In this study, we present summary statistics for multi-element soil geochemistry across Western Australia based on over 74,000 soil samples using the UltraFine+ ® method that extracts and analyses the clay (<2 µm) fraction of a soil sample. This method is a critical advancement for the detection of mobile element signatures for soil geochemical mineral exploration surveys in cover. However, existing estimates of background metal abundances acquired with other methods and on different sample media do not readily provide context for these analyses as recovery from the fine fraction differs to that of whole-sample analysis. We therefore present herein the geochemical results for 52 elements including precious, base and critical metals, as well as commonly associated pathfinder elements for Western Australian samples analysed during several research projects by the Commonwealth Scientific and Industrial Research Organisation. This dataset is separated by tectonic unit, into the Eastern Goldfields Superterrane and the Youanmi Terrane in the Yilgarn Craton, the Pilbara Craton and Sylvania Inlier, the Gascoyne, Lamboo and Aileron Provinces, and the Bryah and Earaheedy Basins to provide exploration-relevant context in these areas. We discuss some of the general trends observed for twelve of these elements, as well as some considerations for the use of these data in comparison to other geochemical soil surveys and with regards to mineral exploration settings. The samples presented in this study are not evenly distributed across Western Australia and limited information is available to correlate whether lithology at depth is mineralised or barren. However, in the absence of other, systematic datasets using the <2 µm size fraction, these data present a suitable first-pass resource of element abundance ranges in areas of mineral exploration interest using the UltraFine+ ® method in some of the mineral endowed areas of Western Australia. Supplementary material: https://doi.org/10.6084/m9.figshare.c.6919933
{"title":"Multi-element geochemical analyses on ultrafine soils in Western Australia - Towards establishing abundance ranges in mineral exploration settings","authors":"Anicia Henne, Ryan R.R.P Noble, Morgan Williams","doi":"10.1144/geochem2023-043","DOIUrl":"https://doi.org/10.1144/geochem2023-043","url":null,"abstract":"In this study, we present summary statistics for multi-element soil geochemistry across Western Australia based on over 74,000 soil samples using the UltraFine+ ® method that extracts and analyses the clay (<2 µm) fraction of a soil sample. This method is a critical advancement for the detection of mobile element signatures for soil geochemical mineral exploration surveys in cover. However, existing estimates of background metal abundances acquired with other methods and on different sample media do not readily provide context for these analyses as recovery from the fine fraction differs to that of whole-sample analysis. We therefore present herein the geochemical results for 52 elements including precious, base and critical metals, as well as commonly associated pathfinder elements for Western Australian samples analysed during several research projects by the Commonwealth Scientific and Industrial Research Organisation. This dataset is separated by tectonic unit, into the Eastern Goldfields Superterrane and the Youanmi Terrane in the Yilgarn Craton, the Pilbara Craton and Sylvania Inlier, the Gascoyne, Lamboo and Aileron Provinces, and the Bryah and Earaheedy Basins to provide exploration-relevant context in these areas. We discuss some of the general trends observed for twelve of these elements, as well as some considerations for the use of these data in comparison to other geochemical soil surveys and with regards to mineral exploration settings. The samples presented in this study are not evenly distributed across Western Australia and limited information is available to correlate whether lithology at depth is mineralised or barren. However, in the absence of other, systematic datasets using the <2 µm size fraction, these data present a suitable first-pass resource of element abundance ranges in areas of mineral exploration interest using the UltraFine+ ® method in some of the mineral endowed areas of Western Australia. Supplementary material: https://doi.org/10.6084/m9.figshare.c.6919933","PeriodicalId":55114,"journal":{"name":"Geochemistry-Exploration Environment Analysis","volume":"14 23","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134953720","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
McLean Trott, Cole Mooney, Shervin Azad, Sam Sattarzadeh, Britt Bluemel, Matthew Leybourne, Daniel Layton-Matthews
Integration of multiple data types is beneficial for prediction of geological characteristics. From the perspective that geochemistry characterizes the composition of a rock mass, hyperspectral data characterizes alteration mineralogy, and image feature extraction characterizes texture, most geological classifications would be well-informed by the combination of these three features. The process of meaningfully integrating distinctly sourced datasets and producing scale-relevant predictions for geological classifications involves several steps. We demonstrate a workflow to comprehensively structure and integrate these three feature families, refine training data, predict alteration classes, and mitigate noise derived from scale mismatch in output predictions. The dataset, compiled from the Josemaria porphyry copper deposit in Argentina, is comprised of more than 14,000 intervals of approximately 2 m, taken from 36 drillholes, where geochemistry was merged with hyperspectral mineralogy represented as tabular pixel abundances, and textural metrics extracted from core imagery, structured into the geochemical interval. Feature engineering and principal component analysis provided insights into the behavior of the ore system during intermediate steps, as well as providing uncorrelated feature inputs for a random forest predictor. Training data were refined by producing an initial prediction, thresholding the predictions to >70% dominant class probability and using those (high probability) samples to produce a final model encoding better constrained separation between alteration assemblages. Prediction using the final model returned an accuracy of 82.5 %, as a function of model discrepancy combined with logging ambiguity and a scale mismatch between generalized logged intervals and much more granular (2 m) feature inputs. Noise reduction and generalization to desired resolution of output was achieved by applying the multiscale multivariate continuous wavelet transform tessellation method to class membership probabilities. Ultimately a large database of logged drill-core was homogenized using empirical methodologies. The described workflow is adaptable to distinct scenarios with some modification and is apt for integrating multiple input feature types and using them to systematically define geological classifications in drill-hole data.
{"title":"Alteration assemblage characterization using machine learning applied to high resolution drill-core images, hyperspectral data, and geochemistry","authors":"McLean Trott, Cole Mooney, Shervin Azad, Sam Sattarzadeh, Britt Bluemel, Matthew Leybourne, Daniel Layton-Matthews","doi":"10.1144/geochem2023-032","DOIUrl":"https://doi.org/10.1144/geochem2023-032","url":null,"abstract":"Integration of multiple data types is beneficial for prediction of geological characteristics. From the perspective that geochemistry characterizes the composition of a rock mass, hyperspectral data characterizes alteration mineralogy, and image feature extraction characterizes texture, most geological classifications would be well-informed by the combination of these three features. The process of meaningfully integrating distinctly sourced datasets and producing scale-relevant predictions for geological classifications involves several steps. We demonstrate a workflow to comprehensively structure and integrate these three feature families, refine training data, predict alteration classes, and mitigate noise derived from scale mismatch in output predictions. The dataset, compiled from the Josemaria porphyry copper deposit in Argentina, is comprised of more than 14,000 intervals of approximately 2 m, taken from 36 drillholes, where geochemistry was merged with hyperspectral mineralogy represented as tabular pixel abundances, and textural metrics extracted from core imagery, structured into the geochemical interval. Feature engineering and principal component analysis provided insights into the behavior of the ore system during intermediate steps, as well as providing uncorrelated feature inputs for a random forest predictor. Training data were refined by producing an initial prediction, thresholding the predictions to >70% dominant class probability and using those (high probability) samples to produce a final model encoding better constrained separation between alteration assemblages. Prediction using the final model returned an accuracy of 82.5 %, as a function of model discrepancy combined with logging ambiguity and a scale mismatch between generalized logged intervals and much more granular (2 m) feature inputs. Noise reduction and generalization to desired resolution of output was achieved by applying the multiscale multivariate continuous wavelet transform tessellation method to class membership probabilities. Ultimately a large database of logged drill-core was homogenized using empirical methodologies. The described workflow is adaptable to distinct scenarios with some modification and is apt for integrating multiple input feature types and using them to systematically define geological classifications in drill-hole data.","PeriodicalId":55114,"journal":{"name":"Geochemistry-Exploration Environment Analysis","volume":"174 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135341938","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The Nowa Sól deposit is a part of the newly discovered Northern Copper Belt and is situated some 30 km north-west of the Lubin-Sieroszowice Mining District (so called New Copper District) in SW Poland. The ore horizon spans across the upper part of the Lower Permian (Rotliegend) terrestrial redbeds and the lower part of the Upper Permian (Zechstein) marine rocks and comprises three lithotypes: sandstone, shale and carbonate. The high-grade shale ore has polymetallic characteristics and is a crucial host for by-product metals such as silver, cobalt, and nickel (studied in this paper), but also molybdenum, vanadium, and rhenium. The results of bulk-rock and electron microprobe as well as mineralogical (optical and scanning electron microscope) data of the mineralized, organic-rich shale ore from the Nowa Sól deposit are presented. This thin stratigraphic horizon, ranging from 0.06 m to 0.59 m, shows notable concentrations of critical metals, including on average 15.9 wt. % copper, 715 g/t silver, 318 g/t cobalt, and 345 g/t nickel. It constitutes less than 10% of the total ore mass, but accounts for 36% of the silver, 40% of the nickel, and 42% of the cobalt found within the deposit. The ore sulfides in the mineralized shale in the Nowa Sól deposit include chalcocite, djurleite, bornite, accompanied by digenite, covellite, tennantite, galena, sphalerite, and pyrite. The silver content within the copper sulfides exhibits a linear decrease: chalcocite > djurleite > bornite. Three primary silver minerals are identified within the shale ore, namely native silver, silver amalgam, and stromeyerite. Two types of silver amalgam are observed: Hg-rich and Hg-poor. Cobaltite and gersdorffite represent the primary cobalt and nickel minerals, occurring as micrometer-sized inclusions within chalcocite and djurleite. Textural observations suggest that the silver, cobalt, and nickel mineralization postdates the major phase of copper sulfide precipitation. It is shown that in the Nowa Sól deposit, the Kupferschiefer horizon has acted as a geochemical barrier for abovementioned metals during protracted time – from early, syndepositional to late, epigenetic stage of basin evolution. Supplementary material: https://doi.org/10.6084/m9.figshare.c.6873631
Nowa Sól矿床是新发现的北铜带的一部分，位于波兰西南部Lubin-Sieroszowice矿区(所谓的新铜矿区)西北约30公里处。矿层横跨下二叠统(Rotliegend)陆相红层上部和上二叠统(Zechstein)海相岩下部，包括砂岩、页岩和碳酸盐岩三种岩型。高品位页岩矿具有多金属特征，是副产物金属如银、钴、镍(本文研究)以及钼、钒、铼的重要宿主。本文介绍了Nowa Sól矿床富有机质矿化页岩矿石的体岩、电子探针和矿物学(光学和扫描电镜)资料。这个薄的地层层位，范围从0.06米到0.59米，显示出显著的关键金属浓度，包括平均15.9 wt. %的铜，715 g/t的银，318 g/t的钴和345 g/t的镍。它占总矿石质量的不到10%，但占矿床中发现的银的36%，镍的40%和钴的42%。Nowa Sól矿床矿化页岩中矿石硫化物主要有辉铜矿、闪铜矿、斑铜矿，伴生有银长铜矿、银长石、天长石、方铅矿、闪锌矿和黄铁矿。铜硫化物中银的含量呈线性下降趋势:辉铜矿;djurleite祝辞斑铜矿。在页岩矿石中鉴定出三种原生银矿物，即天然银、银汞合金和闪辉石。观察到两种类型的银汞合金:富汞和贫汞。钴矿和辉闪石是主要的钴和镍矿物，以微米大小的包裹体存在于辉铜矿和辉闪岩中。结构观测表明，银、钴和镍矿化发生在硫化铜沉淀的主要阶段之后。结果表明，在Nowa Sól矿床中，从盆地演化早期同沉积到晚期的表成阶段，Kupferschiefer层位在较长时间内对上述金属起着地球化学屏障的作用。补充资料:https://doi.org/10.6084/m9.figshare.c.6873631
{"title":"Silver, cobalt and nickel mineralogy and geochemistry of shale ore in the sediment-hosted stratiform Nowa Sól Cu-Ag deposit, SW Poland","authors":"T. Bieńko, J. Wierchowiec, A. Pietrzela","doi":"10.1144/geochem2023-035","DOIUrl":"https://doi.org/10.1144/geochem2023-035","url":null,"abstract":"The Nowa Sól deposit is a part of the newly discovered Northern Copper Belt and is situated some 30 km north-west of the Lubin-Sieroszowice Mining District (so called New Copper District) in SW Poland. The ore horizon spans across the upper part of the Lower Permian (Rotliegend) terrestrial redbeds and the lower part of the Upper Permian (Zechstein) marine rocks and comprises three lithotypes: sandstone, shale and carbonate. The high-grade shale ore has polymetallic characteristics and is a crucial host for by-product metals such as silver, cobalt, and nickel (studied in this paper), but also molybdenum, vanadium, and rhenium. The results of bulk-rock and electron microprobe as well as mineralogical (optical and scanning electron microscope) data of the mineralized, organic-rich shale ore from the Nowa Sól deposit are presented. This thin stratigraphic horizon, ranging from 0.06 m to 0.59 m, shows notable concentrations of critical metals, including on average 15.9 wt. % copper, 715 g/t silver, 318 g/t cobalt, and 345 g/t nickel. It constitutes less than 10% of the total ore mass, but accounts for 36% of the silver, 40% of the nickel, and 42% of the cobalt found within the deposit. The ore sulfides in the mineralized shale in the Nowa Sól deposit include chalcocite, djurleite, bornite, accompanied by digenite, covellite, tennantite, galena, sphalerite, and pyrite. The silver content within the copper sulfides exhibits a linear decrease: chalcocite > djurleite > bornite. Three primary silver minerals are identified within the shale ore, namely native silver, silver amalgam, and stromeyerite. Two types of silver amalgam are observed: Hg-rich and Hg-poor. Cobaltite and gersdorffite represent the primary cobalt and nickel minerals, occurring as micrometer-sized inclusions within chalcocite and djurleite. Textural observations suggest that the silver, cobalt, and nickel mineralization postdates the major phase of copper sulfide precipitation. It is shown that in the Nowa Sól deposit, the Kupferschiefer horizon has acted as a geochemical barrier for abovementioned metals during protracted time – from early, syndepositional to late, epigenetic stage of basin evolution. Supplementary material: https://doi.org/10.6084/m9.figshare.c.6873631","PeriodicalId":55114,"journal":{"name":"Geochemistry-Exploration Environment Analysis","volume":"37 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136013408","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Patrice de Caritat, Eric C. Grunsky, David B. Smith
A novel method of estimating the silica (SiO 2 ) and loss-on-ignition (LOI) concentrations for the North American Soil Geochemical Landscapes (NASGL) project datasets is proposed. Combining the precision of the geochemical determinations with the completeness of the mineralogical NASGL data, we suggest a ‘reverse normative’ or inversion approach to first calculate the minimum SiO 2 , water (H 2 O) and carbon dioxide (CO 2 ) concentrations in weight percent (wt%) in these samples. These can be used in a first step to compute minimum and maximum estimates for SiO 2 . In a recursive step, a ‘consensus’ SiO 2 is then established as the average between the two aforementioned SiO 2 estimates, trimmed as necessary to yield a total composition (major oxides converted from reported Al, Ca, Fe, K, Mg, Mn, Na, P, S and Ti elemental concentrations + ‘consensus’ SiO 2 + reported trace element concentrations converted to wt% + ‘normative’ H 2 O + ‘normative’ CO 2 ) of no more than 100 wt%. Any remaining compositional gap between 100 wt% and this sum is considered ‘other’ LOI and likely includes H 2 O and CO 2 from the reported ‘amorphous’ phase (of unknown geochemical or mineralogical composition) as well as other volatile components present in soil. We validate the technique against a separate dataset from Australia where geochemical (including all major oxides) and mineralogical data exist on the same samples. The correlation between predicted and observed SiO 2 is linear, strong ( R 2 = 0.91) and homoscedastic. We also compare the estimated NASGL SiO 2 concentrations with a sparser, publicly available continental-scale survey over the conterminous USA, the ‘Shacklette and Boerngen’ dataset. This comparison shows the new data to be a reasonable representation of SiO 2 values measured on the ground over the conterminous USA. We recommend the approach of combining geochemical and mineralogical information to estimate missing SiO 2 and LOI by the recursive inversion approach in datasets elsewhere, with the caveat to always validate results.
{"title":"Estimating the silica content and loss-on-ignition in the North American Soil Geochemical Landscapes datasets: a recursive inversion approach","authors":"Patrice de Caritat, Eric C. Grunsky, David B. Smith","doi":"10.1144/geochem2023-039","DOIUrl":"https://doi.org/10.1144/geochem2023-039","url":null,"abstract":"A novel method of estimating the silica (SiO 2 ) and loss-on-ignition (LOI) concentrations for the North American Soil Geochemical Landscapes (NASGL) project datasets is proposed. Combining the precision of the geochemical determinations with the completeness of the mineralogical NASGL data, we suggest a ‘reverse normative’ or inversion approach to first calculate the minimum SiO 2 , water (H 2 O) and carbon dioxide (CO 2 ) concentrations in weight percent (wt%) in these samples. These can be used in a first step to compute minimum and maximum estimates for SiO 2 . In a recursive step, a ‘consensus’ SiO 2 is then established as the average between the two aforementioned SiO 2 estimates, trimmed as necessary to yield a total composition (major oxides converted from reported Al, Ca, Fe, K, Mg, Mn, Na, P, S and Ti elemental concentrations + ‘consensus’ SiO 2 + reported trace element concentrations converted to wt% + ‘normative’ H 2 O + ‘normative’ CO 2 ) of no more than 100 wt%. Any remaining compositional gap between 100 wt% and this sum is considered ‘other’ LOI and likely includes H 2 O and CO 2 from the reported ‘amorphous’ phase (of unknown geochemical or mineralogical composition) as well as other volatile components present in soil. We validate the technique against a separate dataset from Australia where geochemical (including all major oxides) and mineralogical data exist on the same samples. The correlation between predicted and observed SiO 2 is linear, strong ( R 2 = 0.91) and homoscedastic. We also compare the estimated NASGL SiO 2 concentrations with a sparser, publicly available continental-scale survey over the conterminous USA, the ‘Shacklette and Boerngen’ dataset. This comparison shows the new data to be a reasonable representation of SiO 2 values measured on the ground over the conterminous USA. We recommend the approach of combining geochemical and mineralogical information to estimate missing SiO 2 and LOI by the recursive inversion approach in datasets elsewhere, with the caveat to always validate results.","PeriodicalId":55114,"journal":{"name":"Geochemistry-Exploration Environment Analysis","volume":"23 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-08-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134932483","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
M. McClenaghan, R. Paulen, I. Smith, J. Rice, A. Plouffe, I. McMartin, J. Campbell, M. Lehtonen, M. Parsasadr, C. Beckett-Brown
Since the 1970s, till geochemical and indicator mineral methods for mineral exploration, provenance studies and environmental research in glaciated terrain have been developed, tested, and refined. This paper summarizes these methods, focussing on field and laboratory methods for till geochemical, indicator mineral, and boulder surveys. This review of protocols is meant to be a guide for the mineral exploration industry and publicly funded agencies. The paper summarizes till as a sample medium, describes the formation of glacial dispersal trains, and methods for till sample collection, sample processing, matrix geochemistry, indicator mineral analyses, quality assurance/quality control (QA/QC) procedures, and data reporting and interpretation. The methods described here can be used to conduct reconnaissance- to deposit-scale till sampling surveys to assess mineral resource potential and establish environmental baselines. Thematic collection: This article is part of the Reviews in Exploration Geochemistry collection available at: https://www.lyellcollection.org/topic/collections/reviews-in-exploration-geochemistry Supplementary material: https://doi.org/10.6084/m9.figshare.c.6786087
{"title":"Review of till geochemistry and indicator mineral methods for mineral exploration in glaciated terrain","authors":"M. McClenaghan, R. Paulen, I. Smith, J. Rice, A. Plouffe, I. McMartin, J. Campbell, M. Lehtonen, M. Parsasadr, C. Beckett-Brown","doi":"10.1144/geochem2023-013","DOIUrl":"https://doi.org/10.1144/geochem2023-013","url":null,"abstract":"Since the 1970s, till geochemical and indicator mineral methods for mineral exploration, provenance studies and environmental research in glaciated terrain have been developed, tested, and refined. This paper summarizes these methods, focussing on field and laboratory methods for till geochemical, indicator mineral, and boulder surveys. This review of protocols is meant to be a guide for the mineral exploration industry and publicly funded agencies. The paper summarizes till as a sample medium, describes the formation of glacial dispersal trains, and methods for till sample collection, sample processing, matrix geochemistry, indicator mineral analyses, quality assurance/quality control (QA/QC) procedures, and data reporting and interpretation. The methods described here can be used to conduct reconnaissance- to deposit-scale till sampling surveys to assess mineral resource potential and establish environmental baselines.\u0000 \u0000 Thematic collection:\u0000 This article is part of the Reviews in Exploration Geochemistry collection available at:\u0000 https://www.lyellcollection.org/topic/collections/reviews-in-exploration-geochemistry\u0000 \u0000 \u0000 Supplementary material:\u0000 https://doi.org/10.6084/m9.figshare.c.6786087\u0000","PeriodicalId":55114,"journal":{"name":"Geochemistry-Exploration Environment Analysis","volume":" ","pages":""},"PeriodicalIF":2.4,"publicationDate":"2023-08-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45164936","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Yuqing Zhao, G. Han, Rui Qu, Dong Yang, Q. Dong, Chao Song
The central section of China's South-to-North Water Diversion Project (SNWD) has been designated as a national water conservation area, and the soil ecological security in its associated watersheds is of great importance. A total of 204 soil samples (0-20 cm) were obtained from the Laoguanhe River Basin. The concentrations of seven elements (Cd, Cr, Cu, Ni, Zn, Pb and Hg) were determined by ICP-MS and AFS following a near-total acid dissolution. Data analyses (including potential ecological risk, principal component analysis, geostatistical analysis and positive matrix factorization model) were applied to evaluate the contamination of soil heavy metals and to identify their sources. The research results demonstrated that the mean contents of these seven elements exceeded background values for Henan Province, China, indicating human disturbance. Ecological risk evaluation revealed that Cd was the most frequently detected and highly polluted heavy metal., Principal component analysis indicated that Cr, Ni and Cu stem from natural sources, while Zn and Cd are predominantly influenced by agricultural activities. Additionally, industrial activities and atmospheric deposition were responsible for the excess presence of Pb and Hg. The study suggests taking measures to control Cd sources in agricultural areas, reducing heavy metals input to the river, and providing scientific support for managing water quality.
{"title":"Spatial distribution, ecological risk and origin of soil heavy metals in Laoguanhe watershed of the Middle Route of China's South-to-North Water Diversion Project","authors":"Yuqing Zhao, G. Han, Rui Qu, Dong Yang, Q. Dong, Chao Song","doi":"10.1144/geochem2023-029","DOIUrl":"https://doi.org/10.1144/geochem2023-029","url":null,"abstract":"The central section of China's South-to-North Water Diversion Project (SNWD) has been designated as a national water conservation area, and the soil ecological security in its associated watersheds is of great importance. A total of 204 soil samples (0-20 cm) were obtained from the Laoguanhe River Basin. The concentrations of seven elements (Cd, Cr, Cu, Ni, Zn, Pb and Hg) were determined by ICP-MS and AFS following a near-total acid dissolution. Data analyses (including potential ecological risk, principal component analysis, geostatistical analysis and positive matrix factorization model) were applied to evaluate the contamination of soil heavy metals and to identify their sources. The research results demonstrated that the mean contents of these seven elements exceeded background values for Henan Province, China, indicating human disturbance. Ecological risk evaluation revealed that Cd was the most frequently detected and highly polluted heavy metal., Principal component analysis indicated that Cr, Ni and Cu stem from natural sources, while Zn and Cd are predominantly influenced by agricultural activities. Additionally, industrial activities and atmospheric deposition were responsible for the excess presence of Pb and Hg. The study suggests taking measures to control Cd sources in agricultural areas, reducing heavy metals input to the river, and providing scientific support for managing water quality.","PeriodicalId":55114,"journal":{"name":"Geochemistry-Exploration Environment Analysis","volume":" ","pages":""},"PeriodicalIF":2.4,"publicationDate":"2023-08-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45042697","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
We applied the Backward Elimination (BE) method as a criterion-based iterative stepwise method to estimate the concentration of Au from the variables Ag, Cu, Pb, and Zn. We optimized the quadratic polynomial model (QPM) on various boreholes and trenches. The results indicate that the vertical zonation of Au is associated with Ag and Cu, along with their respective elemental functions Ag×Cu, Pb 2 , Pb×Zn, and Zn 2 . On the other hand, the lateral dispersion of Au is determined by Pb and Zn, along with the essential functions Ag×Zn and Pb×Zn. Zonation is in-depth and is indicated primarily by Zn rather than Cu and minor Pb, with Cu-Pb-Zn gradually extending upward at the upper levels. The vertical zonation trend describes the Ag
{"title":"Geochemical dispersion evaluation by criterion-based backward elimination at the Glojeh polymetallic Au (Ag-Cu-Pb-Zn) vein deposit, NW Iran","authors":"F. Darabi-Golestan","doi":"10.1144/geochem2023-011","DOIUrl":"https://doi.org/10.1144/geochem2023-011","url":null,"abstract":"\u0000 We applied the Backward Elimination (BE) method as a criterion-based iterative stepwise method to estimate the concentration of Au from the variables Ag, Cu, Pb, and Zn. We optimized the quadratic polynomial model (QPM) on various boreholes and trenches. The results indicate that the vertical zonation of Au is associated with Ag and Cu, along with their respective elemental functions Ag×Cu, Pb\u0000 2\u0000 , Pb×Zn, and Zn\u0000 2\u0000 . On the other hand, the lateral dispersion of Au is determined by Pb and Zn, along with the essential functions Ag×Zn and Pb×Zn. Zonation is in-depth and is indicated primarily by Zn rather than Cu and minor Pb, with Cu-Pb-Zn gradually extending upward at the upper levels. The vertical zonation trend describes the Ag<Au<Cu<Pb<Zn sequence from proximal to distal veins, with the near-surface zone exhibiting enrichment in Zn. At the Glojeh site, the host rock value, Ag×Cu, Zn\u0000 2\u0000 , and Pb×Zn, were identified as strong indicators of the vertical occurrence of Au in the upper host rock, whereas Pb\u0000 2\u0000 proved more suitable for the deeper boreholes. Cu→Pb→Zn demonstrates the enrichment trend from depth to the surface. The lateral kriging surface estimation confirms the dispersion pattern of elements revealed in-depth at Glojeh. Our aims with this approach were to reduce the cost of fire-assay analysis due to high precision estimation by associated variables and determine elemental interactions and the lateral or vertical dependencies of elements.\u0000","PeriodicalId":55114,"journal":{"name":"Geochemistry-Exploration Environment Analysis","volume":" ","pages":""},"PeriodicalIF":2.4,"publicationDate":"2023-08-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43509361","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The Lower Devonian plant-bearing Rhynie Chert, Aberdeenshire, UK, consists of sinters deposited by a hot spring system. Like many modern hot springs, the Rhynie geothermal system was lithium-rich, and its silica deposits are richer in lithium than other current or fossil sinters. Twenty samples of Rhynie sinter have a mean content of 255 ppm lithium. The high values imply exceptional lithium contents in the spring waters. Together with pegmatites and granites in the same region, the chert is related to a lithium-rich Late Caledonian magmatic suite, of which it is a surface expression. The measurements suggest that ancient hot spring deposits could provide valuable data during the exploration for lithium. Supplementary material: https://doi.org/10.6084/m9.figshare.c.6756506
{"title":"Surface expression of Late Caledonian magmatic lithium concentration, in the Rhynie Chert, UK","authors":"J. Parnell, J. Armstrong","doi":"10.1144/geochem2023-028","DOIUrl":"https://doi.org/10.1144/geochem2023-028","url":null,"abstract":"The Lower Devonian plant-bearing Rhynie Chert, Aberdeenshire, UK, consists of sinters deposited by a hot spring system. Like many modern hot springs, the Rhynie geothermal system was lithium-rich, and its silica deposits are richer in lithium than other current or fossil sinters. Twenty samples of Rhynie sinter have a mean content of 255 ppm lithium. The high values imply exceptional lithium contents in the spring waters. Together with pegmatites and granites in the same region, the chert is related to a lithium-rich Late Caledonian magmatic suite, of which it is a surface expression. The measurements suggest that ancient hot spring deposits could provide valuable data during the exploration for lithium.\u0000 \u0000 Supplementary material:\u0000 https://doi.org/10.6084/m9.figshare.c.6756506\u0000","PeriodicalId":55114,"journal":{"name":"Geochemistry-Exploration Environment Analysis","volume":" ","pages":""},"PeriodicalIF":2.4,"publicationDate":"2023-07-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43782930","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Breccia pipe deposits of the Grand Canyon region contain ore grade copper and uranium. Horn Creek is located near the Orphan Mine mineralized breccia pipe deposit and groundwater emerging from the bedrock in the headwaters of Horn Creek has the highest uranium concentrations in the region. Uranium decreases an order of magnitude between the groundwater at the top of the watershed and the groundwater emerging from the alluvial material lower in the watershed. Horn Creek water has low sulfur and uranium isotopic ratios which may suggest interaction with sulfide and uranium minerals found in mineralized breccia pipe deposits. Per- and polyfluoroalkyl substances (PFBA and PFBS) were found in low concentrations in groundwater from the bedrock and may be related to mining process materials or other anthropogenic activities. PHREEQC modeling suggests that water that is elevated in uranium emerging from the bedrock in the upper watershed may mix with other groundwater and atmospheric precipitation infiltrated into the alluvial material in the lower watershed. Tritium is elevated in Horn Creek groundwaters suggesting a component of modern water, some of which may have interacted with Orphan Mine workings. Additional studies could build on this understanding of chemistry changes in waters of Horn Creek to provide more direct evidence of contribution of water moving through the Orphan Mine. Thematic collection: This article is part of the Geochemical processes related to mined, milled, or natural metal deposits collection available at: https://www.lyellcollection.org/topic/collections/geochemical-processes-related-to-mined-milled-or-natural-metal-deposits Supplementary material: https://doi.org/10.6084/m9.figshare.c.6747638
{"title":"Anthropogenic influence on groundwater geochemistry in Horn Creek Watershed near the Orphan Mine in Grand Canyon National Park, Arizona, USA","authors":"Kimberly R. Beisner, Collin Davidson, F. Tillman","doi":"10.1144/geochem2023-007","DOIUrl":"https://doi.org/10.1144/geochem2023-007","url":null,"abstract":"Breccia pipe deposits of the Grand Canyon region contain ore grade copper and uranium. Horn Creek is located near the Orphan Mine mineralized breccia pipe deposit and groundwater emerging from the bedrock in the headwaters of Horn Creek has the highest uranium concentrations in the region. Uranium decreases an order of magnitude between the groundwater at the top of the watershed and the groundwater emerging from the alluvial material lower in the watershed. Horn Creek water has low sulfur and uranium isotopic ratios which may suggest interaction with sulfide and uranium minerals found in mineralized breccia pipe deposits. Per- and polyfluoroalkyl substances (PFBA and PFBS) were found in low concentrations in groundwater from the bedrock and may be related to mining process materials or other anthropogenic activities. PHREEQC modeling suggests that water that is elevated in uranium emerging from the bedrock in the upper watershed may mix with other groundwater and atmospheric precipitation infiltrated into the alluvial material in the lower watershed. Tritium is elevated in Horn Creek groundwaters suggesting a component of modern water, some of which may have interacted with Orphan Mine workings. Additional studies could build on this understanding of chemistry changes in waters of Horn Creek to provide more direct evidence of contribution of water moving through the Orphan Mine.\u0000 \u0000 Thematic collection:\u0000 This article is part of the Geochemical processes related to mined, milled, or natural metal deposits collection available at:\u0000 https://www.lyellcollection.org/topic/collections/geochemical-processes-related-to-mined-milled-or-natural-metal-deposits\u0000 \u0000 \u0000 Supplementary material:\u0000 https://doi.org/10.6084/m9.figshare.c.6747638\u0000","PeriodicalId":55114,"journal":{"name":"Geochemistry-Exploration Environment Analysis","volume":" ","pages":""},"PeriodicalIF":2.4,"publicationDate":"2023-07-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48727846","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Mary E. Doherty, Kiel Arndt, Z. Chang, K. Kelley, O. Lavin
Stream sediment surveys support early-stage reconnaissance mineral exploration and regional assessment programs, enhanced by recent improvements in analytical method detection limits, continuously improving mineral chemistry, and new approaches to the interpretation of geochemical data. Sediment surveys may be used to predict catchment basin lithology, mineralization type based on pathfinder geochemistry, and geological features based on indicator mineral chemistry. Sediment surveys that target a finer fraction sediment sample led to discovery of the La Colosa gold deposit, Colombia. The Batu Hijau porphyry Cu-Au deposit in Indonesia was discovered based on an anomalous clay-sized fraction sample 12 km downstream. In an arid region with poorly developed drainages and minor topographic relief, the Ag-base-metal Navidad District in Argentina was discovered with clay-fraction sediment geochemistry. Heavy mineral concentrate sediment surveys (HMC) that include mineral chemistry determinations have led to global diamond discoveries. HMC surveys contributed to discovery of the Ring of Fire Ni-Cu-PGE and chromite district, Ontario Canada. Discoveries and geochemical mapping can assist advancement of the application of stream sediment geochemistry in those global areas for which lithologies and deposits are exposed. Stream sediment surveys continue to be one of the most cost-effective geochemical methods for covering large areas for mineral exploration. Thematic collection: This article is part of the Reviews in Exploration Geochemistry collection available at: https://www.lyellcollection.org/topic/collections/reviews-in-exploration-geochemistry
{"title":"Stream sediment geochemistry in mineral exploration: a review of fine-fraction, clay-fraction, bulk leach gold, heavy mineral concentrate and indicator mineral chemistry","authors":"Mary E. Doherty, Kiel Arndt, Z. Chang, K. Kelley, O. Lavin","doi":"10.1144/geochem2022-039","DOIUrl":"https://doi.org/10.1144/geochem2022-039","url":null,"abstract":"Stream sediment surveys support early-stage reconnaissance mineral exploration and regional assessment programs, enhanced by recent improvements in analytical method detection limits, continuously improving mineral chemistry, and new approaches to the interpretation of geochemical data. Sediment surveys may be used to predict catchment basin lithology, mineralization type based on pathfinder geochemistry, and geological features based on indicator mineral chemistry. Sediment surveys that target a finer fraction sediment sample led to discovery of the La Colosa gold deposit, Colombia. The Batu Hijau porphyry Cu-Au deposit in Indonesia was discovered based on an anomalous clay-sized fraction sample 12 km downstream. In an arid region with poorly developed drainages and minor topographic relief, the Ag-base-metal Navidad District in Argentina was discovered with clay-fraction sediment geochemistry. Heavy mineral concentrate sediment surveys (HMC) that include mineral chemistry determinations have led to global diamond discoveries. HMC surveys contributed to discovery of the Ring of Fire Ni-Cu-PGE and chromite district, Ontario Canada. Discoveries and geochemical mapping can assist advancement of the application of stream sediment geochemistry in those global areas for which lithologies and deposits are exposed. Stream sediment surveys continue to be one of the most cost-effective geochemical methods for covering large areas for mineral exploration.\u0000 \u0000 Thematic collection:\u0000 This article is part of the Reviews in Exploration Geochemistry collection available at:\u0000 https://www.lyellcollection.org/topic/collections/reviews-in-exploration-geochemistry\u0000","PeriodicalId":55114,"journal":{"name":"Geochemistry-Exploration Environment Analysis","volume":" ","pages":""},"PeriodicalIF":2.4,"publicationDate":"2023-06-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45868518","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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