Ore and Energy Resource Geology最新文献

{"title":"Granitoid characteristics of basement to the U-mineralized Bhima basin: Implications for crustal epizone processes","authors":"Sukanta Goswami ,&nbsp;Shivam Shrivastava ,&nbsp;Chanchal Sarbajna ,&nbsp;Kusum Prakash ,&nbsp;Dheeraj Pande ,&nbsp;D.K. Choudhury","doi":"10.1016/j.oreoa.2023.100027","DOIUrl":"https://doi.org/10.1016/j.oreoa.2023.100027","url":null,"abstract":"<div><p>The Dharwar Craton (DC) is an archive containing a good proportion of ancient records of crustal evolution in its rocks. The greenstone-gneiss-migmatite and granitoid complex show significant variation in terms of time, space and mechanism of emplacement according to tectonics and geodynamic set up. The plutons of the northernmost part of Eastern Dharwar Craton (EDC) are especially recognizable from typical litho-structural attributes. The intensity of regional/burial metamorphism is negligible in these granitoids with versatile nature. Simple and composite plutons are demarcated on the basis of field association with distinguishable petro-mineralogy and geochemical characters. K-metasomatism in pluton is established from petrography with supportive geochemistry. Simple pluton is syenitic in nature unlike the composite plutons with lithological variation from Tonalite-Trondhjemite-Granodiorite (TTG) to alkali feldspar granite. The granitoids are developed from crustal melting during the plate convergence. Post-orogenic nature of syenite is indicated from geochemical data. The sharp contact between the plutons and country rocks indicates significant temperature difference between country rocks and emplaced magma. The characteristic features like brittle deformation dominated structures, sharp contact between emplaced plutons and country rocks, very low grade of regional metamorphism, intensely differentiated nature and absence of diatexitic migmatite indicate a shallow crustal depth of plutonic emplacement. Higher concentration of large ion incompatible elements (e.g., U, Th, K) and associated high heat production imply shallow crustal segment with rocks derived from evolved differentiated magma. The study indicates a depth less than 8 km and temperature condition less than 250°C which correspond to epizone, where uranium remobilization is facilitated.</p></div>","PeriodicalId":100993,"journal":{"name":"Ore and Energy Resource Geology","volume":"15 ","pages":"Article 100027"},"PeriodicalIF":0.0,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49727495","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":"Geochemical and mineralogical evaluation of Libale iron- rich manganese deposit, North-central Nigeria","authors":"N.G. Obaje ,&nbsp;U.A. Hassan ,&nbsp;S.O. Idakwo","doi":"10.1016/j.oreoa.2023.100024","DOIUrl":"https://doi.org/10.1016/j.oreoa.2023.100024","url":null,"abstract":"<div><p>The iron-rich manganese deposits of Libale area is located within the basement complex of North-central Nigeria. Mineralogically, the major mineral phases are: goethite (Fe₂O₃.H₂O), spessartine (Mn₃²⁺Al₂(SiO₄)₃), hematite (Fe₂O₃), and quartz (SiO₂), while minor mineral phases are orthoclase (Al₂O₃.K₂O.6 SiO₂), illite (KAl₂Si₃AlO₁₀(OH)₂), and manganite (Mn₂O₃.H₂O) suggesting a trend of mineral assemblage attributed to the differential mineralization of the iron-manganese deposit that may have been caused by the geochemical tectonic activity during its formation. Geochemically, on average, the Fe₂O₃, SiO₂, Al₂O₃, CaO, P₂O₅ content are 34.59 wt.%; 26.30 wt.%; 6.94 wt%, 2.60 wt%, 2.01 wt% correspondently while K₂O and TiO₂ are less than 1wt%. Suggesting oxide facies type for the deposit. The trace element composition of V (1040 ppm), Cr (100 ppm), Co (833.33 ppm), Cu (1740 ppm), Nb (1280 ppm), W (240 ppm), Ta (320 ppm) and Zr (302 ppm) were relatively high compared to Maro, Muro and Kakun BIFs in North-central Nigeria. Bivariate plot of Fe₂O₃ Vs. Al₂O₃, suggest enrichment of Fe₂O₃ but depleted in SiO₂ and Al₂O₃, which possibly indicates replacement of precursor silica and kaolinite with goethite which are subsequently dehydrated to hematite. Al₂O₃-SiO₂-Fe₂O₃ ternary diagram indicates Precambrian Banded Iron Formation (BIF) for the Libale iron- rich manganese deposits, this was confirmed by MnO Vs. FeO. Discriminative plots: FeO. SiO₂ - (FeO + MnO) - Fe₂O₃ and Al₂O₃+ K₂O + Na₂O Vs. MnO + FeO confirmed mixed facies as the analyzed data plots between silicate facies and magnetic-silicate facies, this is linked to chemical association between Al₂O₃ and SiO₂ for the iron-rich as it confirms a transitional grade of silicate facies to magnetite-silicate facies. SiO₂ Vs. Al₂O₃ plot revealed hydrothermal and diagenetic processes for its deposition. The iron-rich manganese deposit is of low grade iron (Av. Fe=24.19%) characterized by ferruginous manganese (Av. MnO₂=23.82%) based on the generalized percentages of element of major interest in assessing quality of iron and manganese ore, therefore, good for cast iron production.</p></div>","PeriodicalId":100993,"journal":{"name":"Ore and Energy Resource Geology","volume":"15 ","pages":"Article 100024"},"PeriodicalIF":0.0,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49752870","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":"Reservoir characteristics and controlling factors of Permian glutenite in Northern Zhongghai uplift, Junggar Basin, China","authors":"Shahab Aman e Room ,&nbsp;Chen Zhonghong ,&nbsp;Hassanat Ullah ,&nbsp;Waqar Ahmad ,&nbsp;Mubarik Ali","doi":"10.1016/j.oreoa.2023.100025","DOIUrl":"https://doi.org/10.1016/j.oreoa.2023.100025","url":null,"abstract":"<div><p>The Permian Sandstone is well preserved in the Junggar Basin, China. It is consisting of fine to medium sandstone with interbedded shale. The present study is focused on to evaluate the reservoir characteristics and controlling factors of the Permian sandstone of Jinlong 51 well, Junggar basin, China. To fulfil the objectives of the current study, geological field, petrographic analysis, SEM, analysis, mercury injection capillary pressure, and progressed geochemical analysis has been used to evaluate the characteristics and diagenetic history of the Permian sandstone to evaluate its potential. Thin section analysis shows that rock comprises of medium to fine-grained lithic sandstone, and glutenite. Pores are primary isolated into intergranular pores, intergranular pores and intra granular pores. The SEM analysis reveals that the major diagenesis types are compaction, cementation, dissolution, and fractures. Rock is moderately compacted, with intermediate cementation as well as feldspar, rock fragment and carbonate cement dissolution. According to core NMR analysis evaluated as low porosity, low permeability of the reservoirs, some of them are low porosity and low permeability reservoirs. The mercury injection capillary pressure shows that pore throat is intermediate pores with moderate pore throat. Permian sandstone consisting of average porosity 17.8% and permeability is from 5.2 to 8 mD, which recommended that the studied formation consisting of moderate reservoir characteristics. Compaction, cementation and fractures fills with clastic material decreases, whereas primary intergranular pores, dissolution pores and fractures increases the reservoir quality. Finally, the impact of diagenesis on the physical properties of the reservoirs under study has been investigated, the compactions and cementation along with other constrains effect the porosity as well as permeability of the glutenite reservoirs.</p></div>","PeriodicalId":100993,"journal":{"name":"Ore and Energy Resource Geology","volume":"15 ","pages":"Article 100025"},"PeriodicalIF":0.0,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49753294","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":"Analysis on multi period activity and evolution of Yingxiu-Beichuan fault in Longmenshan area","authors":"Ding Xiao ,&nbsp;Li Zhongquan ,&nbsp;Li Dian ,&nbsp;Hu Yiling ,&nbsp;Long Wei ,&nbsp;Li Jianing ,&nbsp;Liu Henglin","doi":"10.1016/j.oreoa.2023.100021","DOIUrl":"10.1016/j.oreoa.2023.100021","url":null,"abstract":"<div><p>As the boundary between the Yangtze Craton and the Qinghai-Tibet Plateau, the Longmenshan tectonic belt is known for its typical fault-slip systems and strong Cenozoic activities. Due to the complexity of the structure of the orogenic belt, the tectonic evolution and formation mechanism of the Longmenshan tectonic belt have been controversial. This paper essentially focuses on the geological isotopic chronology limitation of the fault activity of the Longmenshan Central Fault (Yingxiu-Beichuan Fault). The K-Ar dating of the illite in the fault gouge sample on the fault surface reveals that the direct age of the fault would be about 111 Ma. Combined with the previous age results, the following results are obtained: The Yingxiu-Beichuan fault was a multi-stage active fault in the Mesozoic, which was active in the Late Triassic (229–216 Ma), Early Jurassic (190–171 Ma) and the end of Early Cretaceous (130–110Ma). This paper analyzes the evolution of the central fault through regional geological evolution, seismic profile analysis and structural physical simulation experiment, and the following main results are obtained: Animaqing Paleo-Tethys Ocean on the northern margin of the Songpan Garze Block and the Jinshajiang Paleo Tethys Ocean in the southern margin were closed successively in the Middle and Late Triassic, Such a fact essentially occurred under the influence of differential uplift, that is, the pre-existing Yingxiu-Beichuan fault changed from a normal fault to a reverse fault in the Late Triassic, and then reactivated. Under the influence of the gravity slip mechanism, the Yingxiu-Beichuan fault was active until it ceased in the Early Jurassic. Since then, affected by the closure of the Middle Tethys Ocean, in the Early Cretaceous, the fault developed again, and branch faults developed in front of the fault. During the Himalayan period, due to the collision and ccocnnection of the Eurasian plate and the Indian plate, the fault was reactivated.</p></div>","PeriodicalId":100993,"journal":{"name":"Ore and Energy Resource Geology","volume":"15 ","pages":"Article 100021"},"PeriodicalIF":0.0,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2666261223000032/pdfft?md5=7d618183b1053bf1e30fee9b27d5862a&pid=1-s2.0-S2666261223000032-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89866040","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Comparisons of age estimates from Strontium-isotope values versus other Chronostratigraphy methods","authors":"Pengcheng Cai,&nbsp;Xinchun Liu,&nbsp;Lijun Yang,&nbsp;Xue Yan,&nbsp;Liting Wu","doi":"10.1016/j.oreoa.2023.100026","DOIUrl":"https://doi.org/10.1016/j.oreoa.2023.100026","url":null,"abstract":"<div><p>Strontium-isotope stratigraphy enables estimates of numerical dates for marine carbonate-bearing sediments by comparing their ⁸⁷Sr/⁸⁶Sr ratio to a reference curve of ⁸⁷Sr/⁸⁶Sr variations of global seawater through geologic time. That seawater reference curve is a published statistical LOWESS fit to a very large dataset (ca. 14,000) of ⁸⁷Sr/⁸⁶Sr measurements of carbonate fossils from known biozones which is converted to numerical ages using published timescales. In this study, we compute the numerical dates projected by this method for suites ⁸⁷Sr/⁸⁶Sr ratios from seven stratigraphic sections ranging from Ordovician through Oligocene. The strontium-isotope stratigraphy from the Dawangou section in Tarim Basin of NW China that hosts the Auxiliary GSSP for the base of the Late Ordovician is a new dataset; and the others are published datasets. These ⁸⁷Sr/⁸⁶Sr-derived dates are compared to those estimated for the same horizons in these sections by other chronostratigraphic methods, including cyclostratigraphy calibrated to radioisotopic dates and standard biochronostratigraphy. Except for a published study of Lower Triassic strata from Chaohu section in Anhui, China and Middle Devonian strata Jebel Mech Lrdane section of Morocco, all the ⁸⁷Sr/⁸⁶Sr-derived dates are within the estimated uncertainties of the dates from the other chronostratigraphic methods, thereby validating the usefulness of strontium-isotope stratigraphy as one tool for obtaining the ages of marine carbonate-bearing deposits. However, the datasets from all three Paleozoic sections (two Ordovician, one Devonian) did display a noticeable offset bias toward older ages, which may be partly an artifact of inadequate adjustment of the LOWESS reference curve to current age models for the biozones. The ⁸⁷Sr/⁸⁶Sr-derived dates from Chaohu section of Early Triassic conodont zones were unacceptably systematically younger by ca. 1.45 Myr; thereby indicating higher-than-expected ⁸⁷Sr/⁸⁶Sr values, which may have been partially the result of a combination of a semi-restricted basin that was slightly diluted by ⁸⁷Sr-enriched fluvial waters from the chemical weathering of adjacent landmasses and of the laser ablation (LA-ICP-MS) analytical method applied to those samples that seems to yield higher ⁸⁷Sr/⁸⁶Sr ratios than the solution-mode ICP-MS method for ⁸⁷Sr/⁸⁶Sr measurements. In summary, with rare exceptions, the method of strontium-isotope stratigraphy and the statistical ⁸⁷Sr/⁸⁶Sr seawater curve is an important method to obtain semi-precise numerical dates from marine carbonate sediments.</p></div>","PeriodicalId":100993,"journal":{"name":"Ore and Energy Resource Geology","volume":"15 ","pages":"Article 100026"},"PeriodicalIF":0.0,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49753065","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":"Petrography, lithostratigraphy, and geochemistry of iron formations from Toko-Nlokeng area (northwestern Congo craton): Implications for origin, depositional tectonic setting, and potential iron ore resource deposit","authors":"Yannick Saturnin Evina Aboula,&nbsp;Damien Henri Odigui Ahanda,&nbsp;Paul-Désiré Ndjigui,&nbsp;Joseph Mvondo Ondoa","doi":"10.1016/j.oreoa.2023.100020","DOIUrl":"https://doi.org/10.1016/j.oreoa.2023.100020","url":null,"abstract":"<div><p>The genesis of the ore-forming material, the depositional environment, the Fe enrichment process, and the resource estimation of the Toko-Nlokeng iron deposit in the Nyong Complex of southern Cameroon were studied using detailed field investigations, petrography, lithostratigraphy, and geochemical analyses, and deposit modeling methods. This study shows a case of coexistence of granular and banded iron formations (65% GIFs and 35% BIFs) in an Algoma-type deposit, both in the Nyong Complex and worldwide. Representative samples of IFs were collected from drillcores. The Iron Formations (IFs) were associated with metavolcanic rocks consisting of garnet amphibolite, garnet-bearing gneiss, hornblendite, and mafic granulite, which underwent several episodes of deformation and metamorphism of amphibolite to granulite facies. The lithostratigraphic results show sharp correlations between the lithological units of the IFs. The bulk chemistry exhibits SiO₂ and Fe₂O₃ content similar to that of most Archean IFs worldwide, with SiO₂+Fe₂O₃T ranging between 96.31 and 98.10 wt%. Positive Eu anomalies (&gt; 1.8) for BIFs and their association with metavolcanic rocks are consistent with Algoma type IFs. Geochemical data show that the IFs precipitated from a mixture of seawater and high-temperature (&lt; 0.1%) hydrothermal fluids in a submarine environment with volcanic activity under relatively low oxygen conditions. Large amounts of iron and silica were likely produced under these conditions. Thus, the deposition of the Toko-Nlokeng IFs probably involved an iron-rich environment of Fe²⁺-rich hydrothermal fluid in chemically stratified seawater. The block models estimated for TNF08 and TNF11 are constrained by robust geological models of the IFs mineralization with a total measured Mineral Resource estimate of 19.1 Mt grading 36.44% Fe and an Indicated Mineral Resource estimate of 113.6 Mt grading 34.79% Fe. The Toko-Nlokeng can be a reasonable prospect for eventual economic extraction. It is suggested that the transformation of the low-grade IFs protolith into high-grade iron ore was controlled by deformation and metamorphic events.</p></div>","PeriodicalId":100993,"journal":{"name":"Ore and Energy Resource Geology","volume":"14 ","pages":"Article 100020"},"PeriodicalIF":0.0,"publicationDate":"2023-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49750710","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":"A new classification of barite deposits in China","authors":"Yang Li ,&nbsp;Hao Zou ,&nbsp;Nuru Said ,&nbsp;Hang Liu","doi":"10.1016/j.oreoa.2023.100019","DOIUrl":"https://doi.org/10.1016/j.oreoa.2023.100019","url":null,"abstract":"<div><p>A new classification of barite deposits is proposed based on a study of the distribution, ore types, geological characteristics, ore-forming material sources, ore-forming temperatures, and metallogenic models of barite deposits in China. The deposits are divided into five types, sedimentary, hydrothermal, stratabound hydrothermal vein, volcano-sedimentary, and weathering (eluvium–talus) types, with each having a distinct mineralization model. These deposits formed in continental-rift, back-arc-basin, and intracontinental-uplift tectonic environments. Barite ore bodies are stratabound or veined and are most common in Cambrian, Devonian, and Mesozoic host rocks. Most barite deposits were formed at medium to low temperatures (100–300 °C). Mineralization models for the different types of barite deposit are presented in detail.</p></div>","PeriodicalId":100993,"journal":{"name":"Ore and Energy Resource Geology","volume":"14 ","pages":"Article 100019"},"PeriodicalIF":0.0,"publicationDate":"2023-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49750700","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 body domaining by clustering of multiple-point data events; a case study from the Dalli porphyry copper-gold deposit, central Iran","authors":"Hamed Mohammadi,&nbsp;Sajjad Talesh Hosseini,&nbsp;Omid Asghari,&nbsp;Pouya Asadi Harouni","doi":"10.1016/j.oreoa.2022.100018","DOIUrl":"10.1016/j.oreoa.2022.100018","url":null,"abstract":"<div><p>Partitioning of borehole samples into homogenous attributes and continuous spatial domains, here in called ore body<span><span> domaining, is an important step in mineral resource estimation. Traditional clustering approaches are often resulted in certain domains with poor spatial continuity. Therefore, there is a need to a novel approach to consider the </span>spatial dependency between data locations in clustering analysis. In this research, a certain analysis on multiple-point data events, as a nonparametric higher-order geostatistical approach, is introduced to optimize statistical clustering methods by considering spatial information such as drilling data. Initially, user to extract the n-point data events around each borehole samples defines a fixed spatial n-point template. Then, a dissimilarity matrix is calculated through Euclidean distances between pairs of multiple point data events extracted from the dataset. Next, a multidimensional scaling (MDS) is used to represent the similarity or dissimilarity among samples at a low dimension coordinates matrix. Finally, the matrix obtained from MDS is used as an input of statistical clustering methods to improve its ability in terms of spatial continuity and physical realism. In order to verify the performances of proposed approach, we applied to a 2D synthetic case study and a real case of borehole dataset of the Dalli Cu-Au porphyry. The results were analyzed in terms of statistical contrast among domains and generating the continuous spatial and geological realism domains. Evaluations indicate that the results of the proposed method can be resulted in appropriate continuous spatial domains. In addition, the results of real case study indicated that there was a meaningful compatibility between generated domains from the proposed method and available geological facts.</span></p></div>","PeriodicalId":100993,"journal":{"name":"Ore and Energy Resource Geology","volume":"10 ","pages":"Article 100018"},"PeriodicalIF":0.0,"publicationDate":"2022-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76622843","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 and petrography of the volcanic rocks in the Yakhab area, central Iran","authors":"Kaveh Pazand ,&nbsp;Asghar Ghasemi Bersiani ,&nbsp;Hassan Mohammadnezhad","doi":"10.1016/j.oreoa.2021.100016","DOIUrl":"10.1016/j.oreoa.2021.100016","url":null,"abstract":"<div><p>Eocene to Quaternary volcanic and plutonic rocks are exposed in eastern of Kashan in the Urumieh-Dokhtar magmatic belt that located in the Central Iran structural zone. These volcanic rocks have compositions ranging from basaltic andesites, andesites, rhyolite, dacite, tuff to granidiorites. A total of 100 rock samples were taken and based on petrographic and geochemical studies with field observations volcanic rocks in the Yakhab area were evaluated. Geochemical studies show these rocks are a slightly meta-aluminous to per-aluminous. The rocks have SiO₂ contents ranging between 42% and 75%. The geochemical characteristics of the volcanic rocks show that magma was derived from an enriched lithospheric source and indicated magma derived from lower crust or upper mantle lithosphere.</p></div>","PeriodicalId":100993,"journal":{"name":"Ore and Energy Resource Geology","volume":"9 ","pages":"Article 100016"},"PeriodicalIF":0.0,"publicationDate":"2021-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2666261221000055/pdfft?md5=8b3c77b8bd19c4270ed36d98d9fcb2af&pid=1-s2.0-S2666261221000055-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89487807","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Gold occurrences in copper-magnetite-apatite deposit at Seruwila, Sri Lanka","authors":"Nishika Samarakoon ,&nbsp;Sanjeewa P.K. Malaviarachchi ,&nbsp;Atula Senaratne ,&nbsp;Athula Wijayasinghe","doi":"10.1016/j.oreoa.2021.100014","DOIUrl":"10.1016/j.oreoa.2021.100014","url":null,"abstract":"<div><p>This study presents petrology and evidence for possible gold occurrences in Seruwila copper–iron oxide–apatite (IOA) deposit, hosted in an ultramafic intrusion which is located at the boundary between the Highland and Vijayan complexes, within the intermediate-granitic basement in north-eastern Sri Lanka. The study is complemented with petrological observations and XRD and SEM analysis, respectively, to investigate the petrology/subsurface geology of the deposit and identify possible gold occurrences in the deposit. The ore-bearing rocks are mainly composed of magnetite and apatite in various proportions, hosted in an ultramafic intrusion with cumulate features within the granitic-intermediate basement. The secondary veins contain magnetite, chalcopyrite, pyrrhotite, and pyrite together with apatite and scapolite, tremolite, diopside, and minor actinolite and calcite, serpentinite, anhydrite, or gypsum. The clinopyroxene euhedral crystals show cumulus textures including grain triple junctions and large dihedral angles (∼120°), showing magmatic origin. Texturally two types of amphiboles are identified as coarse-grained (0.5–1 mm), pale green euhedral amphibole that is free of inclusions, and fine-grained (&lt;0.1 mm) and brownish, occurring as anhedral inclusions in clinopyroxene. The deposit contains varying amounts of sulfides in which pyrite is the potential gold carrier in magmatic–hydrothermal processes. By the results of XRD analysis, it is evident that the presence of Au (111), Au (200), Au (220) and Au (311), although with low count values (50–500), probably due to the low concentration of gold. Therefore, particularly in the samples with veins or veinlets, gold was inferred to be present in pyrite/chalcopyrite as invisible structurally-bonded gold and/or gold nanoparticles. Hence, the results of this study, although at non-ore grade, veinlets of gold-bearing pyrite/chalcopyrite may serve as a promising target for gold occurrence, being a potential site of gold-mineralization in the context of the East-Gondwana.</p></div>","PeriodicalId":100993,"journal":{"name":"Ore and Energy Resource Geology","volume":"8 ","pages":"Article 100014"},"PeriodicalIF":0.0,"publicationDate":"2021-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/j.oreoa.2021.100014","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"92471567","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}