Journal of Geochemical Exploration最新文献

{"title":"A hydrogeochemical and isotopic approach for assessing the origin, recharge and mixing process of geothermal water in the Yinchuan Basin","authors":"Yiwen Zhu ,&nbsp;Qingchun Yang ,&nbsp;Xinzhu Chang ,&nbsp;Weijun Hao ,&nbsp;Yuxue Ma ,&nbsp;Jordi Delgado Martín","doi":"10.1016/j.gexplo.2024.107636","DOIUrl":"10.1016/j.gexplo.2024.107636","url":null,"abstract":"<div><div>The hydrogeochemistry of geothermal fluids is fundamental to reveal the genesis, recharge mechanism and circulation pattern of geothermal water. However, the origin and hydrogeochemical process of geothermal water in deep aquifer system still remain unclear. In this study, 17 water samples were analyzed to study the origin, recharge and mixing process of geothermal water in the Yinchuan basin by using a hydrogeochemical and isotopic approach. The results showed that the concentrations of major ions (SO₄²⁻, Na⁺, Cl⁻, TDS, Ca²⁺, K⁺, Mg²⁺ and NH₄⁺) and trace elements (Li, F⁻, Br⁻, I⁻, Sr and Mn) in geothermal water are significantly greater than those in shallow water, hot spring and cold spring in the study area. The hydrochemical type of geothermal water is dominated by Cl·SO₄-Na, which is mainly influenced by dissolution of halides, chlorides and sulfates under strong fluid-rock interactions. The isotope analysis demonstrated that the atmospheric precipitation in the Helan Mountain area is the major recharge source of geothermal water, the recharge elevation is 1118 m–1133 m, and the deep geothermal water is formed by a mixing process of ancient precipitation and modern precipitation. The silica-enthalpy mixing model suggested that the reservoir temperature of deep geothermal fluid is between 110 °C and 175 °C, and the mixing ratio of cold water is about 54 % to 92 %. The present study sheds some light on the genesis, recharge mechanism and hydrogeochemical evolution of geothermal water in deep aquifers, which are vital for sustainable exploitation and utilization of geothermal resources.</div></div>","PeriodicalId":16336,"journal":{"name":"Journal of Geochemical Exploration","volume":"269 ","pages":"Article 107636"},"PeriodicalIF":3.4,"publicationDate":"2024-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142719866","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Metal nanoparticles in soil: Indicators of concealed mineral deposits","authors":"Bimin Zhang ,&nbsp;Yuexin Lu ,&nbsp;Xueqiu Wang ,&nbsp;Jian Zhou ,&nbsp;Hongwei Li","doi":"10.1016/j.gexplo.2024.107633","DOIUrl":"10.1016/j.gexplo.2024.107633","url":null,"abstract":"<div><div>Nanogeology represents a cutting-edge scientific discipline characterized by its multi-disciplinary nature. This study provides an overview of the characteristics and behaviors of metal-bearing nanoparticles in soils above different ore deposits in China. It discusses the proposed origins, migration, and precipitation of these nanoparticles, as well as their applications in mineral exploration. Additionally, this study highlights the challenges and prospects of metal-bearing nanoparticles used in the mineral exploration.</div><div>Metal-bearing nanoparticles, which contain varying proportions of ore-related elements (e.g., Au, Ag, Cu, Pb and Zn) are rarely found in natural settings unrelated to ore bodies or mineral extraction. Due to the compositional similarity between metal-bearing nanoparticles in soil and likely link to concealed ore bodies, these nanoparticles can be effectively sampled in the soil, to understand the properties of the deeper concealed mineralization. Therefore, metal-bearing nanoparticles can serve as effective indicators of buried deposits. These nanoparticles may migrate from deep ore bodies to the surface through multi-process relay mechanisms, including geogas flow, atmospheric pressure pumps, electrochemical processes, and plant transpiration. They accumulate in fine-grained soil fractions with larger surface areas and adsorptive potential, such as clay minerals and organic matter, making fine-grained soil an important sink for metal-bearing nanoparticles. By separating fine-grained soil, the intensity of geochemical anomalies can be increased, thereby enhancing the accuracy of mineral exploration. Current research predominantly provides qualitative descriptions of nanoparticle characteristics, lacking quantitative analysis methods. Future efforts should focus on using high-resolution technologies such as Nano Scale Secondary Ion Mass Spectrometry (NanoSIMS), Atom Probe Tomography (APT), Focused Ion Beam Scanning Electron Microscopy (FIB-SEM), and synchrotron radiation to conduct detailed studies on the isotopic composition, internal structure, and elemental coupling relationships of nanoparticles. This approach will allow for better tracing of their origins and realize their potential in mineral exploration.</div></div>","PeriodicalId":16336,"journal":{"name":"Journal of Geochemical Exploration","volume":"269 ","pages":"Article 107633"},"PeriodicalIF":3.4,"publicationDate":"2024-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142720927","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Genetic link between concealed granite and tin mineralization in the Yuling tin deposit, Nanling Range, South China: Constraints from zircon and cassiterite U-Pb dating, geochemistry, and Lu-Hf isotopes","authors":"Yong-Kang Chen ,&nbsp;Pei Ni ,&nbsp;Jun-Yi Pan ,&nbsp;Yi-Ming Xu ,&nbsp;Qi-Zhi Yang ,&nbsp;Jian-Ming Cui ,&nbsp;Wen-Sheng Li ,&nbsp;Guan-Jian Fang","doi":"10.1016/j.gexplo.2024.107627","DOIUrl":"10.1016/j.gexplo.2024.107627","url":null,"abstract":"<div><div>The Nanling Range in South China is a world-renowned tin (Sn)-tungsten (W) metallogenic belt. The Yuling deposit is a representative Sn deposit newly discovered in the Nanling Range in recent years. The mineralization of Sn and accompanied Pb-Zn(-Sb) is controlled by faults and hosted in shallow metamorphic sandstone of the Cambrian, with concealed granitic intrusion in the deep. Here, we report for the first time precise in-situ U-Pb dating of zircon and cassiterite, petrogeochemistry, zircon trace element and Hf isotope data from the Yuling Sn deposit to clarify the genetic link between Sn mineralization and the concealed biotite granite. The U-Pb ages of the concealed granite and Sn mineralization are 155.1 ± 0.7 Ma and 154.4 ± 1.4 Ma, respectively, indicating that Sn mineralization occurred simultaneously with Late Jurassic granitic magmatism. Combined with the geological observation that Sn mineralization developed locally near the roof of concealed granite, further attests to the close genetic link between the Yuling Sn deposit and the deep-seated concealed granite. The zircon ε_Hf(t) values range from −5.14 to −1.37 (mean = −2.87), and the two-stage Hf mode ages (T_DM2) range from 1.29 to 1.52 Ga (mean = 1.38 Ga), indicating that the source rocks of the Yuling granite primarily originated from the remelting of ancient crustal rocks in the Mesoproterozoic of South China, with the involvement of some juvenile mantle-derived components. The Yuling granite exhibits high content of SiO₂, K₂O, K₂O + Na₂O, low content of MgO, CaO, Ba, Sr, Ni, Cr, relatively flat REE patterns and significant negative Eu anomalies. Petrographic and whole-rock geochemical data show that the Yuling granite has an A₂-type granite affinity and formed in an intraplate extensional setting of intense crust-mantle interaction similar to that of numerous A₂-type granites associated with Sn-W mineralization during the early Yanshanian in the Nanling Range. It may be related to the extension and thinning of the continental lithosphere and asthenosphere upwelling induced by northwestward subduction of the paleo-Pacific plate. Moreover, the factors controlling the Sn mineralization potential of granitic magma were evaluated using zircon trace elements and petrogeochemical data. These findings indicate that the Yuling granite crystallized from higher temperature, lower water content, F-rich, and highly-fractionated reduced granitic magma. Such granitic magma is conducive to generating Sn-rich fluids and has high Sn mineralization potential.</div></div>","PeriodicalId":16336,"journal":{"name":"Journal of Geochemical Exploration","volume":"269 ","pages":"Article 107627"},"PeriodicalIF":3.4,"publicationDate":"2024-11-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142719983","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Differentiating Triassic W–Sn ore-bearing and ore-free plutons in the Xitian Ore Field (South China) using apatite geochemistry","authors":"Xiaojun Hu ,&nbsp;Huan Li ,&nbsp;Thomas J. Algeo ,&nbsp;Biao Liu ,&nbsp;Fan Kang ,&nbsp;Yiming Xie ,&nbsp;Dapeng Zhu","doi":"10.1016/j.gexplo.2024.107628","DOIUrl":"10.1016/j.gexplo.2024.107628","url":null,"abstract":"<div><div>Though the metallogenic process of the Xitian W–Sn deposit has been established, the key factors distinguishing Triassic W–Sn ore-bearing granites from ore-free granites remain uncertain, leaving an important gap in understanding the controls on Triassic W–Sn mineralization. In this study, we present a comprehensive investigation of apatite from the Triassic Longshang W–Sn ore-bearing and Goudalan ore-free granites, to trace the nature of parental magma and to provide constraints on the processes related to Triassic W–Sn mineralization in Xitian Ore Field (South China). Apatites from ore-bearing (AOB) granites and apatites from ore-free (AOF) granites exhibit distinct Cathodoluminescence (CL) images: AOB samples feature darker cores and brighter rims, with concentric oscillatory growth zoning in the rim sections, whereas AOF samples exhibit chaotic textures in CL images. The U–Pb age dating of AOB and AOF yield a lower intercept age of 227.3 ± 4.3 Ma (1σ, MSWD = 3.9) and 227.1 ± 7.8 Ma (1σ, MSWD = 2.4) on the Tera-Wasserburg diagrams, respectively. The similar ε_Nd(t) values (−10.91 to −9.82 for AOB; −10.42 to −8.77 for AOF) (expressed as deviation in parts per 10,000 from CHUR composition), relatively low Cl contents (&lt;0.05 wt%), and high F (~3 wt%) of studied apatites, suggest that W–Sn ore-bearing and ore-free granitic magmas were both generated by melting of old continental crust. The texture and high concentration of REE + Y and Th in AOB could be assumed as the result of fluid exsolution. The chaotic texture, broad variation in ¹⁴⁷Sm/¹⁴⁴Nd ratios, may imply that AOF might have experienced metasomatic modification. Lower Eu/Eu* value together with higher Ce/Ce* value in AOB suggests a more reduced environment for W–Sn ore-bearing granites. Lower Sr, Mg content, and higher Y contents suggest that W–Sn ore-bearing granites have a higher degree of fractionation than ore-free granites. We propose that the mobilization and transport ability of W and Sn by hydrothermal fluids play an important role in the enrichment of W and Sn, and redox state of magma and the degree of magma differentiation determine the final enrichment level of tungsten and tin.</div></div>","PeriodicalId":16336,"journal":{"name":"Journal of Geochemical Exploration","volume":"268 ","pages":"Article 107628"},"PeriodicalIF":3.4,"publicationDate":"2024-11-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142664303","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Calcium change of transported soils from 1995 to 2010 in acid rain areas in China","authors":"Xuemin Liu ,&nbsp;Xueqiu Wang ,&nbsp;Bimin Zhang ,&nbsp;Miao Xie ,&nbsp;Fang Yang ,&nbsp;Liang Tang","doi":"10.1016/j.gexplo.2024.107629","DOIUrl":"10.1016/j.gexplo.2024.107629","url":null,"abstract":"<div><div>Acid rain, a significant environmental threat, negatively impacts soil health and ecosystems. It can leach calcium (Ca) from soils, affecting plant growth and other ecological processes. China has experienced widespread acid rain, particularly in the southern regions. Two national geochemical mapping projects: Environmental Geochemical Monitoring Networks (EGMON) and China Geochemical Baselines (CGB), were conducted to establish baselines for soil Ca. This study compares these baselines to quantify Ca changes in China's acid rain areas from 1995 to 2010 and identify key controlling factors. Our analysis revealed a significant decrease in Ca content in transported soils across these regions during this period. Notably, the median Ca concentration in the top soil (TS) decreased from 0.47 % to 0.36 %, and in the deep soil (DS) from 0.39 % to 0.31 %. Areas experiencing Ca depletion contents were roughly twice as those with increases. Estimated net Ca change rates were −0.07 Pg/a for TS and 0.04 Pg/a for DS, indicating a net Ca loss of 1.25 Pg from the study region's top 125 cm of soil. This translates to a loss rate of 0.083 Pg/a or 0.026 g Ca²⁺ kg⁻¹ soil per year. Calcium contents in transported soils were influenced by the interplay of acid rain, rainfall, and parent rocks. Acid rain could dissolve Ca from carbonate-rich rocks, enriching nearby rivers with Ca²⁺. Upon deposition, clay minerals in the soils could adsorb Ca²⁺, potentially increasing soil Ca content. However, intense acid rain (pH &lt;5.0) could leach Ca²⁺ from the soil and outweigh the positive influence of parent carbonate-rich rocks, leading to Ca depletion. Additionally, in regions with sufficient rainfall (&gt;1600 mm/a), combined with the leaching effect of acid rain, Ca content could decrease due to overall mobilization and transport out of the soil.</div></div>","PeriodicalId":16336,"journal":{"name":"Journal of Geochemical Exploration","volume":"269 ","pages":"Article 107629"},"PeriodicalIF":3.4,"publicationDate":"2024-11-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142719869","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Recycled mantle source for porphyry mineralization: U−Pb and Re−Os geochronology, and S–Pb–Cu isotopic constraints from the Urumieh-Dokhtar magmatic arc, central Iran","authors":"Shahrouz Babazadeh ,&nbsp;Davood Raeisi ,&nbsp;M. Santosh ,&nbsp;Miao Zhao ,&nbsp;Massimo D'Antonio","doi":"10.1016/j.gexplo.2024.107630","DOIUrl":"10.1016/j.gexplo.2024.107630","url":null,"abstract":"<div><div>The Urumieh−Dokhtar magmatic arc (UDMA) hosts some of the world-class porphyry copper deposits in Iran. Here, we present high-resolution geochronological and stable isotope data to gain insights into the timing and source of the metallogeny of Kahang porphyry Cu deposit. Zircon U−Pb data show crystallization age of <em>ca.</em> 15 Ma age for the host porphyry intrusion and Re−Os geochronology yields 14.5 Ma from the molybdenite associated with the ores. Sulfur isotope values on the sulphide minerals range from −1.6 ‰ to + 2.1 ‰, indicating a magmatic source for sulfur. Lead isotopic compositions of the S-bearing minerals are akin to those of the intrusive rocks, suggesting that the metal was likely sourced from mantle reservoirs. We propose a model for the UDMA involving slab break-off during the maturity of arc magmatism from the <em>syn</em>- to <em>post</em>-collisional stages of orogenesis. The δ⁶⁵Cu data trace a systematic change from the barren to the fertile magmas. We suggest that partial melting of the sub-continental lithospheric mantle that has previously been refertilized of Cu through time as the potential source for the formation of ore-bearing magmas.</div></div>","PeriodicalId":16336,"journal":{"name":"Journal of Geochemical Exploration","volume":"268 ","pages":"Article 107630"},"PeriodicalIF":3.4,"publicationDate":"2024-11-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142664323","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Implications for metallogenic evolution of the Balong gold deposit, East Kunlun metallogenic belt: Insights from in-situ trace elements and S isotopes of sulfides","authors":"Yanyan Zhao ,&nbsp;Jun Tan ,&nbsp;Mingyu Xin ,&nbsp;Yan Liu ,&nbsp;Ming Zhang ,&nbsp;Xiaoyang Liu ,&nbsp;Ziqing Yan ,&nbsp;Xiliang Jia","doi":"10.1016/j.gexplo.2024.107626","DOIUrl":"10.1016/j.gexplo.2024.107626","url":null,"abstract":"<div><div>The Balong gold deposit is one of numerous lode gold deposits in the East Kunlun metallogenic belt. Gold mineralization is hosted in Triassic granitoids, typified by auriferous quartz veins. Hydrothermal alteration includes sericite, quartz, sulfide, chlorite, and calcite. Pyrite, as the most abundant sulfide in the ore, is sometimes seen in the company of arsenopyrite. Three types of pyrite have been identified. The porous Py1 exhibits low Co and Ni contents, with an absence of gold. Subhedral Py2-1 shows higher Co (median 80 ppm) and Ni (median 10.5 ppm) contents and contains various Cu-Pb-Zn-Ag mineral inclusions. Py2-2 shows an increase in As (median 17, 073 ppm) and Au (median 3.79 ppm), exhibiting obvious distinctions between Py2-1 and Py2-2.</div><div>Gold in the Balong deposit consists of both visible and invisible gold. Gold occurs within micro-fractures of pyrite and arsenopyrite, appearing as irregular inclusions or as infillings. Apart from visible gold grains, the majority of invisible gold hosted in Py2-2 occurs as solid solutions (Au⁺). Coupled dissolution-reprecipitation reactions of early pyrite are a key factor for visible gold precipitation and later invisible gold enrichment. Pyrite records a narrow range of <em>δ</em>³⁴S values from −1.6 to 5.4 ‰, reflecting sulfur from a deep magmatic source. These findings indicate a connection between the ore-forming materials and the evolved magmatic-hydrothermal fluids.</div></div>","PeriodicalId":16336,"journal":{"name":"Journal of Geochemical Exploration","volume":"269 ","pages":"Article 107626"},"PeriodicalIF":3.4,"publicationDate":"2024-11-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142719982","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Using UAVs to collect filtered water samples for mineral exploration: Will it take off?","authors":"James A. Kidder ,&nbsp;Alain Grenier ,&nbsp;Bradley J.A. Harvey ,&nbsp;Christopher E. Beckett-Brown ,&nbsp;M. Beth McClenaghan ,&nbsp;Pierre Pelchat ,&nbsp;Jing Zhang ,&nbsp;Daniel Layton-Matthews ,&nbsp;Frank Oliva","doi":"10.1016/j.gexplo.2024.107617","DOIUrl":"10.1016/j.gexplo.2024.107617","url":null,"abstract":"<div><div>The advent of unmanned aerial vehicle (UAV) assisted surface water sampling and ongoing technological advances in sampling and data acquisition, offers many opportunities to conduct high-quality hydrogeochemical surveys with low cost, high efficiency, and reduced human interactions. Hydrogeochemical mineral exploration is one area that could greatly benefit from a UAV sampling revolution, with survey sites often located in highly remote areas with limited existing infrastructure. Currently, a lack of point source filtration and complicated physiochemical data acquisition hinder mainstream UAV deployment in the context of hydrogeochemical studies. The aim of this paper is to provide guidance on effective UAV sampling methods and physiochemical data collection for use in surface water hydrogeochemical mineral exploration. To date, case study surveys have utilized sampling systems where sampled waters are filtered after collection or analyzed for ‘total’ (unfiltered) concentrations. This paper details a methodology for point-source filtration of water samples using a UAV system to recover filter sample aliquots for the determination of ‘dissolved’ (&lt;0.45 μm) trace element concentrations and compares UAV methods to conventional sampling strategies. This study systematically compares the quality of analytical data collected from lakes, ponds, and rivers in the Long Lake area of southern Ontario, using conventional manual sampling (from a boat or canoe) and a series of UAV-based sampling methodologies. The waters sampled within the study area are highly meteoric and show evidence of solute input from water-rock interaction with local country rocks. The results of this study show that in general, conventional sampling methodologies are statistically comparable to samples collected using UAVs. However, there is some evidence of element variation related to lake stratification, with dissolved Cu concentrations higher in samples collected at depth compared to those from the surface. Similarly, samples filtered after collection typically have lower concentrations of Fe and Mn, potentially resulting from precipitation before filtration. An enclosed sampling system offered from peristaltic pumping with in-line filtration removes the potential for contamination from the surrounding environment and from the UAV itself.</div></div>","PeriodicalId":16336,"journal":{"name":"Journal of Geochemical Exploration","volume":"269 ","pages":"Article 107617"},"PeriodicalIF":3.4,"publicationDate":"2024-11-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142748596","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Numerical simulation of a base metal deposit related to a fossil geothermal system","authors":"David Calisto ,&nbsp;Daniel Moncada ,&nbsp;Eric Sonnenthal ,&nbsp;Lorena Ortega ,&nbsp;Darío Chinchilla","doi":"10.1016/j.gexplo.2024.107613","DOIUrl":"10.1016/j.gexplo.2024.107613","url":null,"abstract":"&lt;div&gt;&lt;div&gt;Fossil and active geothermal systems that produce ore deposits are sites of complex physicochemical processes and a favorable combination of factors related to the amount of metal-bearing fluid that flows through the system, ore fluid metal concentrations, depositional efficiency, and the duration of ore deposition. Of all these factors, the length of the mineralizing event is one of the least understood aspects of ore genesis.&lt;/div&gt;&lt;div&gt;We used fluid inclusion data, chemical compositions of base metal sulfides, and fluid flow rates to constrain a reactive-transport model of a fossil geothermal system - the Patricia Zn-Pb-Ag deposit in northern Chile. The Patricia deposit consists of quartz and base metal sulfide veins of hydrothermal origin with structural control, hosted in a volcanic succession with intense propylitic alteration. The fluid inclusions are liquid-rich, with homogenization temperatures ranging from 250 to 150 °C and salinities between 22 and 1 wt% NaCl equiv., with an early fluid mixing trend and no evidence of boiling in the system. Sulfide mineralogy indicates intermediate sulfidation conditions.&lt;/div&gt;&lt;div&gt;To identify the most relevant geochemical and transport parameters controlling the formation of this fossil geothermal system &gt;1000 simulations were performed using the reactive-transport code TOUGHREACT. The paragenesis of the deposit is mimicked by a model of successive stages of fluid circulation consistent with the observed mineral assemblage distribution, the fluid inclusion data, and the estimated resources in the deposit.&lt;/div&gt;&lt;div&gt;The entire geothermal activity of the system was modeled considering 10,000 years of fluid-rock interaction, with periods of circulation of metal-barren fluids followed by metal-rich fluids driving the ore formation. In the initial model, base metal solubility with predominant chloride complexing suggests that the most efficient ore-forming mechanism for the Patricia deposit was the result of the interaction of two different fluids, one fluid transporting metals and another fluid transporting reduced sulfur, mixing in a rock volume of high permeability. Mass balance estimations with this model give a period of 3500 to 5000 years for the ore stage duration in which all the ore resources of the Patricia deposit could have been precipitated by fluid mixing.&lt;/div&gt;&lt;div&gt;In a second model, the previous estimates for the duration of the main ore stage were used to simulate the fluid-rock interaction during the ore stage for 3500 years. The results indicated the importance of the permeability of the host rock enhanced by fractures to concentrate the volume of the mineralization and the role of the hydrothermal alteration assemblage in controlling the circulating fluid acidity. A higher efficiency in forming sulfide minerals appears to coincide with pH values ranging from 5.1 to 5.3.&lt;/div&gt;&lt;div&gt;The results of both models are validated by replicating the system evolution, reproducing the sa","PeriodicalId":16336,"journal":{"name":"Journal of Geochemical Exploration","volume":"268 ","pages":"Article 107613"},"PeriodicalIF":3.4,"publicationDate":"2024-11-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142664311","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effect of passive jaw opening on the electromyographic activity of the temporalis, masseter, digastric, and infrahyoid muscles in healthy adults.","authors":"Jeong-Seung Kwon, Sang-Ho Han, Yeong-Gwan Im","doi":"10.1080/08869634.2022.2048225","DOIUrl":"10.1080/08869634.2022.2048225","url":null,"abstract":"<p><strong>Objective: </strong>To investigate the surface electromyography (EMG) activity of the temporalis, masseter, digastric, and infrahyoid muscles during passive jaw opening in healthy adults.</p><p><strong>Methods: </strong>The EMG activity of the masseter, temporalis, digastric anterior belly, and infrahyoid muscles on the right side was recorded during the four jaw-opening tasks: active opening to 20 mm (AO20); active opening to 40 mm (AO40); passive opening to 40 mm with a rubber mouth prop on the right posterior teeth (POR40); and passive opening to 40 mm with a mouth prop on the left posterior teeth (POL40).</p><p><strong>Results: </strong>The EMG amplitude of the digastric anterior belly and infrahyoid muscles in either POL40 or POR40 was significantly less than that in AO20 or AO40, respectively.</p><p><strong>Conclusion: </strong>Passive jaw opening reduces the EMG activity of the digastric and infrahyoid muscles significantly and could help reduce the load on these muscles during prolonged mouth-opening conditions.</p>","PeriodicalId":16336,"journal":{"name":"Journal of Geochemical Exploration","volume":"174 1","pages":"736-744"},"PeriodicalIF":2.0,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86959825","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}