Pub Date : 2024-10-03DOI: 10.1016/j.gsf.2024.101941
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 P–T 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 P–T 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.
{"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":"","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":null,"pages":null},"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}
Pub Date : 2024-10-01DOI: 10.1016/j.gsf.2024.101934
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.
{"title":"Paleogeographic significance of unknown hyperextended continental crust in South Atlantic conjugated margin","authors":"","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":null,"pages":null},"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}
Pub Date : 2024-09-24DOI: 10.1016/j.gsf.2024.101936
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 SPHY (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.
{"title":"Linking basin-scale hydrology with climatic parameters in western Himalaya: Application of satellite data, temperature index modelling and in-situ observations","authors":"","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 m<sup>3</sup>/s over 1950–2022, with maximum runoff in summer-monsoon months, peaking in July (182.69 m<sup>3</sup>/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 m<sup>3</sup>/s) to post-2000 (63.47 m<sup>3</sup>/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":null,"pages":null},"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}
Pub Date : 2024-09-16DOI: 10.1016/j.gsf.2024.101932
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&D (RR&D), energy efficiency R&D (EER&D) and renewable energy consumption in the four countries with the highest RR&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&D expenditures. (iii) ENERPU increases EER&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.
{"title":"Does energy policy uncertainty matter for renewable energy and energy efficiency technologies? An affordable and clean energy perspective","authors":"","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&D (RR&D), energy efficiency R&D (EER&D) and renewable energy consumption in the four countries with the highest RR&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&D expenditures. (iii) ENERPU increases EER&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":null,"pages":null},"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}
Pub Date : 2024-09-14DOI: 10.1016/j.gsf.2024.101929
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 (<22 m bgl) corresponding to higher electrical conductivity (>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 δ18O (∼ +1.5‰) and δ2H (∼ +15‰). The saturation index of the minerals reflected that carbonate minerals (Calcite > 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 > CaHCO3> CaSO4 > NaSO4 > 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.
{"title":"Evaluation of environmental geochemical signatures due to RO rejects on arid agricultural farms and tangible solutions","authors":"","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 (<22 m bgl) corresponding to higher electrical conductivity (>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><sup>18</sup>O (∼ +1.5‰) and <em>δ</em><sup>2</sup>H (∼ +15‰). The saturation index of the minerals reflected that carbonate minerals (Calcite > 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 (CaCO<sub>3</sub> > CaHCO<sub>3</sub>> CaSO<sub>4</sub> > NaSO<sub>4</sub> > MgSO<sub>4</sub>) 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":null,"pages":null},"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}
Pub Date : 2024-09-12DOI: 10.1016/j.gsf.2024.101925
Constraining the melting temperature of iron under Earth’s inner core conditions is crucial for understanding core dynamics and planetary evolution. Here, we develop a deep potential (DP) model for iron that explicitly incorporates electronic entropy contributions governing thermodynamics under Earth’s core conditions. Extensive benchmarking demonstrates the DP’s high fidelity across relevant iron phases and extreme pressure and temperature conditions. Through thermodynamic integration and direct solid–liquid coexistence simulations, the DP predicts melting temperatures for iron at the inner core boundary, consistent with previous ab initio results. This resolves the previous discrepancy of iron’s melting temperature at ICB between the DP model and ab initio calculation and suggests the crucial contribution of electronic entropy. Our work provides insights into machine learning melting behavior of iron under core conditions and provides the basis for future development of binary or ternary DP models for iron and other elements in the core.
确定地球内核条件下铁的熔化温度对于理解地核动力学和行星演化至关重要。在这里，我们为铁建立了一个深电位（DP）模型，该模型明确纳入了在地核条件下支配热力学的电子熵贡献。广泛的基准测试证明了 DP 在相关铁相和极端压力与温度条件下的高保真性。通过热力学整合和直接的固液共存模拟，DP 预测了铁在内核边界的熔化温度，与之前的 ab initio 结果一致。这解决了之前 DP 模型和 ab initio 计算在内核边界铁熔化温度上的差异，并表明电子熵的关键作用。我们的工作为铁在内核条件下的机器学习熔化行为提供了见解，并为今后开发铁和内核中其他元素的二元或三元 DP 模型奠定了基础。
{"title":"Melting temperature of iron under the Earth’s inner core condition from deep machine learning","authors":"","doi":"10.1016/j.gsf.2024.101925","DOIUrl":"10.1016/j.gsf.2024.101925","url":null,"abstract":"<div><p>Constraining the melting temperature of iron under Earth’s inner core conditions is crucial for understanding core dynamics and planetary evolution. Here, we develop a deep potential (DP) model for iron that explicitly incorporates electronic entropy contributions governing thermodynamics under Earth’s core conditions. Extensive benchmarking demonstrates the DP’s high fidelity across relevant iron phases and extreme pressure and temperature conditions. Through thermodynamic integration and direct solid–liquid coexistence simulations, the DP predicts melting temperatures for iron at the inner core boundary, consistent with previous <em>ab initio</em> results. This resolves the previous discrepancy of iron’s melting temperature at ICB between the DP model and <em>ab initio</em> calculation and suggests the crucial contribution of electronic entropy. Our work provides insights into machine learning melting behavior of iron under core conditions and provides the basis for future development of binary or ternary DP models for iron and other elements in the core.</p></div>","PeriodicalId":12711,"journal":{"name":"Geoscience frontiers","volume":null,"pages":null},"PeriodicalIF":8.5,"publicationDate":"2024-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S167498712400149X/pdfft?md5=f339d8310fb9c376123ddf74211961fa&pid=1-s2.0-S167498712400149X-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142256609","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}
Pub Date : 2024-09-11DOI: 10.1016/j.gsf.2024.101928
Since there is a scientific consensus that the energy sector has brought the planet to the tipping point of climate change, transitioning to sustainable energy sources is inevitable to halt foreseeable climatic adversities. This study looks at how promoting green taxation and sustainable energy transition affected the G7 nations’ goal of low-carbon development between 1994 and 2020. This study used Generalized Least Squares Random Effects Regression and Driscoll-Kraay Standard Errors-based Least Sqaures approaches for empirical analysis. The latter approach accounts for cross-sectional dependence, heteroscedasticity, and autocorrelation to provide robust empirical outcomes. The empirical results are as follows: Firstly, through lowering CO2 intensity and greenhouse gas emissions, the environmental tax revenues have enhanced the condition of the environment. The total tax revenues linked to the environment had a greater overall impact than the tax revenues related to the energy industry. Furthermore, compared to CO2 intensity, both of the environmental tax revenue factors contributed considerably more to greenhouse gas emissions. Second, the sustainable energy transition helped to lower greenhouse gas and CO2 intensity. Among covariates, international trade was supportive of low-carbon development, but industrialization and GDP per capita did the opposite. The panel bootstrap causality revealed a unidirectional causal connection from all independent variables, except foreign direct investment, to CO2 intensity and greenhouse gas emissions. These results demonstrated that the G7 nations’ environmental policies supported their commitment to achieving low-carbon development goals. In this respect, the G7 nations’ environmental emission reduction efforts benefited more from the overall environmental tax revenues. To secure the industrial emissions reduction for a future with net-zero carbon emissions, it is thus advised to continue using policies that price environmental emissions, such as the carbon taxation regulations. Additionally, plans for the sustainable energy transition that includes a quick rise in renewable energy sources in the overall energy mix are successful in lowering environmental emissions. For environmental sustainability and low-carbon development, it is thus advised to divert the taxation burden from renewable energy technologies to the fossil fuel industry to enhance the sustainable energy transition phenomenon for achieving Sustainable Development Goals (especially SDG-7 and SDG-13).
{"title":"Promoting green taxation and sustainable energy transition for low-carbon development","authors":"","doi":"10.1016/j.gsf.2024.101928","DOIUrl":"10.1016/j.gsf.2024.101928","url":null,"abstract":"<div><div>Since there is a scientific consensus that the energy sector has brought the planet to the tipping point of climate change, transitioning to sustainable energy sources is inevitable to halt foreseeable climatic adversities. This study looks at how promoting green taxation and sustainable energy transition affected the G7 nations’ goal of low-carbon development between 1994 and 2020. This study used Generalized Least Squares Random Effects Regression and Driscoll-Kraay Standard Errors-based Least Sqaures approaches for empirical analysis. The latter approach accounts for cross-sectional dependence, heteroscedasticity, and autocorrelation to provide robust empirical outcomes. The empirical results are as follows: Firstly, through lowering CO<sub>2</sub> intensity and greenhouse gas emissions, the environmental tax revenues have enhanced the condition of the environment. The total tax revenues linked to the environment had a greater overall impact than the tax revenues related to the energy industry. Furthermore, compared to CO<sub>2</sub> intensity, both of the environmental tax revenue factors contributed considerably more to greenhouse gas emissions. Second, the sustainable energy transition helped to lower greenhouse gas and CO<sub>2</sub> intensity. Among covariates, international trade was supportive of low-carbon development, but industrialization and GDP per capita did the opposite. The panel bootstrap causality revealed a unidirectional causal connection from all independent variables, except foreign direct investment, to CO<sub>2</sub> intensity and greenhouse gas emissions. These results demonstrated that the G7 nations’ environmental policies supported their commitment to achieving low-carbon development goals. In this respect, the G7 nations’ environmental emission reduction efforts benefited more from the overall environmental tax revenues. To secure the industrial emissions reduction for a future with net-zero carbon emissions, it is thus advised to continue using policies that price environmental emissions, such as the carbon taxation regulations. Additionally, plans for the sustainable energy transition that includes a quick rise in renewable energy sources in the overall energy mix are successful in lowering environmental emissions. For environmental sustainability and low-carbon development, it is thus advised to divert the taxation burden from renewable energy technologies to the fossil fuel industry to enhance the sustainable energy transition phenomenon for achieving Sustainable Development Goals (especially SDG-7 and SDG-13).</div></div>","PeriodicalId":12711,"journal":{"name":"Geoscience frontiers","volume":null,"pages":null},"PeriodicalIF":8.5,"publicationDate":"2024-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142446525","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}
Pub Date : 2024-09-10DOI: 10.1016/j.gsf.2024.101927
<div><p>In recent years, the characteristics and sources of fertile adakites has received considerable attention. As well, most recently the geodynamic environment of convergent margins subducting oceanic crust aiding arc formation, evolving to slab rollback, then slab break-off after collision (i.e. late- to post-collisional slab failure (arc-like magmatism) and transpression) has gained more recognition, although their relationship to each other has yet to be explored. The geochemical characteristics imply that adakites/adakite-like, in particular high-silica adakites (HSA), can form by partial melting of subducting hydrothermally altered oceanic crust in convergent plate boundary settings during the terminal stages of subduction, lithosphere thickening, and then failure (all late to post collisional), while the melting of the mantle wedge during subduction-related dehydration creates more typical calc-alkaline basalt-andesite-dacite-rhyolite series (ADR) to form intraoceanic island arc to intracontinental margin arc systems, before the collisional stage. HSAs are characterized by high-silica (SiO<sub>2</sub> > 67 wt.%), Al<sub>2</sub>O<sub>3</sub> > 15 wt.%, Sr > 300 ppm, Y<20 ppm, Yb < 1.8 ppm, and Nb ≤ 10 ppm, and MgO < 3 wt.%, with high Sr/Y (>50), and La/Yb (>10). Some specific geochemical features, such as high Mg# (ave 0.51), Ni (ave 924 ppm), and Cr (ave 36 ppm), in HSAs are typical, in contrast to calc-alkaline arcs, although both groups display similar but less pronounced negative anomalies of Nb, Ta, and Ti in primitive mantle-normalized trace element spider diagram profiles. These unique geochemical features are likely ascribed to the involvement of garnet, hornblende, and titanite either during partial melting of hydrous MORB-like oceanic crust with only minor assimilation and fractional crystallization (AFC) within the mantle and crustal during ascent in a transpressional collisional environment. Hypotheses for origin of HSA derivative from melting in convergent margins from young, hot oceanic plates subducting into the mantle is applicable to only some adakitic systems. The difference in geochemical characteristics of adakites compared to ADR, such as relative higher MgO, Cr, Cu, and Ni, are due to their slab source, as well as interaction of the slab-derived adakitic melts with overlying hot lithospheric mantle; altered oceanic slabs are also relatively rich in siderophile and other chalcophile elements, as well as sulfates and sulfides. HSA magmas related to slab failure have special geochemical properties, such as Sr/Y > 20, Nb/Y > 0.4, Ta/Yb > 0.3, La/Yb > 10, Gd/Yb > 2, and Sm/Yb > 2.5. Slightly higher Nb + Ta is due to high <em>T</em> melting of rutile. Varieties of Nb/Ta compared to silica are also significant in HSA as a result of slab failure (roll back to break-off). High <em>T</em>-<em>P</em> partial melting of the hydrothermally altered oceanic slab produces HSA with quite hig
{"title":"Formation of high-silica adakites and their relationship with slab break-off: Implications for generating fertile Cu-Au-Mo porphyry systems","authors":"","doi":"10.1016/j.gsf.2024.101927","DOIUrl":"10.1016/j.gsf.2024.101927","url":null,"abstract":"<div><p>In recent years, the characteristics and sources of fertile adakites has received considerable attention. As well, most recently the geodynamic environment of convergent margins subducting oceanic crust aiding arc formation, evolving to slab rollback, then slab break-off after collision (i.e. late- to post-collisional slab failure (arc-like magmatism) and transpression) has gained more recognition, although their relationship to each other has yet to be explored. The geochemical characteristics imply that adakites/adakite-like, in particular high-silica adakites (HSA), can form by partial melting of subducting hydrothermally altered oceanic crust in convergent plate boundary settings during the terminal stages of subduction, lithosphere thickening, and then failure (all late to post collisional), while the melting of the mantle wedge during subduction-related dehydration creates more typical calc-alkaline basalt-andesite-dacite-rhyolite series (ADR) to form intraoceanic island arc to intracontinental margin arc systems, before the collisional stage. HSAs are characterized by high-silica (SiO<sub>2</sub> > 67 wt.%), Al<sub>2</sub>O<sub>3</sub> > 15 wt.%, Sr > 300 ppm, Y<20 ppm, Yb < 1.8 ppm, and Nb ≤ 10 ppm, and MgO < 3 wt.%, with high Sr/Y (>50), and La/Yb (>10). Some specific geochemical features, such as high Mg# (ave 0.51), Ni (ave 924 ppm), and Cr (ave 36 ppm), in HSAs are typical, in contrast to calc-alkaline arcs, although both groups display similar but less pronounced negative anomalies of Nb, Ta, and Ti in primitive mantle-normalized trace element spider diagram profiles. These unique geochemical features are likely ascribed to the involvement of garnet, hornblende, and titanite either during partial melting of hydrous MORB-like oceanic crust with only minor assimilation and fractional crystallization (AFC) within the mantle and crustal during ascent in a transpressional collisional environment. Hypotheses for origin of HSA derivative from melting in convergent margins from young, hot oceanic plates subducting into the mantle is applicable to only some adakitic systems. The difference in geochemical characteristics of adakites compared to ADR, such as relative higher MgO, Cr, Cu, and Ni, are due to their slab source, as well as interaction of the slab-derived adakitic melts with overlying hot lithospheric mantle; altered oceanic slabs are also relatively rich in siderophile and other chalcophile elements, as well as sulfates and sulfides. HSA magmas related to slab failure have special geochemical properties, such as Sr/Y > 20, Nb/Y > 0.4, Ta/Yb > 0.3, La/Yb > 10, Gd/Yb > 2, and Sm/Yb > 2.5. Slightly higher Nb + Ta is due to high <em>T</em> melting of rutile. Varieties of Nb/Ta compared to silica are also significant in HSA as a result of slab failure (roll back to break-off). High <em>T</em>-<em>P</em> partial melting of the hydrothermally altered oceanic slab produces HSA with quite hig","PeriodicalId":12711,"journal":{"name":"Geoscience frontiers","volume":null,"pages":null},"PeriodicalIF":8.5,"publicationDate":"2024-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S1674987124001518/pdfft?md5=ba2bc6b1a17fb58b1e913047e8b1ce72&pid=1-s2.0-S1674987124001518-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142240591","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}
Pub Date : 2024-09-10DOI: 10.1016/j.gsf.2024.101924
Despite the growing concern regarding post-mineralization thermo-tectonic processes in recent years, the relative roles in exhuming and preserving ore deposits remain highly controversial. This study presents new apatite fission track and (U-Th)/He data from the Xishimen iron skarn deposit in the Handan-Xingtai district, central North China Craton. Apatite fission track dating yielded central ages ranging from 88 ± 18 Ma to 125 ± 9 Ma, with mean confined track lengths varying between 11.9 ± 0.4 μm and 13.3 ± 0.2 μm. Integrated apatite (U-Th)/He dating provided ages of 42.5 ± 0.8 Ma to 48.1 ± 3.3 Ma. Our new data, combined with previous zircon U-Pb and potassium-bearing mineral 40Ar/39Ar ages, revealed three cooling episodes: very rapid cooling (100–140 °C/Ma) at ca. 130–120 Ma, a protracted slow cooling period (0.2–0.4 °C/Ma) at ca. 120–50 Ma, and moderate cooling (0.8–1.0 °C/Ma) since ca. 50 Ma. The initial rapid cooling phase was primarily attributed to post-magmatic thermal equilibration following the shallow emplacement of the Xishimen deposit. The subsequent cooling phases were controlled by uplift and exhumation processes. Our thermal models indicate an estimated total unroofing thickness of < 3 km, which is shallower than the emplacement depth of the ore deposit (3–5 km). This suggests significant potential for mineral exploration. Furthermore, a comprehensive review of preservation mechanisms for various ore deposits underscores the significant role of tectonics in both exhuming and preserving ore bodies.
尽管近年来人们越来越关注成矿后的热构造过程，但对矿床出露和保存的相对作用仍存在很大争议。本研究提供了华北克拉通中部邯郸-邢台地区西石门铁矽卡岩矿床新的磷灰石裂变轨迹和（U-Th）/He数据。磷灰石裂变轨迹测年得出的中心年龄为88±18Ma至125±9Ma，平均封闭轨迹长度为11.9±0.4μm至13.3±0.2μm。磷灰石（U-Th）/He综合测年提供了 42.5 ± 0.8 Ma 至 48.1 ± 3.3 Ma 的年龄。我们的新数据与之前的锆石 U-Pb 和含钾矿物 40Ar/39Ar 年龄相结合，揭示了三个冷却过程：约 130-120 Ma 时的极速冷却（100-140 °C/Ma）、约 130-120 Ma 时的长期冷却（100-140 °C/Ma）、约 130-120 Ma 时的长期冷却（100-140 °C/Ma）。约 130-120 Ma 时的极快速冷却（100-140 °C/Ma），约 120-50 Ma 时的长期缓慢冷却（0.2-0.4 °C/Ma），以及中度冷却（0.2-0.4 °C/Ma）。120-50Ma，以及自约 50Ma 开始的中度冷却（0.8-1.0 °C/Ma）。从大约 50 Ma 开始的中度冷却（0.8-1.0 °C/Ma）。最初的快速冷却阶段主要归因于西石门沉积层浅部置入后的岩浆热平衡。随后的冷却阶段则由隆起和掘起过程控制。我们的热模型表明，估计的总揭露厚度为 3 千米，比矿床的堆积深度（3-5 千米）要浅。这表明这里具有巨大的矿产勘探潜力。此外，对各种矿床保存机制的全面审查强调了构造作用在矿体出露和保存方面的重要作用。
{"title":"Tectonic controls on ore deposit exhumation and preservation: A case study of the Handan-Xingtai iron-skarn district","authors":"","doi":"10.1016/j.gsf.2024.101924","DOIUrl":"10.1016/j.gsf.2024.101924","url":null,"abstract":"<div><p>Despite the growing concern regarding post-mineralization thermo-tectonic processes in recent years, the relative roles in exhuming and preserving ore deposits remain highly controversial. This study presents new apatite fission track and (U-Th)/He data from the Xishimen iron skarn deposit in the Handan-Xingtai district, central North China Craton. Apatite fission track dating yielded central ages ranging from 88 ± 18 Ma to 125 ± 9 Ma, with mean confined track lengths varying between 11.9 ± 0.4 μm and 13.3 ± 0.2 μm. Integrated apatite (U-Th)/He dating provided ages of 42.5 ± 0.8 Ma to 48.1 ± 3.3 Ma. Our new data, combined with previous zircon U-Pb and potassium-bearing mineral <sup>40</sup>Ar/<sup>39</sup>Ar ages, revealed three cooling episodes: very rapid cooling (100–140 °C/Ma) at ca. 130–120 Ma, a protracted slow cooling period (0.2–0.4 °C/Ma) at ca. 120–50 Ma, and moderate cooling (0.8–1.0 °C/Ma) since ca. 50 Ma. The initial rapid cooling phase was primarily attributed to post-magmatic thermal equilibration following the shallow emplacement of the Xishimen deposit. The subsequent cooling phases were controlled by uplift and exhumation processes. Our thermal models indicate an estimated total unroofing thickness of < 3 km, which is shallower than the emplacement depth of the ore deposit (3–5 km). This suggests significant potential for mineral exploration. Furthermore, a comprehensive review of preservation mechanisms for various ore deposits underscores the significant role of tectonics in both exhuming and preserving ore bodies.</p></div>","PeriodicalId":12711,"journal":{"name":"Geoscience frontiers","volume":null,"pages":null},"PeriodicalIF":8.5,"publicationDate":"2024-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S1674987124001488/pdfft?md5=40fe852d394f5c2affe439b4dbbc38c4&pid=1-s2.0-S1674987124001488-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142256607","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}
Pub Date : 2024-09-07DOI: 10.1016/j.gsf.2024.101926
Haibo Liu, Baohua Zhang, Hongzhan Fei, Lei Liu
Molecular hydrogen (H2) may be an important form of water in nominally anhydrous minerals in the Earth’s mantle and plays a critical role in mantle water cycle, but the transport properties of H2 remain unclear. Here, the diffusion of H2 in Fe-free olivine lattice is investigated at pressures of 1–13 GPa and temperatures of 1300–1900 K by first-principles molecular dynamics. The activation energy and activation volume for H2 diffusion in Fe-free olivine are determined to be 55 ± 8 kJ/mol and 3.6 ± 0.2 cm3/mol, respectively. H2 diffusion in Fe-free olivine is faster than H+ by 1–4 orders of magnitude and therefore it is more favorable for hydrogen transportation under upper mantle conditions. H2 can be carried to the mantle transition zone by subducting slabs without releasing to the surrounding mantle. The upper mantle may act as a lid, preventing the releasing of H2 produced in the deep mantle to the surface.
{"title":"A first-principles molecular dynamics study of molecular hydrogen diffusion in Fe-free olivine","authors":"Haibo Liu, Baohua Zhang, Hongzhan Fei, Lei Liu","doi":"10.1016/j.gsf.2024.101926","DOIUrl":"https://doi.org/10.1016/j.gsf.2024.101926","url":null,"abstract":"Molecular hydrogen (H<ce:inf loc=\"post\">2</ce:inf>) may be an important form of water in nominally anhydrous minerals in the Earth’s mantle and plays a critical role in mantle water cycle, but the transport properties of H<ce:inf loc=\"post\">2</ce:inf> remain unclear. Here, the diffusion of H<ce:inf loc=\"post\">2</ce:inf> in Fe-free olivine lattice is investigated at pressures of 1–13 GPa and temperatures of 1300–1900 K by first-principles molecular dynamics. The activation energy and activation volume for H<ce:inf loc=\"post\">2</ce:inf> diffusion in Fe-free olivine are determined to be 55 ± 8 kJ/mol and 3.6 ± 0.2 cm<ce:sup loc=\"post\">3</ce:sup>/mol, respectively. H<ce:inf loc=\"post\">2</ce:inf> diffusion in Fe-free olivine is faster than H<ce:sup loc=\"post\">+</ce:sup> by 1–4 orders of magnitude and therefore it is more favorable for hydrogen transportation under upper mantle conditions. H<ce:inf loc=\"post\">2</ce:inf> can be carried to the mantle transition zone by subducting slabs without releasing to the surrounding mantle. The upper mantle may act as a lid, preventing the releasing of H<ce:inf loc=\"post\">2</ce:inf> produced in the deep mantle to the surface.","PeriodicalId":12711,"journal":{"name":"Geoscience frontiers","volume":null,"pages":null},"PeriodicalIF":8.9,"publicationDate":"2024-09-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142256608","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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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