of 400–500 m with outcrops in the northeastern part of the ore field. The presence of Bi-containing galena and matildite, the availability of mid and high temperature facies of metasomatites (epidote and actinolite), and the specific physical and chemical conditions during the formation of the epithermal Ag-Au ores indicate the intrusive position above and the role of granitoids as generators of high temperature magmatic fluids, which introduced Bi and heated the rocks enclosing the mineralization. The geochemical features of the ores are well correlated with their mineral compositions. The high concentrations of Mn and Ag, elevated concentration of Au, low concentrations of Cu, Pb, Zn, Sb, As, Bi, and Te, low sum of REE, and negative Eu- and positive Се-anomalies were observed. The high values of the Te/Se, Sr/Ba, Y/Ho, and U/Th indicators in the ores are associated with the deposit location in the zone of granitoid massif effect. Further, the physical and chemical parameters of ore formation in the Teply area are unusual and are characterized by high temperatures, low concentrations of salts, and fluid density, which are indicative of the typical “dry steam” conditions. The obtained results allow the Primorskoye epithermal deposit to be attributed to the intermediate class. The information present in the article is practically valuable for the regional forecast and metallogenic developments as well as for searching and assessing the epithermal Ag-Au deposits.
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Liu, Shiyu, Yuping Liu, Lin Ye, Chen Wei, Yi Cai, and Weihong Chen. "Genesis of Dulong Sn-Zn-In Polymetallic Deposit in Yunnan Province, South China: Insights from Cassiterite U-Pb Ages and Trace Element Compositions." Minerals 11, no. 2 (February 13, 2021): 199. http://dx.doi.org/10.3390/min11020199.
Full textAbstract:
The Dulong Sn-Zn-In polymetallic deposit in the Yunnan province, SW China, hosts a reserve of 5.0 Mt Zn, 0.4 Mt Sn, and 7 Kt In. It is one of the most important polymetallic tin ore districts in China. Granites at Dulong mining area include mainly the Laojunshan granite (third phase), which occurs as quartz porphyry or granite porphyry dikes in the Southern edge of the Laojunshan intrusive complex. Granites of phases one and two are intersected at drill holes at depth. There are three types of cassiterite mineralization developed in the deposit: cassiterite-magnetite ± sulfide ore (Cst I), cassiterite-sulfide ore (Cst II) within the proximal skarn in contact with the concealed granite (granites of phases one to two and three), and cassiterite-quartz vein ore (Cst III) near porphyritic granite. Field geology and petrographic studies indicate that acid neutralising muscovitization and pyroxene reactions were part of mechanisms for Sn precipitation resulting from fluid-rock interaction. In situ U–Pb dating of cassiterite samples from the ore stages of cassiterite-sulfide (Cst II) and Cassiterite-quartz vein (Cst III) yielded Tera-Wasserburg U–Pb lower intercept ages of 88.5 ± 2.1 Ma and 82.1 ± 6.3 Ma, respectively. The two mineralization ages are consistent with the emplacement age of the Laojunshan granite (75.9–92.9 Ma) within error, suggesting a close temporal link between Sn-Zn(-In) mineralization and granitic magmatism. LA-ICPMS trace element study of cassiterite indicates that tetravalent elements (such as Zr, Hf, Ti, U, W) are incorporated in cassiterite by direct substitution, and the trivalent element (Fe) is replaced by coupled substitution. CL image shows that the fluorescence signal of Cst I–II is greater than that of Cst III, which is caused by differences in contents of activating luminescence elements (Al, Ti, W, etc.) and quenching luminescence element (Fe). Elevated W and Fe but lowered Zr, Hf, Nb, and Ta concentrations of the three type cassiterites from the Dulong Sn-Zn-In polymetallic deposit are distinctly different from those of cassiterites in VMS/SEDEX tin deposits, but similar to those from granite-related tin deposits. From cassiterite-magnetite ± sulfide (Cst I), cassiterite-sulfide ore (Cst II), to cassiterite-quartz vein ore-stage (Cst III), high field strength elements (HFSEs: Zr, Nb, Ta, Hf) decrease. This fact combined with cassiterite crystallization ages, indicates that Cst I–II mainly related to concealed granite (Laojunshan granites of phases one and two) while Cst III is mainly related to porphyritic granite (Laojunshan granites of phase three).
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Slack, John F., Leonid A. Neymark, Richard J. Moscati, Heather A. Lowers, Paul W. Ransom, Robert L. Hauser, and David T. Adams. "Origin of Tin Mineralization in the Sullivan Pb-Zn-Ag Deposit, British Columbia: Constraints from Textures, Geochemistry, and LA-ICP-MS U-Pb Geochronology of Cassiterite." Economic Geology 115, no. 8 (August 24, 2020): 1699–724. http://dx.doi.org/10.5382/econgeo.4761.
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Abstract Textural, geochronological, and geochemical data are presented here for cassiterite from the giant (149.7 million tonnes [Mt]) Mesoproterozoic Sullivan Pb-Zn-Ag deposit, which has been subjected to several tectonothermal events. These data provide constraints on the age and origin of the tin concentrations and new insights into related base metal mineralization. Sullivan is rare among sediment-hosted, stratiform Pb-Zn-Ag deposits in having high tin contents in ore (up to 2.5 wt %; avg 310 ppm Sn). Cassiterite occurs in all facies of this deformed and metamorphosed deposit, including (1) high-grade veins with arsenopyrite and pyrrhotite, (2) bedded Pb-Zn-Ag ores, (3) massive pyrrhotite, (4) footwall and hanging-wall tourmalinites, and (5) other altered wall rocks. New in situ U-Pb dates for Sullivan cassiterite obtained by laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) are modeled by a multicomponent-based algorithm that yields three age peaks: 1475 ± 4 Ma (51% of the data), 1366 ± 10 Ma (25%), and 1074 ± 7 Ma (24%). These dates are attributed, respectively, to primary tin mineralization at ca. 1475 Ma, the East Kootenay orogeny at ca. 1370 to 1300 Ma, and the Grenvillian orogeny at ca. 1100 to 980 Ma. Based on the presence and local abundance of cassiterite in all ore and ore-related rocks at Sullivan, the U-Pb date of 1475 ± 4 Ma reported here represents the first direct age for ore mineralization in the deposit. Occurrence of texturally discordant rims on Sullivan cassiterite grains having U-Pb dates coeval with the East Kootenay and Grenvillian orogenies suggests that these young dates reflect dissolution-reprecipitation processes associated with channelized metamorphic fluid flow. LA-ICP-MS U-Pb dates obtained on low-U (<10 ppm) cassiterite also indicate that U-Pb dates for cassiterite from other metamorphosed deposits should be viewed with caution and not assumed to record an age of primary tin mineralization. Aqueous transport conditions for tin are evaluated to gain insights into the cassiterite mineralization at Sullivan. Based on fO2-pH topology of aqueous tin species at 250°C, tin transport was dominated by an SnCl3− complex at fO2 of about –40 and pH of <4.0, conditions that were constrained, respectively, by widespread occurrence of pyrrhotite in deep footwall siliciclastic metasedimentary rocks of the host Aldridge Formation and by release of CO2 from shallow mafic sills and resulting formation of carbonic acid in condensed brine. The low fO2 value also reflects inferred production of CH4 from heating of organic matter in the sediments during emplacement of these sills. Based on a fluid pH restriction of <4.0 and a requirement for sparse or no K-feldspar in the source, the tin likely derives from previously altered Lower Aldridge strata. This model relies on the early diagenetic dissolution of K-feldspar from these sediments by basinal brines, followed by interaction with a later, more acidic hydrothermal fluid generated during the emplacement of large mafic sills in the shallow subsurface that leached tin from accessory minerals such as titanite in siliciclastic sediments of the Lower Aldridge Formation. Mass balance calculations suggest that derivation of the tin from this sedimentary source (avg 2.0 ppm Sn) required ~40 km3 and a cylinder diameter of 3.2 km (height 5.0 km) in order to supply the 0.1 Mt of tin contained in the deposit. The presence of mafic sills in the footwall of several other tin-bearing, sediment-hosted, stratiform Pb-Zn-Ag deposits and in modern, tin-rich, sediment-hosted sulfide deposits in the northeast Pacific Ocean suggests that siliciclastic marine basins that contain mafic sills—with or without stratiform sulfide deposits—should be evaluated for possible tin mineralization.
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Toulhoat, Pierre, and Catherine Beaucaire. "Géochimie des eaux liées au gisement d'uranium de Cigar Lake (Saskatchewan, Canada) et apport des isotopes de l'uranium et du plomb comme guides de prospection." Canadian Journal of Earth Sciences 30, no. 4 (April 1, 1993): 754–63. http://dx.doi.org/10.1139/e93-061.
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The primary objective of this study is a better understanding of the chemical evolution of the waters crossing the Cigar Lake (Saskatchewan, Canada) uranium ore deposit and, once described, to investigate the behavior of the lead and uranium isotopes and to test their use as guidelines in exploration. The underground waters around the Cigar Lake ore deposit were sampled by pumping bore holes or by air lifting. Isotopic analyses of U and Pb and chemical analyses of the major elements and of some trace elements (Ba, Ra, U) were completed. Based on these results, a model is proposed to explain the genesis and evolution of the waters and also to account for the water–minerals equilibria. The saturation indices of uraninite and coffinite were determined by way of oxidation–reduction potentials calculated on the basis of measured Fe contents. The waters saturated with these minerals, which are also the most reduced, are systematically located directly above or across the ore deposit. These saturation indices, as well as the calculated oxidation–reduction potentials, are good guidelines for hydrogeochemical exploration in the Cigar Lake orebody setting; however, they must be used only in a relative fashion. Furthermore, the 234U/238U disequilibrium measurements and the U concentration in the waters permit the recognition of waters having percolated through the mineralized zones (higher U concentrations, lower disequilibria). The nature of the mineralization is probably responsible for the coexistence of the two evolutionary trends within the mineralized zones; in the high-grade zones, the disequilibria are low, whereas in the zones of disseminated mineralization or in halos surrounding the orebody, the disequilibria are greater, reflecting the prevailing influence of selective dissolution of 234U in the zones where exchange surfaces between the mineral carrying U and the solution are more important. The measurement of Pb isotopic ratios in the waters also permits of a clear characterization of waters that have percolated through the ore deposit: in this case, the Pb isotopic ratios are enriched in radiogenic Pb. [Journal Translation]
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Xu, Junwei, Xianghua Liu, Jianqing Lai, Hongsheng He, Xiangfa Song, Degao Zhai, Bin Li, Yuhua Wang, Jian Shi, and Xi Zhou. "In Situ U-Pb Geochronology of Calcite from the World’s Largest Antimony Deposit at Xikuangshan, Southern China." Minerals 12, no. 7 (July 18, 2022): 899. http://dx.doi.org/10.3390/min12070899.
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The Xikuangshan antimony (Sb) deposit is the world’s largest known Sb deposit. Due to the lack of suitable minerals for reliable high-precision radiometric dating, it remains difficult to determine the exact age of Sb mineralization in this deposit. Here, we report the first LA-MC-ICP-MS U-Pb ages of syn-stibnite calcite from this deposit. The dating results indicate the presence of at least two stages of Sb mineralization in the Xikuangshan ore district. The calcite-stibnite veins in the Daocaowan ore block probably formed during the Paleocene (58.1 ± 0.9 Ma), representing an early stage of Sb mineralization, while the quartz-stibnite vein in the Feishuiyan ore block probably formed during the Eocene (50.4 ± 4.4 Ma, 50.4 ± 5.0 Ma, and 51.9 ± 1.6 Ma), representing a late stage of Sb mineralization. The new calcite U-Pb ages are significantly younger than the calcite Sm-Nd ages (124.1 ± 3.7 Ma, 155.5 ± 1.1 Ma) reported by previous researchers. We suggest that Sb mineralization of the South China antimony metallogenic belt may be related to tectono-thermal events during Paleogene, possibly linked to high heat flow during the subduction (ca. 60–40 Ma) of the Pacific Plate beneath the Eurasian Plate and/or the Indo–Asian Collision (began at ca. 61 Ma). The young in situ U-Pb ages of calcite challenge the idea of late Mesozoic Sb mineralization in the South China antimony metallogenic belt, suggesting the requirement for more high-precision dating studies.
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Fox, David C. M., Samuel C. Spinks, Milo Barham, Christopher L. Kirkland, Mark A. Pearce, Mehrooz Aspandiar, Renee Birchall, and Ed Mead. "Working up an Apatite: Enigmatic Mesoarchean Hydrothermal Cu-Co-Au Mineralization in the Pilbara Craton." Economic Geology 116, no. 7 (November 1, 2021): 1561–73. http://dx.doi.org/10.5382/econgeo.4842.
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Abstract Globally, significant examples of hydrothermal Cu-Co mineralization are rare within Archean greenstone belts, especially relative to the endowment of these terranes with other world-class hydrothermal ore deposits, particularly Au deposits. Using U-Pb geochronology of hydrothermal apatite, this study provides the first absolute age constraints on the timing of mineralization for the Carlow Castle Cu-Co-Au deposit. Carlow Castle is a complex, shear zone-hosted, veined Cu-Co-Au mineral system situated within the Paleo-Mesoarchean Roebourne greenstone belt of the Pilbara craton of northwestern Western Australia. Although U-Pb geochronology of this deposit is challenging due to low levels of radiogenic Pb in synmineralization apatite, mineralization is best estimated at 2957 ± 67 Ma (n = 61). Additionally, analysis of alteration phases associated with Carlow Castle mineralization suggests that it is dominated by a propylitic assemblage that is characteristic of alkaline fluid chemistry and peak temperatures >300°C. Within proximal portions of the northwest Pilbara craton, the period of Carlow Castle’s formation constrained here is associated with significant base-metal volcanogenic massive sulfide mineralization and magmatic activity related to back-arc rifting. This rifting and associated magmatic activity are the most likely source of Carlow Castle’s unique Cu-Co-Au mineralization. Carlow Castle’s Mesoarchean mineralization age makes it among the oldest discovered Cu-Co-Au deposits globally, and unique in the broader context of hydrothermal Cu-Co-Au deposits. Globally, hydrothermal Cu-Co mineralization occurs almost exclusively as Proterozoic and Phanerozoic stratiform sediment-hosted Cu-Co deposits due to the necessity of meteorically derived oxidized ore fluids in their formation. This research therefore has implications for exploration for atypical Cu-Co deposits and Cu-Co metallogenesis through recognition of comparably uncommon magmatic-hydrothermal Cu-Co-Au ore-forming processes and, consequently, the potential for analogous Cu-Co-Au mineralization in other Archean greenstone belts.
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Murzintsev, N. G., I. Yu Annikova, A. V. Travin, A. G. Vladimirov, B. A. Dyachkov, V. I. Maslov, T. A. Oitseva, and O. A. Gavryushkina. "THERMOCHRONOLOGY AND MATHEMATICAL MODELING OF THE FORMATION DYNAMICS OF RARE‐METAL‐GRANITE DEPOSITS OF THE ALTAI COLLISION SYSTEM." Geodynamics & Tectonophysics 10, no. 2 (June 24, 2019): 375–404. http://dx.doi.org/10.5800/gt-2019-10-2-0419.
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The article presents an event correlation of the Permian‐Triassic granites of the Altai collision system, which are associated with industrial ore deposits and occurrences (Mo‐W, Sn‐W, Li‐Ta‐Be). The multi‐system and multi‐mineral isotope datings of igneous rocks and ore bodies (U/Pb, Re/Os, Rb/Sr, Ar/Ar‐methods) suggest the postcollisional (intraplate) formation of ore‐magmatic systems (OMS), the duration of which depended on the crustmantle interaction and the rates of tectonic exposure of geoblocks to the upper crustal levels.Two cases of the OMS thermal history are described: (1) Kalguty Mo‐W deposit associated with rare‐metal granite‐leucogranites and ongonite‐ elvan dykes, and (2) Novo‐Akhmirov Li‐Ta deposit represented by topaz‐zinnwaldite granites and the contemporary lamprophyre and ongonit‐elvan dykes. For these geological objects, numerical modeling was carried out. The proposed models show thermal cooling of the deep magmatic chambers of granite composition, resulting in the residual foci of rare‐metal‐granite melts, which are known as the petrological indicators of industrial ore deposits (Mo‐W, Sn‐W, Li‐Ta‐Be). According to the simulation results concerning the framework of a closed magmatic system with a complex multistage development history, the magmatic chamber has a lower underlying observable massif and a reservoir associated with it. A long‐term magmatic differentiation of the parental melt (a source of rare‐metal‐granite melts and ore hydrothermal fluids) takes place in this reservoir.
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Li, Ping, Ting Liang, Fan Huang, Tongyang Zhao, Zhixin Zhu, Yong Li, Jing Feng, and Lei He. "The Metallogeny of the Tieling Cu-Mo Porphyry Deposit in Eastern Tianshan, NW China: New Insights from Zircon U-Pb, Fluid Inclusion, and H-O-S Stable Isotope Analyses." Geofluids 2021 (September 16, 2021): 1–19. http://dx.doi.org/10.1155/2021/5566757.
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The eastern Tianshan metallogenic belt is an important molybdenum resource base in Xinjiang and is characterized by large-scale porphyry Mo deposits formed during the Triassic. The Tieling Cu-Mo porphyry deposit, which is situated in the western part of the eastern Tianshan metallogenic belt, was recently recognized as being related to Carboniferous granite porphyry. Three stages of hydrothermal mineralization were identified, including quartz+K-feldspar+pyrite±molybdenite±magnetite (stage I), quartz+molybdenite+pyrite+chalcopyrite (stage II), and quartz+pyrite±molybdenite±epidote (stage III). Fluid inclusion petrography and microthermometry analyses indicate the presence of gas-liquid inclusions with a H2O-NaCl composition. The ore-forming fluids have a characteristic temperature ranging from 157 to 262°C under stage II and 135 to 173°C under stage III, which correspond to salinities of 7.2-17.2 wt% NaCl equiv. and 5.9 to 9.6 wt% NaCl equiv., respectively. The hydrogen and oxygen isotope data indicate that the ore-forming fluids of the Tieling deposit were originally derived from magmatic hydrothermal fluids and then mixed with meteoric water. The sulfur isotope compositions indicate that the ore-forming materials were mainly derived from the Late Carboniferous felsic magma. Furthermore, zircon U-Pb analysis of ore-bearing granite porphyry yields a concordant age of 298.4 ± 0.7 Ma , indicating that the Tieling Cu-Mo deposit formed during the Late Carboniferous and differed from that processed under pre-Early Carboniferous and Triassic mineralization in the eastern Tianshan metallogenic belt. These results also indicate that the Tieling porphyry deposit was formed in the transition condition between subduction-related accretion and postcollisional orogeny, and it should be given more attention in prospect evaluations.
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Prytchin, M. E., E. I. Soroka, and V. N. Puchkov. "Novel U-Pb isotopic zircon data on the rhyolite of the Saf’yanovskoe Cu-Zn deposit (Middle Urals)." LITHOSPHERE (Russia) 21, no. 6 (December 29, 2021): 884–93. http://dx.doi.org/10.24930/1681-9004-2021-21-6-884-893.
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Research subject. Zircons from the Saf’yanovskoe Cu-Zn deposit rhyolite (Middle Urals). For the first time, zircon U-Pb dating for the rhyolite of the ore-bearing volcanic-sedimentary rocks of the Saf’yanovskoe deposit was performed. The volcanites are characterized by an andesite-rhyodacite composition and are localized at the southern edge of the Rezhevskaya structural-formation zone (SFZ) of the Eastern Ural megazone. A number of publications assign these rocks either to the basalt-rhyolite formation of the Middle Devonian, or to the basalt-andesite-dacite-rhyolite formation of the Lower-Middle Devonian.Aim. To estimate the age of the ore-bearing volcanic rocks under study using the U-Pb SHRIMP-II isotop ic system of zircon from the rhyolite of the eastern side of the Saf’yanovskoe deposit. By its chemical composition, the rhyolite belongs to the silicic varieties of subvolcanic rocks. Methods and results. The U-Pb isotopic system of zircon was studied by 5-collector mass-spectrometer of high precision and emission of the secondary ions SHRIMP-II (ASI, Australia) in the VSЕGEI Institute. U-Pb relations were investigated by a procedure developed by I.S. Williams. The U-Pb data obtained based on 13 zircon grains showed the age of 422.8 ± 3.7 Ma. Conclusions. The U-Pb dating of zircon obtained previously from the lens-shaped andesite bodies of the western side of the Safyanovskoe deposit gave the age of 422.8 Ma, which corresponds to the Przydoli series epoch of the Upper Silurian. We established that, among the volcanic rocks of the Saf’yanovskoe deposit, the effusive formations of the Upper Silurian are present.
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Zhang, Long, Xiaofeng Li, Guo Wang, and Mou Wang. "Direct evidence for the source of uranium in the Baiyanghe deposit from accessory mineral alteration in the Yangzhuang granite porphyry, Xinjiang Province, northwest China." American Mineralogist 105, no. 10 (October 1, 2020): 1556–71. http://dx.doi.org/10.2138/am-2020-7383.
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Abstract Circumstantial evidence for the sources of uranium in ore deposits may be drawn from the study of deposit geochemistry and mineralogy. However, direct evidence supporting uranium leaching from source rocks has rarely been found. This study investigates the source of uranium in the Baiyanghe deposit in the Xiemisitai Mountains, northwest China. The main uranium ore bodies occur as fracture-fillings along contact zones between the Yangzhuang granite porphyry and the Devonian volcanic rocks. Zircon, thorite, columbite-(Mn), and bastnäsite are the dominant accessory minerals that host uranium in the granite porphyry. In situ columbite-(Mn) LA-ICP-MS U-Pb dating yields a weighted mean 206Pb/238U age of 310 ± 4 Ma, suggesting that the Yangzhuang granite porphyry was emplaced during the Late Carboniferous. Backscattered electron (BSE) images reveal that various degrees of alteration of these same accessory minerals may be observed in the granite porphyry, and the altered domains of these minerals have lower BSE intensities compared to the unaltered domains. Results indicate that the altered domains of zircon grains have lower concentrations of Zr, Si, and U, and higher concentrations of Y, Fe, Ca, and P relative to the unaltered domains, and the altered domains of columbite-(Mn) grains are enriched in Ti and Fe and are depleted in Nb, Ta, Mn, U, and Zr. The altered domains of thorite grains have higher concentrations of Zr, Fe, Ca, Nb, and P, and lower Th and U compared to those of the relict domains. The petrochemical data indicate that the granite porphyry experienced losses in U, Be, F, Ba, Sr, Pb, Zr, Mo, Nb, Ta, and Hf during alteration. These results suggest that the past-magmatic hydrothermal fluids might be responsible for the mobilization of uranium form minerals in the granite porphyry. It is concluded that U-bearing accessory minerals in the granite porphyry were the primary source of uranium, and that post-magmatic hydrothermal processes caused remobilization and significant localized enrichment of the uranium to form high-grade ores as fracture-fillings along its contacts.