Pub Date : 2022-03-29DOI: 10.1080/25726838.2022.2053376
Thomas Mulja
ABSTRACT A reassessment of the geochemistry of stream sediments collected by the British-led North Sumatra Project from 1975 to 1980 in central Aceh with spectrum–area and local singularity fractal techniques refines previously determined areas with anomalous Cu and delineates As anomalies (proxy for Au) that correspond to porphyry Cu and epithermal Au–Ag deposits and prospects discovered in the 1980s and 1990s. Additionally, the application of these methods to stream sediment samples collected by an Australian company in the mid-1990s from part of central Aceh identifies Au, As, and Cu anomalies that are aligned with regional geochemical trends. Integrating singularity metal-enriched areas and the distribution of mineral occurrences and structures reveals northerly and easterly tectono-magmatic corridors controlling epithermal Au–Ag and porphyry Cu mineralisation. The above results attest to the usefulness of legacy data for first-pass mineral assessments and for providing evidence layers for a future mineral prospectivity map.
{"title":"Toward a mineral potential map of central Aceh, North Sumatra: contributions from spectrum-area and local singularity fractal analysis of stream sediment geochemistry and its relationships to magmatic-hydrothermal Cu and Au mineralisation","authors":"Thomas Mulja","doi":"10.1080/25726838.2022.2053376","DOIUrl":"https://doi.org/10.1080/25726838.2022.2053376","url":null,"abstract":"ABSTRACT A reassessment of the geochemistry of stream sediments collected by the British-led North Sumatra Project from 1975 to 1980 in central Aceh with spectrum–area and local singularity fractal techniques refines previously determined areas with anomalous Cu and delineates As anomalies (proxy for Au) that correspond to porphyry Cu and epithermal Au–Ag deposits and prospects discovered in the 1980s and 1990s. Additionally, the application of these methods to stream sediment samples collected by an Australian company in the mid-1990s from part of central Aceh identifies Au, As, and Cu anomalies that are aligned with regional geochemical trends. Integrating singularity metal-enriched areas and the distribution of mineral occurrences and structures reveals northerly and easterly tectono-magmatic corridors controlling epithermal Au–Ag and porphyry Cu mineralisation. The above results attest to the usefulness of legacy data for first-pass mineral assessments and for providing evidence layers for a future mineral prospectivity map.","PeriodicalId":43298,"journal":{"name":"Applied Earth Science-Transactions of the Institutions of Mining and Metallurgy","volume":"131 1","pages":"50 - 68"},"PeriodicalIF":1.0,"publicationDate":"2022-03-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44595416","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}
Pub Date : 2022-03-22DOI: 10.1080/25726838.2022.2054176
S. D. de Oliveira, Ignácio Torresi, Debora A. L. Rossi
ABSTRACT The Palmeirópolis Zn-Pb-Cu volcanogenic massive sulfide deposit consists of four areas, presenting distinct features regarding host rocks, the geometry of ore bodies, hydrothermal alteration, deformation intensity, and metal proportions. The seven modeled Zn-Pb-Cu ore bodies occur mainly along with the contact between the Mesoproterozoic acid and basic metavolcanics within amphibolite facies. Some characteristics such as the relation of higher Zn-Pb and Cu grades to a higher proportion of acid and basic metavolcanic host rocks respectively, the same metamorphic grade and the gradational contact between volcanic host rocks, and distribution of alteration halo suggest that the original stratigraphy is still preserved. A smooth folding superposing the initial tight folds that define the ore bodies indicates at least two deformation events after the Zn-Pb-Cu mineralisation in the Palmeirópolis deposit. Finally, the geometry of the 3D ore bodies in Palmeirópolis are discussed against other VMS deposits around the world with 3D data available in terms of age, metamorphic, and deformation grades.
{"title":"3D structural control and spatial distribution of Zn-Pb-Cu grades in the Palmeirópolis VMS deposit, Brazil","authors":"S. D. de Oliveira, Ignácio Torresi, Debora A. L. Rossi","doi":"10.1080/25726838.2022.2054176","DOIUrl":"https://doi.org/10.1080/25726838.2022.2054176","url":null,"abstract":"ABSTRACT The Palmeirópolis Zn-Pb-Cu volcanogenic massive sulfide deposit consists of four areas, presenting distinct features regarding host rocks, the geometry of ore bodies, hydrothermal alteration, deformation intensity, and metal proportions. The seven modeled Zn-Pb-Cu ore bodies occur mainly along with the contact between the Mesoproterozoic acid and basic metavolcanics within amphibolite facies. Some characteristics such as the relation of higher Zn-Pb and Cu grades to a higher proportion of acid and basic metavolcanic host rocks respectively, the same metamorphic grade and the gradational contact between volcanic host rocks, and distribution of alteration halo suggest that the original stratigraphy is still preserved. A smooth folding superposing the initial tight folds that define the ore bodies indicates at least two deformation events after the Zn-Pb-Cu mineralisation in the Palmeirópolis deposit. Finally, the geometry of the 3D ore bodies in Palmeirópolis are discussed against other VMS deposits around the world with 3D data available in terms of age, metamorphic, and deformation grades.","PeriodicalId":43298,"journal":{"name":"Applied Earth Science-Transactions of the Institutions of Mining and Metallurgy","volume":"131 1","pages":"69 - 85"},"PeriodicalIF":1.0,"publicationDate":"2022-03-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46467135","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}
Pub Date : 2022-01-02DOI: 10.1080/25726838.2022.2035641
Nick Braun
ABSTRACT Geotechnical logging of drillcore typically includes joint roughness due to its importance in rock mass characterisation. Here we propose digitising the measurement of roughness via a tomography scan. Image processing steps are described for relating the scan to a simple profilometric definition of roughness. The approach is amenable to directional statistical visualisation on a stereoplot.
{"title":"Tomographic scanning of rock joint roughness","authors":"Nick Braun","doi":"10.1080/25726838.2022.2035641","DOIUrl":"https://doi.org/10.1080/25726838.2022.2035641","url":null,"abstract":"ABSTRACT Geotechnical logging of drillcore typically includes joint roughness due to its importance in rock mass characterisation. Here we propose digitising the measurement of roughness via a tomography scan. Image processing steps are described for relating the scan to a simple profilometric definition of roughness. The approach is amenable to directional statistical visualisation on a stereoplot.","PeriodicalId":43298,"journal":{"name":"Applied Earth Science-Transactions of the Institutions of Mining and Metallurgy","volume":"131 1","pages":"27 - 31"},"PeriodicalIF":1.0,"publicationDate":"2022-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48895138","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}
Pub Date : 2022-01-02DOI: 10.1080/25726838.2022.2041151
S. Ghannadpour, A. Hezarkhani
ABSTRACT In this study, by using the algorithm of the U-statistic and fractal methods and combining them with each other, a new combined method as U values fractal model (U-N and U-A) is introduced. Then, the proposed method is employed to determine the boundaries of background and anomalous populations. Results show that in U-N and U-A fractal models, the first fracture boundary is much clearer and more accurate than previous fractal models (C-N and C-A) in the same condition. In U-N model, due to the nature of the U method algorithm, there is a discontinuity as exact threshold between background and anomaly that in U-A model, this does not exist due to the homogenization of U values. In this method, the exact threshold between background and anomaly is determined by U-statistic method and by its combination with the fractal method, in each population, sub-populations are identified more accurately and simply than concentration fractal model.
{"title":"Delineation of geochemical anomalies for mineral exploration using combining U-statistic method and fractal technique: U-N and U-A models","authors":"S. Ghannadpour, A. Hezarkhani","doi":"10.1080/25726838.2022.2041151","DOIUrl":"https://doi.org/10.1080/25726838.2022.2041151","url":null,"abstract":"ABSTRACT\u0000 In this study, by using the algorithm of the U-statistic and fractal methods and combining them with each other, a new combined method as U values fractal model (U-N and U-A) is introduced. Then, the proposed method is employed to determine the boundaries of background and anomalous populations. Results show that in U-N and U-A fractal models, the first fracture boundary is much clearer and more accurate than previous fractal models (C-N and C-A) in the same condition. In U-N model, due to the nature of the U method algorithm, there is a discontinuity as exact threshold between background and anomaly that in U-A model, this does not exist due to the homogenization of U values. In this method, the exact threshold between background and anomaly is determined by U-statistic method and by its combination with the fractal method, in each population, sub-populations are identified more accurately and simply than concentration fractal model.","PeriodicalId":43298,"journal":{"name":"Applied Earth Science-Transactions of the Institutions of Mining and Metallurgy","volume":"131 1","pages":"32 - 48"},"PeriodicalIF":1.0,"publicationDate":"2022-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43270415","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}
Pub Date : 2022-01-02DOI: 10.1080/25726838.2022.2045822
S. Jowitt
Welcome to the first issue of Volume 131 of Applied Earth Science and a new year, albeit with a continuing pandemic. Already this year we have seen significant progress in terms of moving towards more normal circumstances and in-person gatherings and hopefully this will continue throughout 2022. This editorial will be a short one to begin the year, and will consist of a couple of editorial changes. Firstly, Patricia Durance will be stepping down as Co-Editor this year. I just wanted to take the opportunity to thank Patricia for her service to Applied Earth Science during her time as part of the editorial team and wish her luck in future ventures. I will also be stepping down as Editor of Applied Earth Science in January 2023. I have been involved with the journal since 2010, was Co-Editor from 2013 to 2019, and will have been Editor for nearly four years when I step down after taking over from Neil Phillips in 2019. My time with Applied Earth Science has been challenging but very rewarding, and has given me useful insights into scientific publishing and writing, editing, peer-reviewing, and a huge array of different types of scientific research. I’d like to thank the team at Taylor and Francis (and Maney before them) for their efforts on behalf of the journal, my Co-Editors and colleagues on the editorial board, and all of the authors and reviewers who have contributed to the journal over the past 12 years.
{"title":"Editorial","authors":"S. Jowitt","doi":"10.1080/25726838.2022.2045822","DOIUrl":"https://doi.org/10.1080/25726838.2022.2045822","url":null,"abstract":"Welcome to the first issue of Volume 131 of Applied Earth Science and a new year, albeit with a continuing pandemic. Already this year we have seen significant progress in terms of moving towards more normal circumstances and in-person gatherings and hopefully this will continue throughout 2022. This editorial will be a short one to begin the year, and will consist of a couple of editorial changes. Firstly, Patricia Durance will be stepping down as Co-Editor this year. I just wanted to take the opportunity to thank Patricia for her service to Applied Earth Science during her time as part of the editorial team and wish her luck in future ventures. I will also be stepping down as Editor of Applied Earth Science in January 2023. I have been involved with the journal since 2010, was Co-Editor from 2013 to 2019, and will have been Editor for nearly four years when I step down after taking over from Neil Phillips in 2019. My time with Applied Earth Science has been challenging but very rewarding, and has given me useful insights into scientific publishing and writing, editing, peer-reviewing, and a huge array of different types of scientific research. I’d like to thank the team at Taylor and Francis (and Maney before them) for their efforts on behalf of the journal, my Co-Editors and colleagues on the editorial board, and all of the authors and reviewers who have contributed to the journal over the past 12 years.","PeriodicalId":43298,"journal":{"name":"Applied Earth Science-Transactions of the Institutions of Mining and Metallurgy","volume":"131 1","pages":"1 - 1"},"PeriodicalIF":1.0,"publicationDate":"2022-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43044288","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}
Pub Date : 2022-01-02DOI: 10.1080/25726838.2022.2035640
Abate A. Melaku, Worash Getaneh, Balemual Atnafu
ABSTRACT The genesis of the Enkafela Mn deposit and associated processes were investigated using field mapping, mineralogical and geochemical analyses by XRD, ICP-MS/AES and XRF. The geology is constituted by limestone, evaporites/gypsum, conglomerates and basalt. The orebody is hosted in the limestone and has two distinctive manganese layers: a massive bottom and powdery top. Pyrolusite, romanechite and birnessite are the major ore minerals. The geochemical results indicate elevated MnO (av. 70.25 wt-%), Ba (>10,000 ppm), Sr (>10,000 ppm) and depleted Fe2O3 (av. 0.37 wt-%) and other metals. The massive orebody has higher (172.9 ppm) REE content than the powdery ore (7.84 ppm). Chondrite normalised REE plot shows LREE enrichment for both orebodies. The massive manganese layer shows enrichment in Ce and no Eu anomaly. The powdery manganese is depleted in Ce and Eu. The geochemical and mineralogical studies indicate that the manganese mineralisation has dual sources: hydrogenous and hydrothermal sources (for the massive orebody), and hydrothermal (for the powdery). The data suggest that there was active submarine hydrothermal activity in Dallol associated with the regional geodynamic events while the area was inundated by the Red Sea during the Pleistocene.
{"title":"Genesis of the Enkafela Mn deposit: a record of submarine hydrothermal activity in the Afar Depression, Northeast Ethiopia","authors":"Abate A. Melaku, Worash Getaneh, Balemual Atnafu","doi":"10.1080/25726838.2022.2035640","DOIUrl":"https://doi.org/10.1080/25726838.2022.2035640","url":null,"abstract":"ABSTRACT The genesis of the Enkafela Mn deposit and associated processes were investigated using field mapping, mineralogical and geochemical analyses by XRD, ICP-MS/AES and XRF. The geology is constituted by limestone, evaporites/gypsum, conglomerates and basalt. The orebody is hosted in the limestone and has two distinctive manganese layers: a massive bottom and powdery top. Pyrolusite, romanechite and birnessite are the major ore minerals. The geochemical results indicate elevated MnO (av. 70.25 wt-%), Ba (>10,000 ppm), Sr (>10,000 ppm) and depleted Fe2O3 (av. 0.37 wt-%) and other metals. The massive orebody has higher (172.9 ppm) REE content than the powdery ore (7.84 ppm). Chondrite normalised REE plot shows LREE enrichment for both orebodies. The massive manganese layer shows enrichment in Ce and no Eu anomaly. The powdery manganese is depleted in Ce and Eu. The geochemical and mineralogical studies indicate that the manganese mineralisation has dual sources: hydrogenous and hydrothermal sources (for the massive orebody), and hydrothermal (for the powdery). The data suggest that there was active submarine hydrothermal activity in Dallol associated with the regional geodynamic events while the area was inundated by the Red Sea during the Pleistocene.","PeriodicalId":43298,"journal":{"name":"Applied Earth Science-Transactions of the Institutions of Mining and Metallurgy","volume":"131 1","pages":"2 - 14"},"PeriodicalIF":1.0,"publicationDate":"2022-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48416997","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}
Pub Date : 2021-10-26DOI: 10.1080/25726838.2021.1992815
S. Mahmoudi, A. Bennour
ABSTRACT The mineralogical, chemical, physical and thermal analyses of the representative clays from North Africa (Algeria, Morocco and Tunisia) have been studied for their potential use in traditional ceramic industry. The clay fractions of the Moroccan and Algerian clays are essentially composed of illite (38 and 21%, respectively) and kaolinite (17 and 12%, respectively) as predominant minerals, with subordinate I/Sm mixed-layer (10 and 3%, respectively). The non-clay minerals are quartz, calcite, dolomite and occasionally plagioclase and haematite. Tunisian clays are composed of similar proportions of kaolinite (15%), smectite (15%), illite (12%) and palygorskite (9%), whereas their associated minerals are quartz (30%), calcite (15%) and rarely plagioclase (4%). The chemical data show agreement with estimated mineralogical compositions. All the samples contain large amounts of iron (>5.6%) and earth-alkaline oxides (>6.9%), and high values of LOI (>12%). Algerian clays show high plasticity (PI = 40%), requiring particular attention and careful temperature control during drying to avoid the deformation and the formation of cracks in the ceramic bodies, whereas the Tunisian and Moroccan clays (PI = 18% and 16%, respectively) show acceptable behaviour in shaping and drying. The average grain-size distribution demonstrates a substantial amount of the silt and clay fractions in raw materials which are therefore suitable for easy shaping of paste without any special need for further adjustments. Indeed, the amount of fraction upper 63 µm is lower less than 2%. The main transformations during firing are influenced by the abundance of components such as Fe2O3, CaO, MgO, K2O and Na2O and observed above 1000°C with the appearance of new crystalline phases, especially mullite, spinel, plagioclase, diopside and haematite. The technical parameters of fired pieces (firing shrinkage, water absorption and flexural strength) fall within the ceramic international standards (ISO).
{"title":"Characterisation and ceramic application of clays from North Africa","authors":"S. Mahmoudi, A. Bennour","doi":"10.1080/25726838.2021.1992815","DOIUrl":"https://doi.org/10.1080/25726838.2021.1992815","url":null,"abstract":"ABSTRACT The mineralogical, chemical, physical and thermal analyses of the representative clays from North Africa (Algeria, Morocco and Tunisia) have been studied for their potential use in traditional ceramic industry. The clay fractions of the Moroccan and Algerian clays are essentially composed of illite (38 and 21%, respectively) and kaolinite (17 and 12%, respectively) as predominant minerals, with subordinate I/Sm mixed-layer (10 and 3%, respectively). The non-clay minerals are quartz, calcite, dolomite and occasionally plagioclase and haematite. Tunisian clays are composed of similar proportions of kaolinite (15%), smectite (15%), illite (12%) and palygorskite (9%), whereas their associated minerals are quartz (30%), calcite (15%) and rarely plagioclase (4%). The chemical data show agreement with estimated mineralogical compositions. All the samples contain large amounts of iron (>5.6%) and earth-alkaline oxides (>6.9%), and high values of LOI (>12%). Algerian clays show high plasticity (PI = 40%), requiring particular attention and careful temperature control during drying to avoid the deformation and the formation of cracks in the ceramic bodies, whereas the Tunisian and Moroccan clays (PI = 18% and 16%, respectively) show acceptable behaviour in shaping and drying. The average grain-size distribution demonstrates a substantial amount of the silt and clay fractions in raw materials which are therefore suitable for easy shaping of paste without any special need for further adjustments. Indeed, the amount of fraction upper 63 µm is lower less than 2%. The main transformations during firing are influenced by the abundance of components such as Fe2O3, CaO, MgO, K2O and Na2O and observed above 1000°C with the appearance of new crystalline phases, especially mullite, spinel, plagioclase, diopside and haematite. The technical parameters of fired pieces (firing shrinkage, water absorption and flexural strength) fall within the ceramic international standards (ISO).","PeriodicalId":43298,"journal":{"name":"Applied Earth Science-Transactions of the Institutions of Mining and Metallurgy","volume":"131 1","pages":"15 - 26"},"PeriodicalIF":1.0,"publicationDate":"2021-10-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42263557","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}
Pub Date : 2021-10-02DOI: 10.1080/25726838.2022.2079856
S. Jowitt
Welcome to the second issue of Volume 131 of Applied Earth Science. This issue contains papers focused on a range of different aspects of mineral exploration, the distribution of metals within mineralizing systems, and the processes involved in the formation of mineral deposits. The first of these papers is by Mulja (2022) who focuses on stream sediment geochemical data for the central Aceh area of northern Sumatra, Indonesia, as part of efforts to generate mineral potential maps for this region for hydrothermal Cu–Au mineralisation. The paper by de Oliveira et al. (2022) focuses on the 3D distribution of Cu, Zn, and Pb within the Palmeirópolis volcanogenic massive sulphide (VMS) deposit, located in Tocantins state, central Brazil. This research links the distribution of metals within this VMS system with the distribution of hosting lithologies and deformation as well as the original mineralising processes, and compares this distribution with other VMS deposits globally. The paper by Raphalalani et al. (2022) focuses on industrial mineralogy, specifically the formation and potential uses of kaolin deposits of the Limpopo province of South Africa. These kaolins formed in a supergene environment and this research determined that they are suitable for use in the manufacturing of thin-walled hollow bricks. The final paper in this issue is by Phelps-Barber et al. (2022), who outline recent pegmatite-hosted spodumene lithium mineralisation in Western Australia. These discoveries have a number of similarities that provide useful exploration criteria as well as outlining the potential for further Archaean pegmatite-hosted lithium discoveries in this region. I’d also just like to highlight current and upcoming editorial opportunities with Applied Earth Science. As I mentioned in my previous editorial we are actively in the process of filling a co-Editor position within the journal and are still accepting applications for this role. More details on the Editor position within Applied Earth Science will be made available later in 2022 – watch this space for more and see you in issue three.
{"title":"Editorial","authors":"S. Jowitt","doi":"10.1080/25726838.2022.2079856","DOIUrl":"https://doi.org/10.1080/25726838.2022.2079856","url":null,"abstract":"Welcome to the second issue of Volume 131 of Applied Earth Science. This issue contains papers focused on a range of different aspects of mineral exploration, the distribution of metals within mineralizing systems, and the processes involved in the formation of mineral deposits. The first of these papers is by Mulja (2022) who focuses on stream sediment geochemical data for the central Aceh area of northern Sumatra, Indonesia, as part of efforts to generate mineral potential maps for this region for hydrothermal Cu–Au mineralisation. The paper by de Oliveira et al. (2022) focuses on the 3D distribution of Cu, Zn, and Pb within the Palmeirópolis volcanogenic massive sulphide (VMS) deposit, located in Tocantins state, central Brazil. This research links the distribution of metals within this VMS system with the distribution of hosting lithologies and deformation as well as the original mineralising processes, and compares this distribution with other VMS deposits globally. The paper by Raphalalani et al. (2022) focuses on industrial mineralogy, specifically the formation and potential uses of kaolin deposits of the Limpopo province of South Africa. These kaolins formed in a supergene environment and this research determined that they are suitable for use in the manufacturing of thin-walled hollow bricks. The final paper in this issue is by Phelps-Barber et al. (2022), who outline recent pegmatite-hosted spodumene lithium mineralisation in Western Australia. These discoveries have a number of similarities that provide useful exploration criteria as well as outlining the potential for further Archaean pegmatite-hosted lithium discoveries in this region. I’d also just like to highlight current and upcoming editorial opportunities with Applied Earth Science. As I mentioned in my previous editorial we are actively in the process of filling a co-Editor position within the journal and are still accepting applications for this role. More details on the Editor position within Applied Earth Science will be made available later in 2022 – watch this space for more and see you in issue three.","PeriodicalId":43298,"journal":{"name":"Applied Earth Science-Transactions of the Institutions of Mining and Metallurgy","volume":"131 1","pages":"49 - 49"},"PeriodicalIF":1.0,"publicationDate":"2021-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45447637","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}
Pub Date : 2021-09-23DOI: 10.1080/25726838.2021.1975249
L. Nerovich, T. Kaulina, E. Kunakkuzin, M. Gannibal
ABSTRACT The Vulvara anorthosites occur among the rocks of intermediate composition, in contrast to most Lapland granulite belt (LGB) anorthosites, associated with mafic granulites. The U-Pb, Sm-Nd and REE geochemical data were used to compare Vulvara with other LGB anorthosites. The intrusion of the Vulvara massif occurred in the interval of 2100–1965 Ma. The first metamorphic processing took place 1947 ± 11 Ma ago under granulite facies. Postgranulite transformations occurred 1900–1850 Ma ago under amphibolite facies; earlier (1896 ± 15 Ma) and later (1852 ± 17 Ma, 1846 ± 16 Ma) thermal events were established. The Vulvara anorthosites, in comparison with other LGB anorthosites, are distinguished by a more acidic composition of plagioclase, a higher F number of rocks and mafic minerals, a higher content of SiO2, Na2O, K2O, Ba, Sr, Zr, Nb, Rb, and a lower content of CaO. The Sm-Nd and REE geochemistry suggest that there are three groups of LGB anorthosites, distinguished both by age and magma source.
{"title":"Geochemical systematics and U–Pb zircon age of the Vulvara anorthosite massif, Lapland granulite belt, Baltic shield: magmatic sources and metamorphic alteration of the rocks","authors":"L. Nerovich, T. Kaulina, E. Kunakkuzin, M. Gannibal","doi":"10.1080/25726838.2021.1975249","DOIUrl":"https://doi.org/10.1080/25726838.2021.1975249","url":null,"abstract":"ABSTRACT The Vulvara anorthosites occur among the rocks of intermediate composition, in contrast to most Lapland granulite belt (LGB) anorthosites, associated with mafic granulites. The U-Pb, Sm-Nd and REE geochemical data were used to compare Vulvara with other LGB anorthosites. The intrusion of the Vulvara massif occurred in the interval of 2100–1965 Ma. The first metamorphic processing took place 1947 ± 11 Ma ago under granulite facies. Postgranulite transformations occurred 1900–1850 Ma ago under amphibolite facies; earlier (1896 ± 15 Ma) and later (1852 ± 17 Ma, 1846 ± 16 Ma) thermal events were established. The Vulvara anorthosites, in comparison with other LGB anorthosites, are distinguished by a more acidic composition of plagioclase, a higher F number of rocks and mafic minerals, a higher content of SiO2, Na2O, K2O, Ba, Sr, Zr, Nb, Rb, and a lower content of CaO. The Sm-Nd and REE geochemistry suggest that there are three groups of LGB anorthosites, distinguished both by age and magma source.","PeriodicalId":43298,"journal":{"name":"Applied Earth Science-Transactions of the Institutions of Mining and Metallurgy","volume":"130 1","pages":"222 - 240"},"PeriodicalIF":1.0,"publicationDate":"2021-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42257014","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}
Pub Date : 2021-08-04DOI: 10.1080/25726838.2021.1959863
V. Miguel-Silva, B. Afonseca, J. Costa, A. H. S. Medeiros
ABSTRACT Kriging relies on the assumption that the study area is within an infinite domain. In practice, Kriging is performed in a finite domain, generally defined by geology, and a string of samples along a drillhole is commonly truncated inside this domain. In the Kriging system, the string-end samples receive more weight as they are less screened. This feature is referred to as the ‘String Effect’ and becomes a concern in non-stationary domains in which the end and central samples are systematically different, such as (i) domains with grade enrichment or diminution towards the centre, or (ii) end samples are partially contaminated with material from adjacent domains due to sampling methods. Three methods available in the literature and one novel approach (Kriging with Adjusted Declustering [KAD]) are applied to continuous and categorical variables in three case studies. The KAD results in a significant improvement in the results of all case study models.
克里金的假设是研究区域在无限域中。在实践中，克里格是在一个有限的域中进行的，通常由地质学定义，沿着钻孔的一串样本通常在这个域中被截断。在克里格系统中，弦端样品受到更多的重量，因为他们较少筛选。这种特征被称为“弦效应”，在末端和中心样品系统不同的非平稳域中成为一个问题，例如(i)区域向中心富集或减少，或(ii)由于采样方法，末端样品部分被邻近区域的物质污染。在三个案例研究中，文献中有三种可用的方法和一种新颖的方法(Kriging with Adjusted clustering [KAD])应用于连续变量和分类变量。KAD显著改善了所有案例研究模型的结果。
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