Ore and Energy Resource Geology最新文献

{"title":"Characterization of heavy minerals and stream sediment from Bidjouka area, Nyong Complex south Cameroon: implications for gold mineralization","authors":"Ndema Mbongué Jean-Lavenir ,&nbsp;Christian Diomo Mukete ,&nbsp;Djomo Michel Cedric ,&nbsp;Peter Namange","doi":"10.1016/j.oreoa.2024.100039","DOIUrl":"https://doi.org/10.1016/j.oreoa.2024.100039","url":null,"abstract":"<div><p>The stream sediment geochemistry has a wide application in mineral exploration. In this study, we applied the stream sediment geochemistry to decipher the primary source of gold mineralization, determine the mineralogy of heavy mineral concentrate and also to ascertain the provenance, depositional environment, intensity of weathering as well as determine the tectonic setting. To investigate heavy mineral in stream channel, 20 placer materials from Bidjouka area were assessed by thin plate using polarized microscope. The powder was further characterized by ICP-MS using aqua regia. Results show that placers displayed minerals such as magnetite, zircon and gold. Majors geochemical base metal point out low grade of iron (&lt; 5 wt.%), titanium (&lt; 1.05 wt.%) and alumina (&lt; 0.60 wt.%). The following metallic trace elements used for industrial technology are identified in the samples. It mainly concerns manganese and thorium with content less than 328 and 200 ppm respectively as well as mercury (&lt; 550 ppb). Precious metals are also present in the chemical composition of Bidjouka sediments. The main substances identified is gold with the grade above 2 g/tone, which is an important target in mining exploration. Also the mean value of rare earth elements varying between 1256.6 and 3626.8 ppm are so speculative, with negative and positive Eu and Ce anomaly respectively. Gold is bound with sulfide mineral (Au-Bi), suggesting a sulfidation event during sediments deposition. Factor 4 (Co, Mn, Sc, Au, Bi) refers to the mineralization factor and Co, Mn, Sc, Bi serve as pathfinder of gold. Sediments were deposited under humid, oxic and oxidizing conditions; intermediate intensity of weathering processes of the source rocks had prevailed during deposition, and sediments were rich in plagioclase. These continental sediments have quartzose sedimentary provenance, they were originated from metamorphic sources and were deposited in an active continental margin. The results of this study serve as guide for gold exploration and exploitation in the Bidjouka area.</p></div>","PeriodicalId":100993,"journal":{"name":"Ore and Energy Resource Geology","volume":"16 ","pages":"Article 100039"},"PeriodicalIF":0.0,"publicationDate":"2024-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139503797","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Comparison of the major- and trace-element compositions of the Kang-dian and Rössing-Husaib uraniferous leucocratic rocks","authors":"Chuanrong Nie ,&nbsp;Lu Xiang ,&nbsp;Zhengqi Xu ,&nbsp;Chongxiao Dai","doi":"10.1016/j.oreoa.2023.100038","DOIUrl":"https://doi.org/10.1016/j.oreoa.2023.100038","url":null,"abstract":"<div><p><span>The Rössing-Husaib area is well-known for its low-grade and large-reserve U deposits hosted by leucogranites. The leucocratic dykes in the Kang-dian area of China resemble the Rössing-Husaib uraniferous leucogranites in occurrences and mineral assemblages, however, it remains disputable if the Rössing-Husaib and Kang-dian leucocratic rocks have consistent U-mineralizing processes. A comparison of the major and trace element data of the leucocratic rocks from both areas may help to better understand the ore-forming mechanisms and provide implications for exploration in the Kang-dian area. The positive correlation between Rb and P</span>₂O₅ contents for the Rössing leucogranite samples is typical of S-type granitoids in spite of the low A/CNK ratios (∼1.0). The Rössing-Husaib uraniferous leucogranites are generally rich in K₂O and Rb, and have high Rb/Sr and Rb/Ba ratios. In contrast, the Kang-dian leucocratic dykes have lower K₂O and Rb contents, and lower Rb/Sr and Rb/Ba ratios, suggesting a clay-poor source. The U contents of the Rössing-Husaib and Kang-dian dyke samples are positively correlated with TiO₂<span><span><span> contents, but show no correlation with Rb/Sr ratios, which is inconsistent with fractional crystallization. Low-degree partial melting of a U-rich </span>protolith may account for primary U enrichment in the leucocratic rocks. The variable major- and trace-element compositions of the Kang-dian dyke samples may reflect wall-rock assimilation and/or alteration to varying degrees, which further enhanced U enrichment. Relatively low Th/U ratios (∼0.1) favored the final crystallization of </span>uraninite<span><span>. The uraniferous leucogranites in the Kang-dian and Rössing-Husaib areas are commonly undeformed and emplaced along regional large faults and/or domes at the late stage of orogeny. We propose that decompression and uplift of basement rocks facilitated the generation of uraniferous melts, and regional large faults provided a pathway for the ascent of leucocratic </span>magma from depth.</span></span></p></div>","PeriodicalId":100993,"journal":{"name":"Ore and Energy Resource Geology","volume":"16 ","pages":"Article 100038"},"PeriodicalIF":0.0,"publicationDate":"2023-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139433672","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Graphite does not function as a direct reducing agent for unconformity-related uranium mineralization – Evidence from the graphitic metapelite-hosted Gryphon uranium deposit, northern Saskatchewan, Canada","authors":"Nahanni Young ,&nbsp;Guoxiang Chi ,&nbsp;Yongxing Liu ,&nbsp;Hao Song","doi":"10.1016/j.oreoa.2023.100028","DOIUrl":"https://doi.org/10.1016/j.oreoa.2023.100028","url":null,"abstract":"<div><p>It is generally agreed that the unconformity-related uranium (URU) deposits in the Athabasca Basin (Canada) resulted from reactions between basin-derived, oxidizing, U⁶⁺-bearing fluids and reducing agents carried by basement-derived fluids or lithologies enriched in reducing elements. Based on the observation that most URU deposits are spatially associated with graphite-rich zones in the basement, it is believed that either the graphite itself or hydrocarbons derived from it acted as major reducing agents for U mineralization. Several previous studies downplayed graphite as a direct reducing agent for U mineralization because few or no direct contacts between uraninite and graphite have been observed. However, it remains skeptical whether or not this is due to insufficient observation, and what happened to the graphite if it was not directly involved in U precipitation. In this study, graphitic metapelite samples were collected from the Gryphon URU deposit for detailed petrographic and Raman spectroscopic study. Two types of graphite were identified, an earlier phase (Gr1) that is parallel and deformed together with the schistosity, and a later phase (Gr2) that is post-deformation, both of which are pre-U mineralization. Thorough microscopic examination confirmed that there is no direct contact between uraninite and graphite in the thin sections. Raman spectroscopic studies of the graphite indicate that the structural order of both Gr1 and Gr2 decreases toward the orebody. These observations indicate that graphite was not a direct reducing agent causing the precipitation of uraninite. Hydrocarbons (mainly CH₄) produced from in situ fluid-graphite reaction was not responsible for the uraninite precipitation either, because such a process would also have produced textures showing replacement of graphite by uraninite. Instead, the graphite initially present in the host rocks that are now occupied by the orebodies was likely dissolved by the hydrothermal fluids ahead of the precipitation of uraninite. The actual reducing agents causing the precipitation of the bulk of uraninite in the orebodies are likely CH₄ derived from ex situ fluid-graphite reaction below the deposit.</p></div>","PeriodicalId":100993,"journal":{"name":"Ore and Energy Resource Geology","volume":"15 ","pages":"Article 100028"},"PeriodicalIF":0.0,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49753247","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Spatiotemporal records of major historical events and human activities in river sediments: A coupled study of heavy metals distribution and lead isotopic dating","authors":"Shipeng Zhang ,&nbsp;Zhe Chen ,&nbsp;Sheng Wang ,&nbsp;Lan Jiang ,&nbsp;Yufei Yuan ,&nbsp;Haoren Zhao ,&nbsp;Chunyu Wang ,&nbsp;Scott S. Hughes ,&nbsp;Yi Huang","doi":"10.1016/j.oreoa.2023.100029","DOIUrl":"https://doi.org/10.1016/j.oreoa.2023.100029","url":null,"abstract":"<div><p>Thirty sediment samples (11 on the surface and 19 from a 55 cm core) collected in the Dadu River, upstream of the Yangtze River, China, were analyzed by ICP-MS and Laser diffraction particle size techniques to determine heavy metal spatial-temporal distribution and particle size characteristics, respectively. The intent was to clarify the impact of human activities such as Pb-Zn mining and exploration on the distribution of potentially toxic elements (As, Cd, Cr, Cu, Pb and Zn) in adjacent fluvial deposits. Moreover, ²¹⁰Pb isotope dating was applied to study the historical variation and distribution of heavy metal pollution in a sedimentary profile in the middle section of the Dadu River. Results suggest that Cd concentration is notably high, exceeding by 16.3 times the soil background value in Sichuan Province, China, which can be intensified by Pb-Zn ore smelting. Surface sediments are mainly composed of silt, accounting for 79% on average, and relatively minor amounts of clay and sand. The fraction of clay in the downstream segments of the Dadu River is significantly higher than that upstream, indicating that the hydrodynamic force in the downstream region is relatively low compared with the upstream flow. Samples in the sedimentary profile, collected at 3 cm intervals, are mainly composed of silty sand, accounting for 75.6%, which comprehensively reflects the strong hydrodynamic force in this area. The results of ²¹⁰Pb dating of these samples indicate three intervals of historical fluctuation in heavy metal concentrations: 1950–1966, 1988–1991 and 1996–2006, respectively, which coincide to significant historical events (the Cultural Revolution, the construction of Pubugou reservoir and local smelting activities, and the implementation of environmental protection policies). Enrichment factor (EF) values of all heavy metals in the profile began to increase after 1994, and relatively high EF values of Cr and Cd indicated a significant enrichment due to increasing anthropogenic activities during this period. Our study demonstrates that anthropogenic activities can be well recorded in sedimentary profiles and provide new insights to retrieving the history of human developments.</p></div>","PeriodicalId":100993,"journal":{"name":"Ore and Energy Resource Geology","volume":"15 ","pages":"Article 100029"},"PeriodicalIF":0.0,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49753230","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Integrating SBAS-InSAR and LSTM for subsidence monitoring and prediction at Hong Kong international airport","authors":"Xianlin Shi ,&nbsp;Jiahong Zhong ,&nbsp;Yong Yin ,&nbsp;Youdong Chen ,&nbsp;Hao Zhou ,&nbsp;Min Wang ,&nbsp;Keren Dai","doi":"10.1016/j.oreoa.2023.100032","DOIUrl":"https://doi.org/10.1016/j.oreoa.2023.100032","url":null,"abstract":"<div><p>Hong Kong International Airport (HKIA) is one of the busiest airports in the world, and much of its land is reclaimed from the sea, making it prone to uneven subsidence of the ground. Monitoring and predicting the subsidence of its surface are crucial for ensuring the operational safety of the airport. This paper firstly obtained the surface subsidence characteristics of the HKIA through applying the Small Baseline Subset Interferometry Synthetic Aperture Radar (SBAS-InSAR) technology, and then the spatial–temporal evolution was analyzed by using the Standard Deviational Ellipse (SDE) method. Moreover, the Long Short-Term Memory (LSTM) was employed to perform surface trend prediction of HKIA. The results show that the HKIA presents different levels of subsidence and uplift, with a maximum average subsidence rate of −64 mm/year and a maximum cumulative subsidence of −199 mm. The comparison between predicted curves and the actual subsidence revealed by InSAR from 2019 to 2023 is highly consistent, with the average absolute error and root mean square error less than 5 mm, and a coefficient of determination greater than 0.99. The LSTM model utilized in this paper can achieve reliable results in subsidence prediction based on time-series InSAR, and provide alternative means for geohazard prediction.</p></div>","PeriodicalId":100993,"journal":{"name":"Ore and Energy Resource Geology","volume":"15 ","pages":"Article 100032"},"PeriodicalIF":0.0,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49766068","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Ore genesis of the Tethyan Himalayan antimony polymetallic metallogenic belt: Constraints from isotope geochemistry","authors":"Yang Li ,&nbsp;Chenghui Wang ,&nbsp;Yubin Li ,&nbsp;Hang Liu ,&nbsp;Xudong Zhang ,&nbsp;Zong Yang ,&nbsp;Mima Puchi ,&nbsp;Gesang Lamu","doi":"10.1016/j.oreoa.2023.100030","DOIUrl":"https://doi.org/10.1016/j.oreoa.2023.100030","url":null,"abstract":"<div><p>The Tethyan Himalayan metallogenic belt is a significant product resulting from the collisional orogeny between the Indian plate and the Eurasian plate. The region experienced three intricate tectonic-magmatic-mineralization stages: the 59–49 Ma Au mineralization stage, the 43–36 Ma Pb–Zn mineralization stage, and the post-collisional (25–0 Ma) Pb–Zn–Sb–Au mineralization stage. Among these, the post-collisional stage represents the most intense period of Pb–Zn–Sb–Au mineralization in the Tethyan Himalayan region. During this period, about 170 Pb, Zn, Sb, Au and Ag deposits (mineral occurrences) with different sizes and complex types were formed. An extensive analysis of isotope geochemical data from antimony polymetallic deposits within the metallogenic belt led to a comprehensive evaluation of the ore-forming fluids and mineralization processes for various deposit types in the belt. The diverse metal element enrichments and various metal deposit types in the metallogenic belt were not formed from a single fluid source. Instead, the ore-forming fluids showed characteristics of fluid mixing from multiple sources. The composition of these fluids primarily comprises formation water, magmatic water, atmospheric precipitation, geothermal water, and metamorphic fluid. However, there were similarities between the different deposit types. Ore-forming materials predominantly come from the crust, although contributions from the mantle to varying degrees have been observed. Deep magmatic fluids or metamorphic fluids within rocks play a crucial role in the ore-forming process. Simultaneously, by establishing the internal relationship between tectonic–magmatic events and Pb–Zn–Sb–Au mineralization, detailed studies on the characteristics of the ore-forming fluid and the ore-forming process were conducted.</p></div>","PeriodicalId":100993,"journal":{"name":"Ore and Energy Resource Geology","volume":"15 ","pages":"Article 100030"},"PeriodicalIF":0.0,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49752967","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Indian carbonatites in the global tectonic context","authors":"Malcolm Aranha ,&nbsp;Alok Porwal ,&nbsp;Ignacio González-Álvarez","doi":"10.1016/j.oreoa.2023.100023","DOIUrl":"https://doi.org/10.1016/j.oreoa.2023.100023","url":null,"abstract":"<div><p>Chrono-tectonic settings of the carbonatite occurrences of India are reviewed with a focus on the “big picture” of carbonatite emplacements in the Indian plate in relation to global tectonic events associated with the amalgamation and breakup of supercontinents. Four chrono-tectonic domains, namely, Southern domain, Southeastern domain, Northeastern domain and Northwestern domain, are delineated based on the geographical distribution, tectonic settings and temporal relationships amongst the carbonatite complexes. The Southern domain comprises two sub-domains – Paleoproterozic and Neoproterozoic. The Paleoproterozoic sub-domain is related to extension due to relaxation after the Southern Granulite Terrain-Dharwar accretion, while the Neoproterozoic sub-domain is related to rifting related to the fragmentation of Rodinia. The Southeastern domain is related to the Mesoproterozoic fragmentation of Columbia. The Northeastern domain is related to the Mid-Cretaceous breakup of Greater India from Australia-Antarctica driven by the Kerguelen mantle plume that also produced the Rajmahal-Sylhet Large Igneous Province (LIP). The Northwestern domain is related to the Late-Cretaceous Indo-Seychelles-Madagascar split and the passage of Greater India over the reunion hotspot, which also produced the Deccan LIP.</p></div>","PeriodicalId":100993,"journal":{"name":"Ore and Energy Resource Geology","volume":"15 ","pages":"Article 100023"},"PeriodicalIF":0.0,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49753059","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Petrogenesis and tectonic implications of the early Paleozoic granites in the Lincang granitic batholith, southwestern China: Constraints from geochronology, geochemistry and Hf isotopes","authors":"Qian R. Xiao ,&nbsp;Qiang Wang ,&nbsp;Zhong Y. Liu ,&nbsp;Fu H. Xiong ,&nbsp;Lei Fan ,&nbsp;Han Zhao ,&nbsp;Ting T. Gong","doi":"10.1016/j.oreoa.2023.100022","DOIUrl":"https://doi.org/10.1016/j.oreoa.2023.100022","url":null,"abstract":"<div><p>This study presents the recently discovered Wulao Shan Ordovician granite within the Lincang granitic batholith, discusses its geochemical affinity, genesis, and tectonic significance, and interprets the proto-Tethys orogenic model in southwest Yunnan. LA-ICP-MS zircon U-Pb analyses indicate a crystalline age of 473.0 ± 2.9 Ma for the Wulaoshan gneissic granite. Geochemical analyses show that the Wulaoshan granite exhibits relatively high SiO₂ concentrations (73.4–77.3 wt.%), strong peraluminous properties (ASI &gt; 1.1), strongly Eu-negative anomalies, light and heavy rare earth fractionation, and relative Ba, Nb, Ta, Sr, P, and Ti depletion. SiO₂ and P₂O₅ exhibit a strong negative correlation, whereas Rb and Y-Th with a positive correlation. The magmatic zircons have negative εHf(t) values of -5.47∼2.74. Petrographic observations and whole-rock geochemical and isotopic analyses imply no aluminum-rich minerals such as cordierite, indicating that the Wulaoshan granite is a highly fractionated, high-temperature I-type granite, which may have formed via partial melting of the magnesian-iron igneous crust. Additionally, K-feldspar, plagioclase, and biotite within the granite samples may have undergone intense fractional crystallization. The Wulao Shan gneissic granite is an arc granite associated with subduction, indicating that the Lincang Block underwent proto-Tethys subduction. This finding provides evidence for proto-Tethys subduction down to the Lincang-Simao block and further supports the bidirectional subduction model of the proto-Tethys.</p></div>","PeriodicalId":100993,"journal":{"name":"Ore and Energy Resource Geology","volume":"15 ","pages":"Article 100022"},"PeriodicalIF":0.0,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49759780","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Environmental impact of artisanal and small-scale gold mining in East Cameroon, Sub-Saharan Africa: An overview","authors":"Mumbfu Ernestine Mimba ,&nbsp;Phebe Ursula Teh Mbafor ,&nbsp;Salomon César Nguemhe Fils ,&nbsp;Melvin Tamnta Nforba","doi":"10.1016/j.oreoa.2023.100031","DOIUrl":"https://doi.org/10.1016/j.oreoa.2023.100031","url":null,"abstract":"<div><p>The East Region of Cameroon is a crucial area for mining activities. Over the past 20 years, there has been growing research into the potential environmental impacts of artisanal and small-scale gold mining (ASGM) in this region. Both in the short and long term, this type of mining can generate numerous health, environmental and socioeconomic impacts that can be measured using diverse methods. This study analyzes impacts of ASGM in some mining districts of this part of Cameroon through literature review. Four categories of mining-induced hazards have been considered: water and stream sediments, soil and mine tailings, health, society, and economy, and land use/cover change. The majority of studies have focused on the impacts on water and soil in the Betare-Oya and Batouri mining areas. Generally, the natural waters of Betare-Oya and Batouri are contaminated in Fe, Mn, Cu, Ni Cr and As, Cr, Pb, V, Zn, respectively. The soils in Betare-Oya are the most impacted by heavy metals due to the artisanal gold mining techniques employed. Point sources of contamination were identified to occur around active and abandoned mine sites. Additionally, socioeconomic and land use/cover risk assessments have been analyzed. The collaboration between different institutions and stakeholders can enhance the development of large databases, expertise, and technology for a better understanding of potential risks in the region and decision making. Finally, the use of GIS-based modeling for the assessment of mining-generated impacts should be expanded in the region. This approach is useful in handling geospatial data related to hazards caused by mining and for ensuring a long-term survey to monitor the evolution of contamination in natural waters, bottom sediments, and soils in the region.</p></div>","PeriodicalId":100993,"journal":{"name":"Ore and Energy Resource Geology","volume":"15 ","pages":"Article 100031"},"PeriodicalIF":0.0,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49766060","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Geology, geochemistry, fluid inclusion microthermometry and depositional environment of the Early Cretaceous Meymeh sub-seafloor replacement sideritic-ankeritic iron deposit, Malayer-Esfahan Metallogenic Belt, Iran","authors":"Rasoul Foroutan-Nia,&nbsp;Sajjad Maghfouri,&nbsp;Ebrahim Rastad","doi":"10.1016/j.oreoa.2023.100033","DOIUrl":"https://doi.org/10.1016/j.oreoa.2023.100033","url":null,"abstract":"<div><p>Meymeh sideritic-ankeritic iron deposit in the eastern part of Malayer-Esfahan Metallogenic Belt (MEMB) is formed in the sedimentary-volcanic rocks of the Early Cretaceous sequence. Ore mineralization in the study area based on stratigraphic location and type of host rocks divided in two ore horizons. Lower ore horizon located in the dolomitic-sandy limestone (Kc₃) unit, which upper ore horizon is formed in thin-bedded limestone (Km) rocks. Petrographic studies indicates that mineralization comprises three ore facies: stockwork, bedded and massive ore facies. The most important primary minerals are siderite, ankerite, ferroan-dolomite, pyrite, pyrolusite, barite and minor chalcopyrite. The most frequent textures in the ore zones include laminae, replacement, vein-veinlet, massive and banded. Dolomitization and silicification are the main wall rock alteration styles; alteration intensity increases towards the ore zones. Based on relationships between ore minerals and rock forming minerals, ore mineralization (hypogene and supergene) in the Meymeh deposit formed during three main stages: fine-grained Fe-carbonate bands are intricately interlayered with dolomite beds. Sideritic-ankeritic bands exhibit classic sedimentary textures, such as laminations and bedding, indicative of a syn-sedimentary to early diagenesis origin. Coarser-grained stage two siderites and ankerites show breccia and vein-veinlet textures, and are considered to have formed by replacement during burial diagenetic sub-seafloor fluid flow. In stage three, siderite and ankerite were converted to secondary iron oxides such as oxide/hydroxide Fe minerals during meteoric water flow through the inverted normal and thrust faults and uplift. The primary two-phase fluid inclusions in the quartz-2 and ankerite-2 minerals that have been investigated from the ore mineralization section of the Meymeh deposit are homogenized at temperatures between 110.3 to 226.9 °C. Salinities of the primary fluid inclusions range from 3.39 wt.% to 14.77 % NaCl eq. This finding suggests that hydrothermal brine fluid mixing with seawater could be the primary mechanism that prompted ore formation. The similarity of REE patterns between siderite and ankerite in different ore facies and host rock carbonates indicates their derivation from the same ore fluids. The Meymeh deposit is considered a typical case of sedimentary hydrothermal diagenetic sideritic-ankeritic mineralization, in which minerals deposited when hydrothermal fluid was released from anoxic to suboxic water columns.</p></div>","PeriodicalId":100993,"journal":{"name":"Ore and Energy Resource Geology","volume":"15 ","pages":"Article 100033"},"PeriodicalIF":0.0,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49727185","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}