scholarly journals Geology and Geochemistry of Selected Gold Deposits in the Ailaoshan Metallogenic Belt, China: Origin of Ore-Forming Fluids

Minerals ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1276
Author(s):  
Yang Li ◽  
Denghong Wang ◽  
Chenghui Wang ◽  
Yan Sun ◽  
MIMA Pu-chi
Keyword(s):  
Host Rock ◽  
Large Scale ◽  
Gold Mineralization ◽  
Mining Area ◽  
Gold Deposits ◽  
Pb Isotopes ◽  
Late Triassic ◽  
Geochemical Data ◽  
Continental Scale ◽  
Metallogenic Belt

The formation of the Ailaoshan metallogenic belt was the result of: the Neoproterozoic super mantle plume, the Indosinian and South China blocks in the Late Triassic after the Paleo-Tethys Ocean closure, and Oligocene-Eocene continental-scale shearing related to the India-Eurasia collision. It is one of the most important Cenozoic gold ore province in the world. In this paper, the geological characteristics, isotopic geochemistry, and geochemical data of ore-forming fluids of four large-scale gold deposits in the Ailaoshan metallogenic belt (Mojiang Jinchang, Zhenyuan Laowangzhai, Yuanyang Daping, and Jinping Chang’an) are comprehensively compared. The features of host-rock alteration, metallogenetic periods and stages, geochronology, fluid inclusion, and C-H-O-S-Pb isotopes of gold deposits are summarized and analyzed. The gold mineralization in the Ailaoshan metallogenic belt occurred mostly in 50–30 Ma, belonging to the Himalayan period. The gold mineralization is closely related to silicification, argillation, carbonation, and pyritization due to the strong mineralization of hydrothermal fluid, the development of alteration products, and the inconspicuous spatial zonation of alteration types. The ore-forming fluid is mainly composed of mantle fluid (magmatic water) and metamorphic fluid (metamorphic water). The ore-forming materials of the Jinchang, Chang’an, and Laowangzhai gold deposits mainly originate the host-rock strata of the mining area, and the carbon is more likely to from marine carbonate. The carbon in the Daping gold deposit from the original magma formed by the partial melting of the mantle. Pb isotopes have characteristics of crustal origin, accompanied by mixing of mantle-derived materials and multisource sulfur mixing, and are strongly homogenized.

Mineral Exploration using CSAMT data: Application to Longmen region metallogenic belt, Guangdong Province, China

Geophysics ◽  
2013 ◽  
Vol 78 (3) ◽  
pp. B111-B119 ◽  
Author(s):  
Xiangyun Hu ◽  
Ronghua Peng ◽  
Guiju Wu ◽  
Weiping Wang ◽  
Guangpu Huo ◽  
...  
Keyword(s):  
Large Scale ◽  
Southern China ◽  
Mineral Exploration ◽  
Geochemical Data ◽  
Data Application ◽  
Metallogenic Belt ◽  
Fe Content ◽  
Geophysical Surveys ◽  
Occam’S Inversion ◽  
Integrated Interpretation

A controlled-source audio-frequency magnetotelluric (CSAMT) survey has been carried out to investigate potential iron (Fe) and polymetallic (Pb-Zn-Cu) deposits in Longmen region, which is one of the main metallogenic belts in southern China. Conducting geophysical surveys in this area is quite difficult due to mountainous terrain, dense forest, and thick vegetation cover. A total of 560 CSAMT soundings were recorded along twelve surveying lines. Two-dimensional Occam’s inversion scheme was used to interpret these CSAMT data. The resulting electric resistivity models showed that three large-scale highly conductive bodies exist within the surveying area. By integrated interpretation combined with available geologic, geophysical, and geochemical data in this area, three prospective mineral deposits were demarcated. Based on the CSAMT results, a borehole penetrating approximately 250-m depth was drilled at the location of 470 m to the northwest end of line 06, defined with a massive pyrite from the depth of 52–235 m with 7%–16% Fe content, as well as locally high-grade Pb-Zn- and Ag-Ti-bearing ores.

scholarly journals Typomorphic Features of Placer Gold from the Billyakh Tectonic Melange Zone of the Anabar Shield and Its Potential Ore Sources (Northeastern Siberian Platform)

Minerals ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 281
Author(s):  
Boris Gerasimov ◽  
Vasily Beryozkin ◽  
Alexander Kravchenko
Keyword(s):  
Native Gold ◽  
Gold Mineralization ◽  
Coarse Fraction ◽  
Gold Deposits ◽  
Primary Sources ◽  
The Arctic ◽  
Geochemical Data ◽  
Placer Gold ◽  
Anabar Shield ◽  
Tectonic Mélange

Precambrian shields and outcropped Precambrian rock complexes in the Arctic may serve as the most important sources of various types of mineral raw materials, including gold. The gold potential of the Anabar shield in the territory of Siberia has, thus far, been poorly studied. A number of primary and placer gold occurrences have been discovered there, but criteria for the prediction of and search for gold mineralization remain unclear. The main purpose of this paper was to study the typomorphic features of placer gold in the central part of the Billyakh tectonic mélange zone in the Anabar shield and to compare them to mineralization from primary sources. To achieve this, we utilized common methods for mineralogical, petrographic, and mineragraphic analyses. Additionally, geochemical data were used. As a result of this investigation, important prospecting guides were identified, and essential criteria for the prediction of and search for gold deposits were elucidated. The characteristics of the studied placer gold were specific for gold derived from a proximal provenance. These characteristics included the poor roundness of the native gold grains, a cloddy–angular and dendritic form, an uneven surface, and a high content of coarse-fraction native gold (0.5–2 mm), which was as high as 24% of the volume of analyzed native gold. In addition, we conducted a study on the mineralogical features of the gold-sulfide mineralization that was disseminated throughout a small exposure area of paleo-Proterozoic para- and orthogneisses in the Anabar shield basement. A comparison of mineral inclusions in the coarse-fraction native gold and mineral assemblages in the ore deposits showed that one of the possible primary sources for placer gold might be small bodies of metasomatically altered orthogneisses associated with large granitoid plutons.

scholarly journals A Geological-Geophysical Prospecting Model for Deep-Seated Gold Deposits in the Jiaodong Peninsula, China

Minerals ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1393
Author(s):  
Mingchun Song ◽  
Guoqiang Xue ◽  
Hongbo Liu ◽  
Yixin Li ◽  
Chunyan He ◽  
...  
Keyword(s):  
Large Scale ◽  
Fault Location ◽  
Geophysical Methods ◽  
Mining Area ◽  
Geological Structure ◽  
Gold Deposits ◽  
Geophysical Prospecting ◽  
Metallogenic Model ◽  
Jiaodong Peninsula ◽  
Frequency Domain Methods

The North China Craton is one of China’s major gold-producing areas. Breakthroughs have been continually made in deep prospecting at depths of 500–2000 m in the Jiaodong Peninsula, and geophysical methods have played an important role. Given that the geophysical signals of deep-seated gold deposits are difficult to detect, due to their thick overburden layers, conventional geophysical methods are not suitable for deep prospecting. Therefore, this study upgrades the geological-geophysical prospecting model, which is based on the deep metallogenic model and geophysical method of large exploration depths. Based on the analysis of the metallogenic geological factors of the altered-rock-type gold deposits in the fracture zones of the Jiaodong Peninsula, this study proposes that the gold deposits are controlled by large-scale faults, generally occur near the contact interfaces between the Early Precambrian metamorphic rock series and Mesozoic granitoids, and exhibit a stepped metallogenic model. This model then becomes the prerequisite and basic condition for deep prospecting by geophysical methods. For this reason, the traditional geophysical model, which focuses on the exploration of shallow mineralization anomalies, is transformed into a comprehensive multi-parameter geological-geophysical qualitative prospecting model highlighting the exploration of ore-controlling structural planes. The model adopts various frequency domain methods (e.g., CSAMT, AMT, WFEM), reflection seismology, and other methods to detect the deep geological structure. The characteristics of parameters such as gravity and magnetism, resistivity, polarizability, and the seismic reflection spectrum are applied to identify the ore-controlling fault location and dip angle change, and to estimate the ore-bearing location according to the stepped metallogenic model. The prospecting demonstration of deep-seated gold deposits in the Shuiwangzhuang mining area indicates the effectiveness of the comprehensive model. The comprehensive deep prospecting model effectively solves the problem of deep prospecting of gold deposits controlled by faults, promotes the great breakthrough of deep prospecting in the Jiaodong Peninsula, and provides an important technology demonstration for deep prospecting throughout China.

scholarly journals Identifying Geochemical Anomalies Associated with Gold Mineralization Using Factor Analysis and Spectrum–Area Multifractal Model in Laowan District, Qinling-Dabie Metallogenic Belt, Central China

Minerals ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 229
Author(s):  
Ruoyu Wu ◽  
Jianli Chen ◽  
Jiangnan Zhao ◽  
Jinduo Chen ◽  
Shouyu Chen
Keyword(s):  
Factor Analysis ◽  
Gold Mineralization ◽  
Fractal Model ◽  
Central China ◽  
Geochemical Data ◽  
Geochemical Anomalies ◽  
Theoretical Support ◽  
Metallogenic Belt ◽  
Spectrum Area ◽  
Anomaly Map

The Laowan deposit is a typical gold deposit in the Qinling-Dabie metallogenic belt, which produces the most gold resources in Central China. After being explored for decades, follow-up exploration requires additional theoretical support. In this study, the factor analysis (FA) and spectrum–area (S–A) multifractal model were used to process multi-element geochemical data from 369 samples collected in the study area for identifying the geochemical anomalies associated with gold mineralization. The results showed that: (1) the mean Au content in this region is up to 1000 times higher than the Au background values of the upper crust of the South Qinling unit; (2) the factor analysis revealed that Au, Ag, Cu, As, Sb, and S can be used as direct ore-prospecting criteria; (3) the observed elemental zonation is consistent with the zonation of metallic elements in the magmatic–hydrothermal system. This supports the magmatic–hydrothermal origin of the Laowan deposit; (4) the spectrum–area fractal model can help to decompose the geochemical patterns in a complex geological setting. The decomposed geochemical anomaly map obtained by the S–A multifractal model indicated that highly anomalous areas have a great relationship with the Au occurrence and can be a guidance for further exploration in the study area.

Magnetic modeling of iron oxide copper-gold mineralization constrained by 3D multiscale integration of petrophysical and geochemical data: Cloncurry District, Australia

2013 ◽  
Vol 1 (1) ◽  
pp. T63-T84 ◽  
Author(s):  
James R. Austin ◽  
Phillip W. Schmidt ◽  
Clive A. Foss
Keyword(s):  
Iron Oxide ◽  
Gold Mineralization ◽  
Signal Amplitude ◽  
Gold Deposits ◽  
Geochemical Data ◽  
Geophysical Investigation ◽  
Structural Controls ◽  
Breccia Pipe ◽  
Copper Gold

Magnetite-rich iron oxide copper-gold deposits (IOCGs) are geologically and geochemically complex and present major challenges to geophysical investigation. They often sit beneath significant cover, exhibit magnetic remanence, and suffer from self-demagnetization effects. Because remanence in magnetite-bearing drill core samples is commonly overprinted by drilling, in situ natural remanent magnetization is difficult to measure accurately, and thus IOCGs cannot be modeled definitively using geophysics alone. We examined structural controls on a magnetite-rich IOCG in northwest Queensland and the relationships between structure, alteration, Fe oxides, and mineralization at core to deposit scale. Magnetite within the deposit has a multidomain structure, and thus it would commonly have an in situ magnetization parallel to the earth’s field. In contrast, pyrrhotite has a pseudosingle-domain structure and so it is the predominant carrier of stable remanence within the ore system. Geophysical lineament analyses are used to determine structural controls on mineralization, geophysical filters (e.g., analytic signal amplitude) are used to help define structural extent of the deposit, and basement geochemistry is used to map mineral footprints beneath cover. These techniques identified coincident anomalies at the intersection of north and northwest lineaments. Leapfrog™ interpolations of downhole magnetic susceptibility and Cu, Au, and Fe assay data were used to map the distribution of magnetite, copper, gold, and sulfur in 3D. The analysis revealed that Cu and Au mineralization were coupled with the magnetite net-vein architecture, but that Cu was locally enriched in the east–northeast-trending demagnetized zone. The results from this suite of geophysical, petrophysical, and geochemical techniques were integrated to constrain modeling of the Brumby IOCG. Brumby can be described as a breccia pipe sitting at the intersection of north-striking, east-dipping, and northwest-striking, southeast-dipping structures that plunges moderately to the south–southeast. The breccia pipe was overprinted by a relatively late net-vein magnetite breccia and crosscut by a later, magnetite-destructive, east–northeast-striking fault.

scholarly journals Significance of Calcite Trace Elements Contents and C-O Isotopic Compositions for Ore-Forming Fluids and Gold Prospecting in the Zhesang Carlin-Like Gold Deposit of Southeastern Yunnan, China

Minerals ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 338
Author(s):  
Jiasheng Wang ◽  
Jinyang Chang ◽  
Chao Li ◽  
Zhenchun Han ◽  
Tao Wang ◽  
...  
Keyword(s):  
Rare Earth ◽  
Rare Earth Elements ◽  
Gold Deposit ◽  
Meteoric Water ◽  
Gold Mineralization ◽  
Mining Area ◽  
Gold Deposits ◽  
Hydrothermal Fluids ◽  
Magmatic Fluid ◽  
Isotopic Compositions

The Zhesang gold deposit of southeastern Yunnan is an important component of the Dian-Qian-Gui (Yunnan, Guizhou, and Guangxi) “Golden Triangle”, which hosts a multitude of Carlin-like gold deposits (CLGDs). Calcite is one of the most common gangue minerals in Zhesang. The calcites that have been found in the mining area are classified as ore-stage and post-ore calcites. The ore-stage calcite exhibits a clear paragenetic relationship with gold-bearing arsenopyrite and with an alteration halo that has been cut by the post-ore calcite. To elucidate the origin of the ore-forming fluids of the Zhesang gold deposit and to investigate the possibility of utilizing calcite geochemistry as prospecting indicators, the rare earth elements (REEs), Y, Fe, Mn and Mg contents, and C-O isotopic compositions of calcites from Zhesang have been analyzed. The ore-stage calcite is enriched in middle rare earth elements (MREEs) relative to light rare earth elements (LREEs) and heavy rare earth elements (HREEs) (MREE/LREE = 1.11–1.61, MREE/HREE = 6.12–8.22), whereas post-ore calcite exhibits an enrichment in LREE (LREE/HREE = 4.39–14.93, MREE/LREE = 0.35–0.71). The ore-stage and post-ore calcites were both formed by hydrothermal fluids; however, these hydrothermal fluids may have different sources. The Fe contents of the ore-stage calcite are significantly higher than those of post-ore calcite (4690–6300 μg/g versus 2030–2730 μg/g). Ore-stage calcite also has significantly lower δ18OV-SMOW values than post-ore calcite (11.03–12.49‰ versus 16.48–17.14‰). These calcites with an MREE/LREE ratio greater than 0.92, MREE/HREE ratio greater than 5.69, Fe content greater than 3827 μg/g, and δ18OV-SMOW value less than 14.40‰ represent ore-stage calcites and are important prospecting guidelines. According to the REE, C-O isotopic characteristics of the calcites and the previous findings, it is inferred that the ore-forming fluids of the Zhesang gold deposit were a mixture of crustal fluid by meteoric water leaching wall rocks and a small amount of basic magmatic fluid. The formation of post-ore calcite might be derived from meteoric water and marine carbonates interaction. The ore-forming fluids of the Zhesang gold deposit may be associated with the intrusion of diabase that outcrops in the mining area, and that the basic magmatic activities of the Indosinian period also provided some of the ore-forming materials and heat for gold mineralization.

scholarly journals AGE OF GOLD MINERALIZATION IN THE YANA-KOLYMA METALLOGENIC BELT, NORTHEAST RUSSIA: FIRST DATA OF RE-OS ISOTOPE GEOCRONOLOGY OF NATIVE GOLD

2021 ◽  
Vol 40 (4) ◽  
pp. 18-32
Author(s):  
V.Yu. Fridovsky ◽  
◽  
N.А. Goryachev ◽  
R.Sh. Krymsky ◽  
M.V. Kudrin ◽  
...  
Keyword(s):  
Native Gold ◽  
Gold Mineralization ◽  
Gold Deposits ◽  
Northeast Russia ◽  
Metallogenic Belt ◽  
Mantle Sources ◽  
First Results ◽  
Isotope System ◽  
Os Isotope

Presented are the first results of studying the Re-Os isotope system of native gold from the orogenic Malo-Taryny, Khangalas, and Bazovsky deposits located in the central part of the Yana-Kolyma metallogenic belt. Re concentration in the sampled gold varies from 0.168 to 6.997 mg/t while that of Os changes from 0.068 to 1.443 mg/t. The data obtained enabled calculation of the isochrone age which is consistent, within the limits of error, with 40Ar-39Ar and К-Аr dates of sericite from the above deposits. The results obtained indicate that gold deposits under study were formed in the interv of 147.8–137.1 Ma synchronously with Late Jurassic – Early Cretaceous orogenic processes in the Yana-Kolyma metallogenic belt and the eastern margin of the Siberian continent. The initial Os isotope ratios ((187Os/188Os)i= 0.1844–0.2475) in the studied samples and fractions of gold from the Malo-Tarynsky, Khangalas and Bazovsky deposits suggest a significant role of a non-radiogenic component, normally associated with mantle sources.

scholarly journals Tracing fluid evolution in sedimentary basins with calcite geochemical, isotopic and U-Pb geochronological data: Implications for petroleum and mineral resource accumulation in the Nanpanjiang Basin, South China

2021 ◽  
Author(s):  
Xiang Ge ◽  
Chuanbo Shen ◽  
Renjie Zhou ◽  
Peng He ◽  
Jianxin Zhao ◽  
...  
Keyword(s):  
Fluid Flow ◽  
South China ◽  
Genetic Model ◽  
Gold Mineralization ◽  
Sedimentary Basins ◽  
Gold Deposits ◽  
Geochemical Data ◽  
Petroleum Migration ◽  
Fluid Evolution ◽  
Flow Activity

Fluid migration in sedimentary basins enable mass and energy transport and play critical roles in geochemical and geodynamical evolution of sedimentary basins. Moreover, reconstructing sedimentary basin fluid evolution from the geological record aids in constraining the evolution of associated petroleum and mineralization systems. As a relict of fluid flow activity, calcite is often a record of fluid flow and therefore can be used to characterize the fluids responsible for its precipitation. Here we study the Nanpanjiang Basin in South China where petroleum reservoirs and Carlin-type gold deposits spatially coincide. Through in situ U-Pb dating and geochemical analysis (87Sr/86Sr, δ18OVienna standard mean ocean water, δ13CVienna Peedee belemnite, rare earth elements) of calcite, this work constrains the key times related to petroleum migration/accumulation and Carlin-type gold mineralization, defines the basin fluid evolution, and proposes a genetic model for petroleum accumulation and gold mineralization within the Nanpanjiang Basin. The U-Pb age (ca. 241.4 Ma) for the gray/black calcite related to bitumen indicates the petroleum migration/accumulation occurred during the Triassic. The U-Pb date (ca. 106−121 Ma) of the white calcite associated with the gold-bearing pyrite, realgar, and fluorite record the lower timing limit of the Carlin-type gold systems. The geochemical data suggest both calcite types are cogenetic but suffered complex evolution with the gray/black calcite precipitating under low temperatures related to the continuous basin burial and the white calcite affected by post formation alteration related to both hydrothermal and meteoric fluids. Combined with the regional tectonic history, the Early Triassic petroleum migration/accumulation and the Early Cretaceous secondary Carlin-type gold mineralization events are considered to be related to the collision between the Indo-China and South China blocks, and the subduction between the Paleo-Pacific and Eurasian plates, respectively.

scholarly journals Quartz Rb-Sr Isochron Ages of Two Type Orebodies from the Nibao Carlin-type Gold Deposit, Guizhou, China

Minerals ◽  
2019 ◽  
Vol 9 (7) ◽  
pp. 399 ◽  
Author(s):  
Zheng ◽  
Yang ◽  
Gao ◽  
Chen ◽  
Liu ◽  
...  
Keyword(s):  
Low Temperature ◽  
Gold Deposit ◽  
Fluid Inclusions ◽  
Large Scale ◽  
Gold Mineralization ◽  
Gold Deposits ◽  
Quartz Veins ◽  
Golden Triangle ◽  
Mineralization Age ◽  
Gold Bearing

The Nibao gold deposit, which includes both fault-controlled and strata-bound gold orebodies, constitutes an important part of the Yunnan–Guizhou–Guangxi “Golden Triangle” region. Defining the mineralization age of these gold orebodies may provide additional evidence for constraining the formation ages of low-temperature orebodies and their metallogenic distribution in South China. Petrographic studies of gold-bearing pyrites and ore-related quartz veins indicate that these pyrites coexist with quartz or filled in vein-like quartz, which suggests a possible genetic relationship between the two from Nibao gold deposit. Minerals chemistry shows that Rb and Sr are usually hosted in fluid inclusions in quartz ranging from 0.0786 to 2.0760 ppm and 0.1703 to 2.1820 ppm, respectively. The Rb–Sr isotopic composition of gold-bearing quartz-hosted fluid inclusions from the Nibao gold deposit were found to have Rb–Sr isochron ages of 142 ± 3 and 141 ± 2 Ma for both fault-controlled and strata-bound orebodies, respectively, adding more evidence to previous studies and thus revealing a regional gold mineralization age of 148–134 Ma. These results also confirm the Middle-Late Yanshanian mineralizing events of Carlin-type gold deposits in Yunnan, Guizhou, and Guangxi Provinces of Southwest China. In addition, previous studies indicated that antimony deposits in the region which were formed at ca. 148–126 Ma have a close affinity with gold deposits. This illustrates that the regional low-temperature hydrothermal gold mineralization is related in space and time to the Yanshanian (ca. 146–115 Ma) magmatic activity. Specifically, the large-scale gold and antimony mineralization are considered to be inherently related to mantle-derived mafic and ultramafic magmatic rocks associated with an extensional tectonic environment. Based on the initial 87Sr/86Sr ratios of 0.70844 ± 0.00022 (2σ) and 0.70862 ± 0.00020 (2σ) for gold-bearing quartz veins from fault-controlled and strata-bound gold orebodies, respectively, at the Nibao gold deposit, as well as the C, H, O, and S isotopic characteristics of gold deposits located in the Golden Triangle region, we suggest that the mantle-derived material can be involved in the formation of the Nibao gold deposit and that the ore-forming fluid can be derived from a mixed crust–mantle source.

scholarly journals Types of Tellurium Mineralization of Gold Deposits of the Aldan Shield (Southern Yakutia, Russia)

Minerals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 698
Author(s):  
Larisa A. Kondratieva ◽  
Galina S. Anisimova ◽  
Veronika N. Kardashevskaia
Keyword(s):  
Large Scale ◽  
Native Gold ◽  
Gold Mineralization ◽  
Aldan Shield ◽  
Original Data ◽  
Gold Deposits ◽  
Ore Deposits ◽  
Gold Content ◽  
Southern Yakutia ◽  
Igneous Activity

The published and original data on the tellurium mineralization of gold ore deposits of the Aldan Shield are systematized and generalized. The gold content is related to hydrothermal-metasomatic processes caused by Mesozoic igneous activity of the region. The formation of tellurides occurred at the very late stages of the generation of gold mineralization of all existing types of metasomatic formations. 29 tellurium minerals, including 16 tellurides, 5 sulfotellurides and 8 tellurates have been identified. Tellurium minerals of two systems predominate: Au-Bi-Te and Au-Ag-Te. Gold is not only in an invisible state in sulfides and in the form of native gold of different fineness, but also is part of a variety of compounds: montbrayite, calaverite, sylvanite, krennerite and petzite. In the gold deposits of the Aldan Shield, three mineral types are distinguished: Au-Ag-Te, Au-Bi-Te, and also a mixed one, which combines the mineralization of both systems. The decrease in the fineness of native gold is consistent with the sequence and temperatures of the formation of Te minerals and associated mineral paragenesis from the epithermal–mesothermal Au-Bi-Te to epithermal Au-Ag-Te. The conducted studies allowed us to determine a wide variety of mineral species and significantly expand the area of distribution of Au-Te mineralization that indicates its large-scale regional occurrence in the Aldan Shield.

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