Application of Structural Analysis in Studies on Genesis and Exploration of Ore Deposits

A special issue of Minerals (ISSN 2075-163X). This special issue belongs to the section "Mineral Exploration Methods and Applications".

Deadline for manuscript submissions: closed (20 March 2023) | Viewed by 26737

Special Issue Editors

Key Laboratory of Metallogenic Prediction of Nonferrous Metals and Geological Environment Monitoring, Ministry of Education, School of Geosciences and Info-Physics, Central South University, Changsha 410083, China
Interests: W-Sn-Nb-Ta and Cu-Pb-Zn mineralization; vein-type Sb-Au; gold mineralization
Special Issues, Collections and Topics in MDPI journals
Key Laboratory of Metallogenic Prediction of Nonferrous Metals and Geological Environment Monitoring, Ministry of Education, School of Geosciences and Info-Physics, Central South University, Changsha 410083, China
Interests: structural analysis; deformation localization

Special Issue Information

Dear Colleagues,

Structural analysis is critical to decipher the ore genesis and determine the exploration target of variable ore deposits. Structural controls are demonstrated for numerous deposit types, such as lode gold, copper–gold, epithermal gold, iron, magnetite, manganese, molybdenum, nickel, sediment-hosted copper, silver–zinc–lead, tungsten, uranium, VHMS, and SHMS. The list illustrates how widely applicable the structural analysis is, even in manganese and nickel laterite deposits, where structural controls are not commonly considered. At present, the application of structural analysis in the field of economic geology mainly focuses on two aspects. First, the formation process of ore deposits from the perspective of structural geology and tectonics, including hydrothermal fluid flow and mineral precipitation driven by tectonism, structural controls on both magmatic intrusions and associated mineralization, and thermodynamic analysis of deformation and mineralization related to non-equilibrium conditions. Second, delineation of ore bodies that aims to build accurate representations of structures, ore bodies, and geochemical or geophysical data, such as geometrical modeling, mechanical modeling, digital technologies for mapping and visualization, and drilling. This Special Issue focuses on recent advances in structural analysis related to genesis and exploration of ore deposits, including but not limited to topics of the listed classic ones. All cases that could give new insights into the theory and application of structural geology and economic geology may represent significant contributions to this Special Issue.

Prof. Dr. Huan Li
Dr. Han Zheng
Guest Editors

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Keywords

  • structural control
  • deformation and mineralization
  • magmatism, hydrothermal fluid flow
  • modeling

Published Papers (10 papers)

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Research

20 pages, 9852 KiB  
Article
Structure–Fluid–Mineralization System of Jiadi Gold Deposit in Southwestern Guizhou, China
by Zhuang Min, Wengao Zhang, Jiayong Pan, Zhenju Zhou, Hailong Huo and Guangwen Huang
Minerals 2023, 13(7), 896; https://doi.org/10.3390/min13070896 - 30 Jun 2023
Viewed by 825
Abstract
The Jiadi gold deposit, situated in the Southwestern region of Guizhou, is a large-scale, recently discovered, basalt-hosted, and fine-grained disseminated gold deposit. This study has unveiled that the tectonic deformation of the Jiadi gold deposit can be categorized into four stages: the Late [...] Read more.
The Jiadi gold deposit, situated in the Southwestern region of Guizhou, is a large-scale, recently discovered, basalt-hosted, and fine-grained disseminated gold deposit. This study has unveiled that the tectonic deformation of the Jiadi gold deposit can be categorized into four stages: the Late Paleozoic crustal uplift and brittle deformation (D1-deformation) stage; the Early Yanshanian NW-trending compressive ductile deformation (D2-deformation) stage; the Late Yanshanian NS-trending strike-slip fault (D3-deformation) stage; and the Himalayan EW-trending nappe structure (D4-deformation) stage. The outcomes of the C-O isotope analysis revealed that the fluid responsible for ore formation exhibits the attributes of magmatic water blended with meteoric water, and the metallogenic constituents primarily originate from a deep source. The formation of the Jiadi gold deposit occurred during the D2-deformation stage and extended to the D3-deformation stage. The D2-deformation stage induced hydrothermal activity and rock devolatilization, leading to the generation of CO2-rich and low-salinity fluids. The D3-deformation stage, which is intimately associated with mineralization, can be classified into three stages: the pyrite stage; the smoky quartz stage; and the sulfide stage. The findings obtained from laser Raman spectroscopy indicate that the inclusions typically comprise CO2, CH4, N2, and SO2. These deep fluids ascended along the fault to the interlayer fracture zone during the D3-deformation stage. The alteration of the geochemical environment was accompanied by fluid immiscibility or boiling, resulting in the rapid precipitation of metallogenic materials. Full article
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26 pages, 26280 KiB  
Article
The Missing Link in the Genesis of the Lower Paleozoic Copper Deposits of the Anti-Atlas (Morocco): The Late Triassic Central Atlantic Magmatic Province Event
by Mohammed Ouchchen, El Hassan Abia, Abderrahmane Soulaimani, Mohamed Abioui, Brandon Lutz, Mohammed Benssaou, Kamal Abdelrahman, Tamer Abu-Alam, Fatima Zahra Echogdali and Said Boutaleb
Minerals 2023, 13(4), 488; https://doi.org/10.3390/min13040488 - 30 Mar 2023
Cited by 3 | Viewed by 2095
Abstract
Copper mineralization in the Lower Paleozoic sedimentary cover of the Anti-Atlas (Morocco) is continually being revised not only to improve its mining capacity, but also to determine its origin, which remains a matter of debate. As evidenced by the various models proposed, the [...] Read more.
Copper mineralization in the Lower Paleozoic sedimentary cover of the Anti-Atlas (Morocco) is continually being revised not only to improve its mining capacity, but also to determine its origin, which remains a matter of debate. As evidenced by the various models proposed, the related research is fragmented, localized, and confusing. The origin of the Anti-Atlas Lower Paleozoic copper mineralization is shared between synergistic and epigenetic processes or a superposition of the two processes. Based on new tectono-magmatic data and a reinterpretation of the ore structural arrangement, we propose a link between the last concentration of copper deposits and the Late Triassic–Early Liassic CAMP (Central Atlantic Magmatic Province) tectono-thermal event, as evidenced by the significant concentration of copper mineralization in the three NE–SW corridors affected by extensional faults, some of which are filled with dolerite CAMP magma. The heat flow generated by the mafic dykes within these reactivated corridors causes mineralized fluids to up well into the sedimentary layers, depositing material rich in juvenile or leached copper, or even a mixture of the two. In some cases, these fluids are trapped by fracture systems that accompany passive folds initiated on normal faults. In other cases, these fluids can infiltrate bedding planes, and even karst caves, formed during carbonate exhumation. Notably, extensive NE–SW faults systematically cover the early Hercynian structures, suggesting that they belong to a post-Hercynian extensional episode. During the Late Triassic, the global fragmentation of the Pangaea supercontinent was manifested by the stretching of the continental crust at the margin of northwest Africa, with the simultaneous opening of the Central Atlantic Ocean and emplacement of CAMP magmatism. This last and often overlooked tectonothermal event must be considered in the remobilization and reconcentration of copper mineralization and other mineralization in Morocco. Full article
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22 pages, 28360 KiB  
Article
Structural Analysis and Paleostress Evolution in the Imiter Silver Mining Region, Eastern Anti Atlas, Morocco: Implications for Mineral Exploration
by Youssef Atif, Abderrahmane Soulaimani, Abdelhak Ait Lahna, Driss Yaagoub, Nasrrddine Youbi, Amin Beiranvand Pour and Mazlan Hashim
Minerals 2022, 12(12), 1563; https://doi.org/10.3390/min12121563 - 04 Dec 2022
Cited by 3 | Viewed by 2118
Abstract
Development and concentration of many ore deposits at the regional and district scales closely depend on structural geology, especially in polydeformed basements. The superposition of many deformation periods highlights the complexity of the structural context and expected potential location of mineralization zones. The [...] Read more.
Development and concentration of many ore deposits at the regional and district scales closely depend on structural geology, especially in polydeformed basements. The superposition of many deformation periods highlights the complexity of the structural context and expected potential location of mineralization zones. The formation and concentration of hydrothermal ore deposits is highly dependent on structural controls. On the NE flank of the Saghro massif (Eastern Anti-Atlas, Morocco), the Imiter silver mining region has been affected by multiple tectonic events since the Precambrian and throughout the Phanerozoic. In this investigation, a structural analysis of the different geological units revealed multi-stage deformation, beginning with the late Pan-African-Cadomian event, and ending with the last Cenozoic exhumation of the area. At least eight tectonic regimes have been identified. The Imiter basement, formed by the Cryogenian-early Ediacaran “flysch-like” Saghro Group, has been folded in low-grade metamorphic conditions, followed by an ENE-WSW brittle compressive event. These deformations occurred before to the early Ediacaran during the compressional and/or transpressional late Pan-African-Cadomian events (600–580 Ma). The unconformably overlaying deposition of the late Ediacaran Ouarzazate Group takes place in a WNW-ESE extensional setting and then involved in a NNW-SSE compressional event that occurred concurrently with a regional exhumation and erosion stages. A similar extensional event appears to have controlled the middle Cambrian sedimentation, the oldest Paleozoic deposits in this area. During the late Carboniferous, Variscan shortening was recorded by NW-SE transpressional deformation responsible for combined dextral strike-slip and southward thrusts. The Imiter silver mining region is part of the Moroccan Sub-Meseta Zone along with Paleozoic inliers of the Skoura and Tamlelt on the southern side of the High Atlas. The Mesozoic evolution began with the Late Triassic NNW-SSW transtensional tectonic regime with a northeast trending CAMP (Central Atlantic Magmatic Province) dyke during the Pangea breakup. Ultimately, the Imiter silver mining region experienced NNW-SSE Atlasic shortening during the uplift of the adjacent High Atlas. Over time, the direction of implemented tectonic stress and its effect on various geological units can elucidate the relationship between tectonism and hydrothermal silver mineralization in the Imiter region. In conclusion, structural analysis and investigation of paleostress development can be one of the most important factors for successful exploration plan and resource recovery in the Imiter region. An analysis of geological structures in determining feasible mineralization zones is crucial for future safe mining operation in the study area and can be extrapolated to other ore mining regions. Full article
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19 pages, 16182 KiB  
Article
Field Observations and Geophysical Research Applied to the Detection of Manganese (Mn) Deposits in the Eastern Part of Oban Massif, South-Eastern Nigeria: An Integrated Approach
by Emmanuel E. Okon, Ebenezer A. Kudamnya, Kehinde D. Oyeyemi, Benjamin O. Omang, Omotayo Ojo and Mohamed Metwaly
Minerals 2022, 12(10), 1250; https://doi.org/10.3390/min12101250 - 30 Sep 2022
Cited by 2 | Viewed by 3495
Abstract
The growing need for an industrialized world, especially in Africa, cannot be feasible without adequate mineral resources. Thus, the search for more mineral deposits will continue to be necessary. An integrated approach involving geological mapping and a high-resolution geophysical (aeromagnetic) investigation was conducted [...] Read more.
The growing need for an industrialized world, especially in Africa, cannot be feasible without adequate mineral resources. Thus, the search for more mineral deposits will continue to be necessary. An integrated approach involving geological mapping and a high-resolution geophysical (aeromagnetic) investigation was conducted to assess the manganese mineralization in parts of the Oban Massif, southeast Nigeria. The aeromagnetic data were processed using regional-residual anomaly separation techniques, first vertical derivative (1VD), analytical signals, source parameters imaging (SPI), and Euler deconvolution to better understand magnetic source distributions and their depths of occurrence. The geological investigation revealed a dominant variety of metamorphic rock types, including migmatitic (banded) gneisses hornblende granite gneisses, amphibolites, charnockites, and some quartzite ridges. Also present are some indications of pockets of dolerites. The study area also observed epithermal Mn+Fe+Qtz vein type mineralization associated with hydrothermal alteration zones whose orientation coincides with dominant structural orientation from aeromagnetic interpretation. Analysis of aeromagnetic data shows that the study area is dominated by ENE, NNE, and E-W structural directions (near-surface basement structures), with the ENE trends related to mineralization in the area. The manganese mineralization within Oban Massif is structurally controlled. The depths of the magnetic anomalies in the study area were estimated using SPI and Euler decomposition algorithms. SPI delineated the shallow, intermediate, and deep magnetic anomalies at 84–142 m, 152–200 m, and 215–656 m, respectively. Euler decomposition, however, revealed that shallow, intermediate, and deep depths occurrence of the magnetic anomalies are at 200–377 m, 393–472 m, and 499–793 m, respectively. Full article
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16 pages, 8572 KiB  
Article
Velocity Structure and Cu-Au Mineralization of the Duobaoshan Ore District, NE China: Constrained by First-Arrival Seismic Tomography
by Zongdong Pan, Hesheng Hou, Wei Fu, Xiaofan Deng, Jiaduo Zhang and Hengcheng Ying
Minerals 2022, 12(8), 959; https://doi.org/10.3390/min12080959 - 28 Jul 2022
Viewed by 2161
Abstract
The genesis of deeply buried deposits in the Duobaoshan ore district, the largest porphyry-related Cu-Mo-Au ore field in northeastern China, is not well understood and their exploration is lacking because the fine velocity structure of this region is not comprehensively understood. Herein, first-arrival [...] Read more.
The genesis of deeply buried deposits in the Duobaoshan ore district, the largest porphyry-related Cu-Mo-Au ore field in northeastern China, is not well understood and their exploration is lacking because the fine velocity structure of this region is not comprehensively understood. Herein, first-arrival seismic travel times were picked along a deep seismic reflection profile and inverted using the tomographic method to obtain a detailed velocity profile of the upper 2900 m of the crust beneath this region. The profile showed that the velocity varied from 1900 to 6100 m/s and that the crust was subdivided into five parts by two low-velocity (2500–4000 m/s) blocks. Based on previous studies, the boundaries between the high-speed and low-speed bodies were interpreted as hidden fractures, and the 5000–6100 m/s parts were interpreted as concealed granite bodies in these sections. Porphyry copper deposits in the Duobaoshan ore district were related to the occulted granite bodies, and epithermal Au deposits were associated with the occulted fracture zones. Comprehensive evaluation of hydrothermal activity, regional magnetic anomalies, and deposit distribution indicated that the hidden fractures served as channels for ore-related magmas. Combining previous research on the Duobaoshan ore district with our results of the high-velocity interface, we infer that the prospecting range of the Tongshan deposit is below the depth of 1000 m. Full article
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18 pages, 8028 KiB  
Article
Structural Controls on Mineralization within the Huanggou Gold Deposit in the Southern Mesozoic Xuefengshan Orogen, South China
by Yuhua Xie, Hua Gao, Hua Kong and Han Zheng
Minerals 2022, 12(6), 751; https://doi.org/10.3390/min12060751 - 14 Jun 2022
Cited by 3 | Viewed by 2338
Abstract
The Mesozoic Xuefengshan Orogen (XFSO) in South China hosts abundant gold ore deposits. The XFSO records a history of polyphase tectonic deformation and the structural controls on gold mineralization are poorly understood. The recently discovered quartz-vein type Huanggou gold deposit in the southern [...] Read more.
The Mesozoic Xuefengshan Orogen (XFSO) in South China hosts abundant gold ore deposits. The XFSO records a history of polyphase tectonic deformation and the structural controls on gold mineralization are poorly understood. The recently discovered quartz-vein type Huanggou gold deposit in the southern XFSO is characterized by multiple stages of deformation and represents an excellent natural laboratory for deciphering structural controls on gold mineralization in a complex orogenic belt. A systematic structural analysis indicates that the geometry of the Huanggou gold deposit and adjacent areas mainly resulted from four stages of deformation: (1) D1 top-to-the-NW sense of shearing; (2) D2 SE-directed back-folding and back-thrusting; (3) D3 NW–SE upright folding; and (4) D4 NW–SE normal faulting and fracturing. Two sets of quartz veins are exposed in the deposit: (1) SE-dipping Au-bearing quartz veins; and (2) NW-dipping non-mineralized quartz veins. The SE-dipping Au-bearing quartz veins were likely formed by the main deformation phase of the XFSO. During D1 top-to-the-NW simple shearing, these synkinematic Au-bearing quartz veins progressively evolved into sigmoidal shapes and rotated to a preferred SE-dipping orientation. Subsequently, D2 SE-directed back-folding and back-thrusting resulted in the formation of synkinematic NW-dipping non-mineralized quartz veins. D3 upright folding locally steepened the dips of both Au-bearing and non-mineralized quartz veins. Our results may provide new insights into the structural controls of gold mineralization in the XFSO. Full article
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29 pages, 15108 KiB  
Article
Structural Setting of the Sixtymile Gold District, Yukon, Canada: Insights into Regional Deformation and Mineralization from Field Mapping and 3D Magnetic Inversion
by Jeremy Rimando, Alexander L. Peace, Meixia Geng, Jacob Verbaas and Harley Slade
Minerals 2022, 12(3), 291; https://doi.org/10.3390/min12030291 - 25 Feb 2022
Cited by 1 | Viewed by 2827
Abstract
The Sixtymile gold district, Yukon, Canada has been mined for placer gold since the late 19th century. However, increasing demand for gold has prompted exploration of new lode deposits. Previous studies in the nearby Klondike gold district have shown correlation between placer deposits [...] Read more.
The Sixtymile gold district, Yukon, Canada has been mined for placer gold since the late 19th century. However, increasing demand for gold has prompted exploration of new lode deposits. Previous studies in the nearby Klondike gold district have shown correlation between placer deposits and bedrock occurrences. Poor bedrock exposure and a complex deformation history, however, make it difficult to determine structural controls on gold mineralization. Through structural analysis involving mesoscopic-scale field observations of fractures, faults, foliation, and folds, and 3D geophysical inversion, the goal of this study was to determine the structural setting of the Sixtymile district to enhance discovery success. Structural measurements in the Glacier Creek, Miller Creek, Bedrock Creek, and Sixtymile River areas show the relationships among the orientations of foliation, fractures, and veins. In most localities, veins are found both parallel and at high angles to foliation, and there is generally a weaker correlation between fractures and veins compared to between foliation and veins. This correlation between foliation and veins is corroborated by inferred gold-bearing horizons from gold assay data. Outcrops of oblique reverse and strike-slip faults, possibly related to a larger-scale thrust-zone, and to the left-lateral Sixtymile-Pika Fault, respectively, were documented for the first time in this study. The results of the 3D probabilistic inversion of total magnetic intensity data for magnetic susceptibility show that magnetic susceptibility highs are preferentially associated with volcanics, but also point to possible intrusive bodies or hydrothermal alteration zones associated with mineralization. A geologic cross-section through the lithologies demonstrates highly variable deformation styles, including extensive folding, possibly indicative of a multiphase deformational history necessitating further, more detailed investigations of the area. Full article
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24 pages, 8892 KiB  
Article
Passive Structural Control on Skarn Mineralization Localization: A Case Study from the Variscan Rosas Shear Zone (SW Sardinia, Italy)
by Fabrizio Cocco, Antonio Attardi, Matteo Luca Deidda, Dario Fancello, Antonio Funedda and Stefano Naitza
Minerals 2022, 12(2), 272; https://doi.org/10.3390/min12020272 - 21 Feb 2022
Cited by 6 | Viewed by 3192
Abstract
The case study presented here deals with the Pb-Zn-Cu skarn ores hosted in the Rosas Shear Zone (RSZ), a highly strained domain located in the external zone of the Sardinian Variscan chain. The RSZ is characterized by several tectonic slices of Cambrian limestones [...] Read more.
The case study presented here deals with the Pb-Zn-Cu skarn ores hosted in the Rosas Shear Zone (RSZ), a highly strained domain located in the external zone of the Sardinian Variscan chain. The RSZ is characterized by several tectonic slices of Cambrian limestones within a strongly folded and foliated Cambrian-Ordovician siliciclastic succession, intruded by late Variscan granites and mafic dykes. Based on geological mapping, structural and microscope analyses, our results show that the skarn ores in the RSZ are an example of passive structurally controlled mineralization. The RSZ was structured close to the brittle–ductile transition and, once exhumed to shallower crustal levels, acted as plumbing system favoring a large-scale granite-related fluid circulation. The paragenesis and the mineralization style of the skarn vary slightly according to the peculiarity of the local structural setting: a tectonic slice adjacent to the mafic dyke; an intensely sheared zone or a discrete thrust surface. Full article
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16 pages, 11141 KiB  
Article
Application and Significance of Geological, Geochemical, and Geophysical Methods in the Nanpo Gold Field in Laos
by Jie Gan, Hui Li, Zhengwei He, Yu Gan, Junqing Mu, Huan Liu and Lin Wang
Minerals 2022, 12(1), 96; https://doi.org/10.3390/min12010096 - 14 Jan 2022
Cited by 7 | Viewed by 2579
Abstract
As the main part of the Indosinian metallogenic province in the eastern part of the Tethys metallogenic domain, Southeast Asia has experienced multiple stages of tectonic magnetic activities accompanied by the formation of rich mineral resources. However, due to the undeveloped economy, low [...] Read more.
As the main part of the Indosinian metallogenic province in the eastern part of the Tethys metallogenic domain, Southeast Asia has experienced multiple stages of tectonic magnetic activities accompanied by the formation of rich mineral resources. However, due to the undeveloped economy, low degree of geological work, dense vegetation cover, and lack of obvious prospecting marks, traditional geological prospecting work in the area is not optimal. Consequently, the combination of high-precision geophysics and geochemistry has become an important method of looking for ore bodies deep underground in this area. The Nanpo gold deposit is a hydrothermal gold deposit that occurs in the Indosinian felsic volcanic rock body, and its mineralization is closely related to felsic magmatism. This study carried out comprehensive geophysical and geochemical exploration methods of soil geochemical survey, induced polarization (IP) survey, and audio-frequency magnetotelluric (AMT) survey. Based on the characteristics of geophysical and geochemical anomalies, geological inference, and interpretation, the integrated geophysical and geochemical prospecting criteria of the ore area have been determined: The large-scale and overlapping Au-Ag-Cu anomaly area in the host felsic magmatic rocks (mainly diorite, monzodiorite and granodiorite) is a favorable metallogenic area. Two anomalies, P1–H1 and P3–H6, with the best metallogenetic conditions and the deepest extensions of the known ore bodies, were further selected as engineering verification targets. After the study of the drill core, gold (mineralized) bodies consistent with the anomalies were found, indicating that the combined method is suitable for the exploration of mineral resources in this area, and the prospecting effect is good. At the same time, the metallogenic prediction shows that the deep part of the mining area still has great metallogenic prospects and prospecting potential. The characteristics of geophysical and geochemical anomalies and prospecting experience in the study area can provide references for the prospecting of hydrothermal gold deposits in the Luang Prabang–Loei structural belt. Full article
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19 pages, 10069 KiB  
Article
Mineralization and Structural Controls of the AB-Bid Carbonate-Hosted Pb-Zn (±Cu) Deposit, Tabas-Posht e Badam Metallogenic Belt, Iran
by Abdorrahman Rajabi, Carles Canet, Pura Alfonso, Pouria Mahmoodi, Ali Yarmohammadi, Shahba Sharifi, Amir Mahdavi and Somaye Rezaei
Minerals 2022, 12(1), 95; https://doi.org/10.3390/min12010095 - 14 Jan 2022
Cited by 2 | Viewed by 2829
Abstract
The Ab-Bid deposit, located in the Tabas-Posht e Badam metallogenic belt (TPMB) in Central Iran, is the largest Pb-Zn (±Cu) deposit in the Behadad-Kuhbanan mining district. Sulfide mineralization in the Ab-Bid deposit formed in Middle Triassic carbonate rocks and contains galena and sphalerite [...] Read more.
The Ab-Bid deposit, located in the Tabas-Posht e Badam metallogenic belt (TPMB) in Central Iran, is the largest Pb-Zn (±Cu) deposit in the Behadad-Kuhbanan mining district. Sulfide mineralization in the Ab-Bid deposit formed in Middle Triassic carbonate rocks and contains galena and sphalerite with minor pyrite, chalcopyrite, chalcocite, and barite. Silicification and dolomitization are the main wall-rock alteration styles. Structural and textural observations indicate that the mineralization occurs as fault fills with coarse-textured, brecciated, and replacement sulfides deposited in a bookshelf structure. The Ab-Bid ore minerals precipitated from high temperature (≈180–200 °C) basinal brines within the dolomitized and silicified carbonates. The sulfur isotope values of ore sulfides suggest a predominant thermochemical sulfate reduction (TSR) process, and the sulfur source was probably Triassic-Jurassic seawater sulfate. Given the current evidence, mineralization at Ab-Bid resulted from focusing of heated, over-pressurized brines of modified basinal origin into an active fault system. The association of the sulfide mineralization with intensely altered wall rock represents a typical example of such features in the Mississippi Valley-type (MVT) metallogenic domain of the TPMB. According to the structural data, the critical ore control is a bookshelf structure having mineralized dextral strike-slip faults in the northern part of the Ab-Bid reverse fault, which seems to be part of a sinistral brittle shear zone. Structural relationships also indicate that the strata-bound, fault-controlled Ab-Bid deposit was formed after the Middle Jurassic, and its formation may be related to compressive and deformation stages of the Mid-Cimmerian in the Middle Jurassic to Laramide orogenic cycle in the Late Cretaceous-Tertiary. Full article
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