Geoscience frontiers最新文献

{"title":"Detection of Earth’s free oscillation and analysis of the non-synchronous oscillation phenomenon of normal modes","authors":"Yingqi Zhang ,&nbsp;Gong Xu ,&nbsp;Chenchen Wang ,&nbsp;Yaxin Zhao ,&nbsp;Zheng Mu ,&nbsp;Yunhao Fan ,&nbsp;Changwei Jing","doi":"10.1016/j.gsf.2024.101957","DOIUrl":"10.1016/j.gsf.2024.101957","url":null,"abstract":"<div><div>Earth’s free oscillation can provide essential constraints for refining Earth models, inverting seismic source mechanisms, and studying the deep internal structure of the Earth. Large earthquakes can simultaneously excite numerous normal modes. Due to the Earth’s ellipticity, rotation, and internal heterogeneities, these normal modes undergo splitting, with the frequencies of singlets of normal modes becoming very close (only a few µHz apart). This imposes greater demands on the detection of normal modes. This paper introduces a novel method for normal mode detection based on the normal time–frequency transform (NTFT). Compared to classical FT spectrum methods and recent optimal sequence estimation (OSE), the proposed method not only detects more weak normal modes but also reveals the spatial distribution of the phase of each normal mode. Taking the detection of ₀S₂ as an example, the phase measurements of each singlet are spatially inconsistent. This phenomenon can provide prior information for other methods, such as product spectrum analysis (PSA), spherical harmonic stacking (SHS), multistation experiments (MSE), and OSE. Additionally, understanding the phase distribution patterns contributes to further study of geological structures, offering crucial foundational data and observational support.</div></div>","PeriodicalId":12711,"journal":{"name":"Geoscience frontiers","volume":"16 1","pages":"Article 101957"},"PeriodicalIF":8.5,"publicationDate":"2024-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142654792","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Analyzing failure mechanisms and predicting step-like displacement: Rainfall and RWL dynamics in lock-unlock landslides","authors":"Xuekun Xiang ,&nbsp;Haijia Wen ,&nbsp;Jiafeng Xiao ,&nbsp;Xiongfeng Wang ,&nbsp;Hongyue Yin ,&nbsp;Junhao Huang","doi":"10.1016/j.gsf.2024.101959","DOIUrl":"10.1016/j.gsf.2024.101959","url":null,"abstract":"<div><div>Lock-unlock landslides have thick sliding zones that store a lot of energy. This makes them start quickly, happen suddenly, and have serious consequences. Therefore, it becomes urgent to study the deformation and failure mechanisms of such landslides and develop rational predictive models. Taking the Jiuxianping landslide as an example, this study investigates the regularity of landslide displacement changes using multi-source data, focusing on the abrupt displacement patterns in the unlock phase. Furthermore, employing Transient Release and Inhalation Method tests combined with Geo-Studio’s SEEP/W and SIGMA/W modules for fluid–solid coupled simulation calculations, the evolution process of landslide failure mechanisms and deformation characteristics is analyzed and discussed. Lastly, utilizing data mining analysis of multi-source data, a hybrid optimized machine learning predictive model is established for model prediction comparison. The study reveals that: (1) The rise in infiltration line elevates pore water pressure, affecting the stability of the sliding zone, leading to “unlock effects” and step-like displacement deformation; (2) Simulation shows that YY208 is closer to the actual situation, located at the far bank position, while YY210 is greatly influenced by the “buoyancy effect”, resulting in a slowdown in deformation velocity; (3) After data preprocessing, overall actual displacement prediction performs better than simulation displacement prediction in terms of Mean Absolute Error, Mean Squared Error and Correlation Coefficient, but noise reduction processing can improve the periodic prediction effect of simulation displacement.</div></div>","PeriodicalId":12711,"journal":{"name":"Geoscience frontiers","volume":"16 1","pages":"Article 101959"},"PeriodicalIF":8.5,"publicationDate":"2024-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142654796","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Aerosol spatiotemporal dynamics, source analysis and influence mechanisms over typical drylands","authors":"Yunfei Zhang ,&nbsp;Xiangyue Chen ,&nbsp;Fengtao Zhao ,&nbsp;Qianrou Xia ,&nbsp;Hanchen Xing ,&nbsp;Mengdi Du","doi":"10.1016/j.gsf.2024.101958","DOIUrl":"10.1016/j.gsf.2024.101958","url":null,"abstract":"<div><div>As globally important dust source areas, drylands not only have extremely fragile ecosystems that are exceptionally sensitive to global climate change but also have important implications for global warming and carbon cycling. However, the detailed dryland aerosol characteristics are not clear, especially the influence mechanisms of dryland aerosols, which are poorly understood. In this paper, Utilizing the Xinjiang Uygur Autonomous Region (XJ) as a target area, based on high spatial resolution aerosol optical depth (AOD) data, combined with the trend analysis, backward trajectory, source analysis, and machine learning methods, we systematically analyzed the multiscale dynamic characteristics of aerosols in XJ over a long period. Simultaneously, we also quantitatively explored the source distributions of high aerosols at typical sites at different time scales. Furthermore, we discussed the specific effects of natural and anthropogenic factors on aerosols in XJ and its subregions. The results show that 72.45% of the AOD in XJ presents an increasing trend from 2000 to 2019, 27.56% of which passed the significance test, mainly concentrated in northern Xinjiang (NXJ). The AOD in southern Xinjiang (SXJ) is the largest (0.240 ± 0.154), followed by eastern Xinjiang (EXJ) (0.157 ± 0.038), and the AOD in NXJ is the smallest (0.134 ± 0.028); however, the AOD in NXJ has the most obvious increasing trend, peaking in 2011, and the AOD in XJ remains low and stable at 5000 m elevation and above. The backward trajectory shows that nearly half of the potential paths of high AOD in SXJ are from the Taklamakan Desert, most of the potential paths in NXJ are from transboundary transmission, mostly through exposed lake beds, and most of the potential paths in EXJ are from the northwest, with characteristics similar to those of NXJ. The exposed lake beds provide salt dust, which further exacerbates the complexity and hazards of aerosols in NXJ and EXJ. The potential source areas for AOD in SXJ are concentrated in the northeast of the target site, those in NXJ are concentrated in the west of the target site, and those in EXJ are in the northwest and east. The AOD in SXJ (63.92%) and EXJ (74.83%) or XJ (57.77%) is dominated by natural factors, whereas the magnitude of AOD in NXJ (84.01%) is largely explained by anthropogenic factors.</div></div>","PeriodicalId":12711,"journal":{"name":"Geoscience frontiers","volume":"16 1","pages":"Article 101958"},"PeriodicalIF":8.5,"publicationDate":"2024-10-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142654795","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Do we really need to drill through the intact ocean crust?","authors":"Yaoling Niu","doi":"10.1016/j.gsf.2024.101954","DOIUrl":"10.1016/j.gsf.2024.101954","url":null,"abstract":"<div><div>We must persevere to drill through the intact ocean crust to fully address fundamental questions towards completion of the plate tectonics theory. The primary questions include: what is the ocean crust made up of, how thick is it and what is the petrological nature of the crust-mantle boundary (i.e., Mohorovičić discontinuity or Moho)? These questions may sound naive because they are widely believed to be well-understood facts, but they are not. Correctly, our current knowledge remains incomplete, and some popular misperceptions come from interpretations based on convenient assumptions. One assumption is that the ocean crust inferred from seismic data is of magmatic origin. Testing this assumption is a principal motivation of <em>Project Mohole</em> (1957–1966), attempting to drill intact ocean crust across the Moho into the mantle. <em>Project Mohole</em> failed because of its high cost, engineering challenges and insufficient tries, but the technologies developed made subsequent ocean drilling successful. However, answers to the original questions remain unsatisfactory. For example, seismic crust interpreted to be of magmatic origin is shown to have globally uniform thickness of 6.0 ± 1.0 km, but crust with such thickness at many slow-spreading ridge segments is dominated by serpentinized mantle peridotites exposed on seafloors. Therefore, the popular view on ocean ridge magmatism must be re-examined, which needs intact ocean crust drilling into the mantle. Drilling at geologically simple sites in the fast-spreading Pacific seafloor is most promising.</div><div>The US-led <em>D/V JOIDES Resolution</em> that has well served the scientific ocean drilling since 1985 is to retire by the end of 2024, but timely the Chinese geoscience community wishes to continue this international endeavor using the purpose-built <em>D/V Meng Xiang</em> to be in service in 2025. The international community is to gather in November 24–27, 2024, Guangzhou, China, to discuss strategies on where and how to successfully drill intact ocean crust across the Moho in coming years.</div></div>","PeriodicalId":12711,"journal":{"name":"Geoscience frontiers","volume":"16 1","pages":"Article 101954"},"PeriodicalIF":8.5,"publicationDate":"2024-10-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142577860","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Combined study of Au-bearing arsenopyrite of orogenic gold deposits (NE Asia): High resolution 3D X-ray computed tomography, LA-ICP-MS, and EMPA data","authors":"Evgeny Naumov ,&nbsp;Yuri Kalinin ,&nbsp;Galina Palyanova ,&nbsp;Lyudmila Kryuchkova ,&nbsp;Viacheslav Voitenko ,&nbsp;Vera Abramova ,&nbsp;Franco Pirajno","doi":"10.1016/j.gsf.2024.101953","DOIUrl":"10.1016/j.gsf.2024.101953","url":null,"abstract":"<div><div>The distribution of gold in small acicular arsenopyrite of a pyrite-arsenopyrite association from Suzdal (Eastern Kazakhstan), Olympiada (Yenisei Ridge, Russia) and large pseudorhombic arsenopyrite crystals from Bazovskoe (Yakutia, Russia) orogenic-type deposits were investigated. On orogenic gold deposits in NE Asia, occurring mainly in black shales, two productive stages of ore deposition are distinguished, which correspond to two morphological varieties of arsenopyrite. At the early stage, fine-grained acicular-prismatic arsenopyrite with invisible gold was deposited; at the late stage, tabular arsenopyrite in association with free visible gold was formed. The samples of gold-bearing arsenopyrite were analyzed using Scanning Electron Microscopy, Electron Microprobe Analyses, Atomic Absorption and Laser Ablation Inductively Coupled Plasma Mass Spectrometry in combination with High Resolution 3D X-ray Computed Tomography (HRXCT). HRXCT does not destroy the studied mineral during the investigation. That technique permits to do an estimation of the amount of gold inclusions in minerals or host rocks and draw reasonable conclusions about the gold content of the ores, to study in detail the distribution patterns of metal inclusions (associated with certain minerals, cracks, crystal growth faces, etc.) and to determine the form of the gold. It can be used to understanding of the genesis of productive mineral associations, and to developing optimal technological schemes for gold extraction.</div></div>","PeriodicalId":12711,"journal":{"name":"Geoscience frontiers","volume":"16 1","pages":"Article 101953"},"PeriodicalIF":8.5,"publicationDate":"2024-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142593158","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Two phases of granulite-facies metamorphism superimposied on retrograde eclogite: Constraints on the early Paleozoic tectonic evolution of the Qinling Orogenic Belt, central China","authors":"Bowen Bai ,&nbsp;Danling Chen ,&nbsp;Yunfei Ren ,&nbsp;Xiaohui Zhu ,&nbsp;Yunpeng Dong ,&nbsp;Yuan Tang ,&nbsp;Haijie Wang","doi":"10.1016/j.gsf.2024.101941","DOIUrl":"10.1016/j.gsf.2024.101941","url":null,"abstract":"<div><div>Existing studies provide adequate petrological evidences on ca. 500 Ma ultra-high pressure (UHP) metamorphism in the North Qinling Orogenic Belt (NQOB) in central China, but the genesis of 470–420 Ma multi-phase granulite-facies metamorphism in the NQOB and their relationship with the ca. 500 Ma UHP metamorphism remain controversial, resulting in the early Paleozoic evolution of the Qinling Orogenic Belt (QOB) highly debatable. In this study, we present mafic granulites and host felsic gneisses with a “red-eye socket” texture from the Shuanglong area, eastern NQOB, which recorded two phases of granulite-facies metamorphism superimposing on former eclogite-facies metamorphism. The former eclogite-facies metamorphism is indicated by eclogite-facies zircon trace element patterns and 496–495 Ma zircon ages, which are the same with those of the HP–UHP eclogite-facies metamorphic rocks in NQOB. The first granulite-facies metamorphism occurred at 460–448 Ma is characterized by coarse-grained minerals in matrix. Compositions and zonings of these minerals define an anticlockwise <em>P–T</em> path involving a prograde stage (751–763 °C), a high-temperature peak stage (9.2 kbar and 864 °C), and a near-isobaric cooling retrograde stage (8.3 kbar and 818 °C). The second granulite-facies metamorphism occurred at 422–421 Ma is represented by coronal garnet and coexisting fine-grained mineral aggregates. Coronal garnet compositional zonings suggest a clockwise <em>P–T</em> path consisting of a high-pressure peak stage (9.5–11.2 kbar and 748–783 °C) and a decompressing and heating retrograde stage (9.2–9.5 kbar and 789–800 °C). Combining dating results of leucosomes in these rocks and existing data, we proposed a new model for early Paleozoic tectonic evolution of the NQOB. The North Qinling Terrane (NQT), probably separated from the South China Block (SCB) during the breakup of Rodinia, drifted northwards and underwent UHP metamorphism at 500 Ma and then rapidly exhumed to crust level. Later, the Shangdan Ocean subducted northwards beneath the exhumed NQT at 470–440 Ma, resulting in the first granulite-facies metamorphism and contemporaneous migmatization and magmatism. Finally, the closure of the Shangdan Ocean led to collision between the NQT and South Qinling Terrane/SCB and the second granulite-facies metamorphism and anatexis at 422–418 Ma.</div></div>","PeriodicalId":12711,"journal":{"name":"Geoscience frontiers","volume":"16 1","pages":"Article 101941"},"PeriodicalIF":8.5,"publicationDate":"2024-10-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142446488","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Paleogeographic significance of unknown hyperextended continental crust in South Atlantic conjugated margin","authors":"C.D. Teixeira ,&nbsp;T.J. Girelli ,&nbsp;H. Serratt ,&nbsp;H.O.S. Oliveira ,&nbsp;M.F. Cruz ,&nbsp;B. Conti ,&nbsp;P. Rodriguez ,&nbsp;F. Chemale Jr","doi":"10.1016/j.gsf.2024.101934","DOIUrl":"10.1016/j.gsf.2024.101934","url":null,"abstract":"<div><div>The paleogeographic reconstruction of fragmented and dispersed continents often poses a challenge due to the lack of information regarding the nature of that extend beneath passive margin basins. To define the width of the continental crust beneath passive margin basins and its implications for paleogeographic reconstruction of conjugate continental margins, this study investigates the architecture of the stretched continental crust of the southern South Atlantic conjugate margin. The investigated region encompasses South Africa, Namibia, southern Brazil, and Uruguay, which were formed during the Mesozoic rifting of SW Gondwana. Employing a multi-tool approach combining seismic interpretation, gravity, magnetometry, and U-Pb isotopic data, the research aims to quantify the extension of stretched continental crust and its implications for plate reconstructions. The study reveals that the restored stretched crust spans at least 150 km, emphasizing the significance of considering connections between both margins for realistic paleogeographic reconstructions. Furthermore, the distinct U-Pb zircon age distribution patterns between SW Africa and SE South America reinforce the lack of direct connections despite their Gondwanan origin. The missing link estimated in this study is around 150 km, comparable in size to major mountain ranges such as the Andean or Urals. This work sheds light on critical aspects of Earth’s dynamic crustal evolution and emphasizes the need for comprehensive reconstructions considering stretched and eroded crust in the South Atlantic conjugate margin.</div></div>","PeriodicalId":12711,"journal":{"name":"Geoscience frontiers","volume":"16 1","pages":"Article 101934"},"PeriodicalIF":8.5,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142551839","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Linking basin-scale hydrology with climatic parameters in western Himalaya: Application of satellite data, temperature index modelling and in-situ observations","authors":"Smriti Srivastava ,&nbsp;Mohd. Farooq Azam ,&nbsp;Praveen Kumar Thakur","doi":"10.1016/j.gsf.2024.101936","DOIUrl":"10.1016/j.gsf.2024.101936","url":null,"abstract":"<div><div>Due to limited spatial and temporal in-situ runoff data availability, Himalaya-Karakoram (HK) glaciohydrology has a significant knowledge gap between large-scale and small-scale runoff modelling studies. This study reconstructs longest basin-wide runoff series in Chandra-Bhaga Basin by applying a high-resolution glaciohydrological model <em>SPHY</em> (Spatial Processes in Hydrology) over 1950–2022. Two-tier model calibration is done using in-situ basin-wide runoff (1973–2006) and MODIS snow cover (2003–2018). Model validation is done against in-situ Chhota Shigri Glacier catchment-wide runoff (2010–2015). The modelled mean annual basin-wide runoff is 60.21 ± 6.17 m³/s over 1950–2022, with maximum runoff in summer-monsoon months, peaking in July (182.69 m³/s). Glacier runoff (ice melt + snowmelt over glacier) contributes maximum (39%) followed by equal contributions from snowmelt runoff from non-glacierized basin area and baseflow (25%), while rainfall-runoff contributes minimum (11 %) to total runoff. There is a significant volumetric increase by ∼7% from pre- (59.17 m³/s) to post-2000 (63.47 m³/s) mainly because of early onset of snowmelt post-2000 that resulted in a hydrograph shift by ∼25 days earlier in spring. The glacier runoff is overestimated by 3% from RGI 7.0 inventory compared to different manually delineated inventories over 1950–2022, because of higher glacierized area from RGI 7.0. The precipitation shows a negative trend, but total runoff shows a positive trend due to positive trend of temperature that resulted in more glacier runoff and rainfall-runoff for basin over last 72 years. Basin-wide runoff is mainly governed by summer temperature which directly controls the amount of glacier and snowmelt runoffs and is supported by summer rainfall. This study highlights importance of basin-scale model calibration with in-situ data in large scale studies and stresses the need for in-situ observations in high-altitude Himalayan region. Basin-scale calibrated model parameters are transferable to glacier catchment scale within Chandra-Bhaga Basin, showing the model robustness at a small catchment scale.</div></div>","PeriodicalId":12711,"journal":{"name":"Geoscience frontiers","volume":"15 6","pages":"Article 101936"},"PeriodicalIF":8.5,"publicationDate":"2024-09-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142421517","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Does energy policy uncertainty matter for renewable energy and energy efficiency technologies? An affordable and clean energy perspective","authors":"Ugur Korkut Pata","doi":"10.1016/j.gsf.2024.101932","DOIUrl":"10.1016/j.gsf.2024.101932","url":null,"abstract":"<div><div>Uncertainty can affect both macroeconomic indicators and the environment. Countries are implementing various energy policies to combat global warming, but these policies contain some uncertainties and contradictions. The environmental impact of uncertainties in energy policies is a research topic that has just begun to be investigated by researchers. This study examines the effects of energy policy uncertainty (ENERPU) on renewable energy R&amp;D (RR&amp;D), energy efficiency R&amp;D (EER&amp;D) and renewable energy consumption in the four countries with the highest RR&amp;D expenditures (USA, Germany, Japan, and Spain). The study uses the novel multivariate quantile-on-quantile (M-QQR) approach from 2003m1 to 2022m9. The results of the study show: (i) The impact of ENERPU varies by quantile and country. (ii) ENERPU causes a decrease in renewable energy consumption and hinders RR&amp;D expenditures. (iii) ENERPU increases EER&amp;D. The Fourier quantile causality test confirms the robustness of the empirical results. Based on these findings, policymakers are recommended to minimize ENERPU and implement stable energy policies to develop the renewable energy sector and technologies.</div></div>","PeriodicalId":12711,"journal":{"name":"Geoscience frontiers","volume":"15 6","pages":"Article 101932"},"PeriodicalIF":8.5,"publicationDate":"2024-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S1674987124001567/pdfft?md5=1474c3a8ce202c140cf440712a3e3a29&pid=1-s2.0-S1674987124001567-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142310460","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Evaluation of environmental geochemical signatures due to RO rejects on arid agricultural farms and tangible solutions","authors":"Harish Bhandary,&nbsp;Chidambaram Sabarathinam,&nbsp;Adnan Akber,&nbsp;Tariq Rashid,&nbsp;Dhanu Radha Samayamanthula,&nbsp;Yogeesha Jayaramu,&nbsp;Bedour Alsabti","doi":"10.1016/j.gsf.2024.101929","DOIUrl":"10.1016/j.gsf.2024.101929","url":null,"abstract":"<div><div>The impact of reverse osmosis (RO) rejects in the groundwater presents a significant challenge in arid regions. This study collected groundwater samples, product water, and reverse osmosis brine (ROB) from evaporation ponds and analyzed them for major ions and trace elements. Test boreholes were drilled near the ROB site along the flow direction, and borehole sediment samples were collected. The samples were predominantly gravelly sand, and the depth to water level fluctuated around 30 m below ground level (bgl), with minerals mainly consisting of calcite, gypsum, and Quartz. Data loggers reflected a rise in water level (&lt;22 m bgl) corresponding to higher electrical conductivity (&gt;16 mS/Cm) during the cropping period in many locations, confirming the impact of ROB in groundwater. The results were further supported by enriched signatures of <em>δ</em>¹⁸O (∼ +1.5‰) and <em>δ</em>²H (∼ +15‰). The saturation index of the minerals reflected that carbonate minerals (Calcite &gt; Dolomite) were saturated in the ROB relative to the groundwater. The vertical variation of mineral assemblages in the boreholes indicated gypsum precipitation in the capillary zone along with calcite and dolomite. The assemblage varies as the groundwater moves from the disposal site. The speciation of different compounds along the groundwater path indicated higher carbonate and sulfate species (CaCO₃ &gt; CaHCO₃&gt; CaSO₄ &gt; NaSO₄ &gt; MgSO₄) near the disposal site, with variations along the flow direction. Considering the significant variation in temperature in the region (5 to 50 ℃), the water sample composition was modeled using PHREEQC, suggesting that the increase in temperature led to supersaturation of Epsomite and Gypsum compositions. The ROB was theoretically mixed with groundwater and product water in different proportions, and an optimum composition (10:90) for safe disposal was derived and tested fit for reuse in agriculture.</div></div>","PeriodicalId":12711,"journal":{"name":"Geoscience frontiers","volume":"15 6","pages":"Article 101929"},"PeriodicalIF":8.5,"publicationDate":"2024-09-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S1674987124001531/pdfft?md5=eeb0c4f759276a076fb0e36199c6d8ae&pid=1-s2.0-S1674987124001531-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142310459","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}