Pub Date : 2024-11-17DOI: 10.1016/j.gsf.2024.101967
Yitong Zhang , Jiaqi Chen , Jiansheng Chen , Wang Wang
The Ordos Basin, located in arid and semi-arid region of China, is famous for its abundant groundwater resources and artesian features. The source of groundwater recharge, whether from local precipitation or external sources, has been debated. This study aims to elucidate the groundwater circulation mechanism in the Ordos Basin through scientific expedition, environmental isotope method, and hydrological drilling exploration, providing valuable insights for other artesian basins. Comprehensive analysis indicates that groundwater in the Ordos Basin is recharged by modern precipitation, primarily from high-elevation areas outside the basin. Deep groundwater from these external sources ascends to the aquifer through basement fault zones. Evidence from hydrogen and oxygen isotopes, hydraulic gradients, and water quantities suggests that the Tibetan Plateau is the most potential recharge source. Based on the distribution of Cenozoic basalt and data from seismic observation wells, we propose that leakage water from the Tibetan Plateau rift valley is transported to the Ordos Basin through fast channels, possibly lava tubes, and then upwelling through basement fault zones. This work provides a new perspective on the mechanism of inter-basin groundwater circulation.
{"title":"Inter-basin groundwater flow in the Ordos Basin: Evidence of environmental isotope and hydrological investigations","authors":"Yitong Zhang , Jiaqi Chen , Jiansheng Chen , Wang Wang","doi":"10.1016/j.gsf.2024.101967","DOIUrl":"10.1016/j.gsf.2024.101967","url":null,"abstract":"<div><div>The Ordos Basin, located in arid and semi-arid region of China, is famous for its abundant groundwater resources and artesian features. The source of groundwater recharge, whether from local precipitation or external sources, has been debated. This study aims to elucidate the groundwater circulation mechanism in the Ordos Basin through scientific expedition, environmental isotope method, and hydrological drilling exploration, providing valuable insights for other artesian basins. Comprehensive analysis indicates that groundwater in the Ordos Basin is recharged by modern precipitation, primarily from high-elevation areas outside the basin. Deep groundwater from these external sources ascends to the aquifer through basement fault zones. Evidence from hydrogen and oxygen isotopes, hydraulic gradients, and water quantities suggests that the Tibetan Plateau is the most potential recharge source. Based on the distribution of Cenozoic basalt and data from seismic observation wells, we propose that leakage water from the Tibetan Plateau rift valley is transported to the Ordos Basin through fast channels, possibly lava tubes, and then upwelling through basement fault zones. This work provides a new perspective on the mechanism of inter-basin groundwater circulation.</div></div>","PeriodicalId":12711,"journal":{"name":"Geoscience frontiers","volume":"16 1","pages":"Article 101967"},"PeriodicalIF":8.5,"publicationDate":"2024-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142746989","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}
The gold-bearing arsenian pyrite in Carlin-type gold deposits typically grows around the gold/arsenic-poor pyrite core, forming core–rim textured pyrite. However, the causes of rim pyrite precipitation around the early-formed core pyrite and the growth mechanisms of the rim pyrite remain unclear. Here, we combined scanning electron microscopy, electron probe micro-analysis, and nanoscale secondary ion mass spectrometry to investigate the textural and chemical characteristics of core–rim textured pyrite from the giant Shuiyindong and Lannigou gold deposits. Furthermore, we used electron backscattered diffraction and transmission electron microscopy to characterize their crystallographic structure. The results indicated that core–rim textured pyrite is the dominant pyrite type in the ore. This type of pyrite is characterized by the sharp core–rim interfaces, euhedral-subhedral morphology, and oscillating zoning. The gold/arsenic-rich rim and gold/arsenic-poor core formed during the main-ore and pre-ore stages, respectively. Crystallographically, the rim showed that a crystallographic orientation is similar to that of the core along the (0 1 0) crystal facet, indicating that the core pyrite serves as a template for the epitaxial growth of rim pyrite. Textural and chemical features indicate that the epitaxy occurs in the process of direct precipitation of main-ore pyrite over the pre-ore pyrite. As Carlin ore fluids dissolve the iron-bearing carbonates, iron concentrations in the fluids increase, thereby creating a supersaturation environment suitable for the nucleation of main-ore pyrite. Because the minimal lattice misfit would minimize the surface free energy and the (0 1 0) facet of pyrite has a lower surface energy than other facets, the nucleated pyrite would readily grow along the (0 1 0) facet of preexisting pyrite via epitaxy. Our findings highlight that the widespread preexisting pyrite facilitates late-stage pyrite precipitation. For Carlin-type gold deposits, the pre-ore pyrite is essential owing to its promoting the precipitation of gold-bearing pyrite.
{"title":"Consistent crystal orientation of core and rim pyrites indicates an epitaxial growth of rim in Carlin-type gold deposits","authors":"Jingdan Xiao , Zhuojun Xie , Yong Xia , Phillip Gopon , Qinping Tan","doi":"10.1016/j.gsf.2024.101966","DOIUrl":"10.1016/j.gsf.2024.101966","url":null,"abstract":"<div><div>The gold-bearing arsenian pyrite in Carlin-type gold deposits typically grows around the gold/arsenic-poor pyrite core, forming core–rim textured pyrite. However, the causes of rim pyrite precipitation around the early-formed core pyrite and the growth mechanisms of the rim pyrite remain unclear. Here, we combined scanning electron microscopy, electron probe micro-analysis, and nanoscale secondary ion mass spectrometry to investigate the textural and chemical characteristics of core–rim textured pyrite from the giant Shuiyindong and Lannigou gold deposits. Furthermore, we used electron backscattered diffraction and transmission electron microscopy to characterize their crystallographic structure. The results indicated that core–rim textured pyrite is the dominant pyrite type in the ore. This type of pyrite is characterized by the sharp core–rim interfaces, euhedral-subhedral morphology, and oscillating zoning. The gold/arsenic-rich rim and gold/arsenic-poor core formed during the main-ore and pre-ore stages, respectively. Crystallographically, the rim showed that a crystallographic orientation is similar to that of the core along the (0<!--> <!-->1<!--> <!-->0) crystal facet, indicating that the core pyrite serves as a template for the epitaxial growth of rim pyrite. Textural and chemical features indicate that the epitaxy occurs in the process of direct precipitation of main-ore pyrite over the pre-ore pyrite. As Carlin ore fluids dissolve the iron-bearing carbonates, iron concentrations in the fluids increase, thereby creating a supersaturation environment suitable for the nucleation of main-ore pyrite. Because the minimal lattice misfit would minimize the surface free energy and the (0<!--> <!-->1<!--> <!-->0) facet of pyrite has a lower surface energy than other facets, the nucleated pyrite would readily grow along the (0<!--> <!-->1<!--> <!-->0) facet of preexisting pyrite via epitaxy. Our findings highlight that the widespread preexisting pyrite facilitates late-stage pyrite precipitation. For Carlin-type gold deposits, the pre-ore pyrite is essential owing to its promoting the precipitation of gold-bearing pyrite.</div></div>","PeriodicalId":12711,"journal":{"name":"Geoscience frontiers","volume":"16 1","pages":"Article 101966"},"PeriodicalIF":8.5,"publicationDate":"2024-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142746987","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 : 2024-11-09DOI: 10.1016/j.gsf.2024.101962
Yingcai Sun , Qiushi Zhou , Rui Wang , Madeleine C.S. Humphreys
Magmatic volatiles (H2O, F, Cl), especially water, are critical in the formation of porphyry copper deposit, for its significance as a carrier for metals. However, accurately quantifying the water contents of deep ore-forming magma remain a challenge. Here, we used apatite and forward modelling methods to reconstruct magmatic water evolution histories, with special concern on the control of initial magmatic H2O contents and water saturation threshold to porphyry mineralization. Samples investigated include granitoid rocks and apatite from highly copper-mineralized and barren localities. Generally, our research suggested that both ore-related and ore-barren magma systems are hydrous, the modeled magmatic water contents vary significantly among systems whether mineralized or not, and the major difference lies in the threshold of water saturation (6.0 wt.% for barren, and up to 10.0 wt.% for highly mineralized). Combined with whole rock geochemistry data (high K2O and Sr/Y contents) and modeling result (high modeled water thresholds), we think the ore-related magmas are stored at deeper depth with higher water solubility. In conclusion, we propose that the level of magmatic water saturation plays a crucial role in the formation of porphyry copper systems. Fertile magma has higher water solubility to which deeper storage depth is a critical contributing factor, and can get significantly water enriched upon saturation.
{"title":"Magmatic initial and saturated water thresholds determine copper endowments: Insights from apatite F-Cl-OH compositions","authors":"Yingcai Sun , Qiushi Zhou , Rui Wang , Madeleine C.S. Humphreys","doi":"10.1016/j.gsf.2024.101962","DOIUrl":"10.1016/j.gsf.2024.101962","url":null,"abstract":"<div><div>Magmatic volatiles (H<sub>2</sub>O, F, Cl), especially water, are critical in the formation of porphyry copper deposit, for its significance as a carrier for metals. However, accurately quantifying the water contents of deep ore-forming magma remain a challenge. Here, we used apatite and forward modelling methods to reconstruct magmatic water evolution histories, with special concern on the control of initial magmatic H<sub>2</sub>O contents and water saturation threshold to porphyry mineralization. Samples investigated include granitoid rocks and apatite from highly copper-mineralized and barren localities. Generally, our research suggested that both ore-related and ore-barren magma systems are hydrous, the modeled magmatic water contents vary significantly among systems whether mineralized or not, and the major difference lies in the threshold of water saturation (6.0 wt.% for barren, and up to 10.0 wt.% for highly mineralized). Combined with whole rock geochemistry data (high K<sub>2</sub>O and Sr/Y contents) and modeling result (high modeled water thresholds), we think the ore-related magmas are stored at deeper depth with higher water solubility. In conclusion, we propose that the level of magmatic water saturation plays a crucial role in the formation of porphyry copper systems. Fertile magma has higher water solubility to which deeper storage depth is a critical contributing factor, and can get significantly water enriched upon saturation.</div></div>","PeriodicalId":12711,"journal":{"name":"Geoscience frontiers","volume":"16 1","pages":"Article 101962"},"PeriodicalIF":8.5,"publicationDate":"2024-11-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142701739","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 : 2024-11-07DOI: 10.1016/j.gsf.2024.101961
Yanning Pan , Yunhua Liu , Zengqian Hou , Qiang Sun , Nianzhi Jiao , Guochen Dong , Jihua Liu , Gaoxue Yang , Huiting Zhang , Hailiang Jia , Hao Huang
Against the background of realizing the goal of “carbon peaking and carbon neutrality”, using basaltic rocks for carbon mineralization is one of the most promising approaches to reduce the rise in atmospheric CO2 concentrations. This study conducted a series of experiments to assess carbon mineralization in nine basalt samples from the main terrestrial basalt reservoirs in China within CO2-H2O/brine-rock systems at low temperatures (≤35 °C). The results indicate that the secondary carbonates formed in the CO2-H2O/brine-basalt system are predominantly calcite rather than Mg-carbonate minerals at low temperatures (≤35 °C). Hence, at low temperatures (≤35 °C), basalt rich in Ca-bearing minerals promotes the formation of stable carbonate minerals more effectively than basalt containing Mg-bearing minerals. Furthermore, under conditions of low temperatures (≤35 °C) and pressures of approximately 3 MPa, the results suggest that alkaline olivine basalt, with a higher content of Ca-minerals and typical alkaline minerals (nepheline and Na-sanidine), exhibits the highest pH value and the highest amount of calcite. Hence, the alkaline minerals, nepheline and Na-sanidine, serve as pH buffers to increase the pH and promote the precipitation of calcite within CO2-H2O– basalt systems at low temperatures (≤35 °C). Among the nine evaluated basalts, basalt from the Shandong Linqu-Changle volcanic basin exhibits the highest rate of carbon mineralization at low temperatures (≤35 °C). Hence, Cenozoic alkaline olivine basalt from Shandong Linqu-Changle volcanic basin is one of the most promising basalt reservoirs in China for future in- situ carbonation. As for ex- situ carbonation, compared with olivine, diopside or Ca-plagioclase may be more appropriate for increasing ocean negative emissions.
{"title":"Laboratory experiments of carbon mineralization potential of the main terrestrial basalt reservoirs in China","authors":"Yanning Pan , Yunhua Liu , Zengqian Hou , Qiang Sun , Nianzhi Jiao , Guochen Dong , Jihua Liu , Gaoxue Yang , Huiting Zhang , Hailiang Jia , Hao Huang","doi":"10.1016/j.gsf.2024.101961","DOIUrl":"10.1016/j.gsf.2024.101961","url":null,"abstract":"<div><div>Against the background of realizing the goal of “carbon peaking and carbon neutrality”, using basaltic rocks for carbon mineralization is one of the most promising approaches to reduce the rise in atmospheric CO<sub>2</sub> concentrations. This study conducted a series of experiments to assess carbon mineralization in nine basalt samples from the main terrestrial basalt reservoirs in China within CO<sub>2</sub>-H<sub>2</sub>O/brine-rock systems at low temperatures (≤35 °C). The results indicate that the secondary carbonates formed in the CO<sub>2</sub>-H<sub>2</sub>O/brine-basalt system are predominantly calcite rather than Mg-carbonate minerals at low temperatures (≤35 °C). Hence, at low temperatures (≤35 °C), basalt rich in Ca-bearing minerals promotes the formation of stable carbonate minerals more effectively than basalt containing Mg-bearing minerals. Furthermore, under conditions of low temperatures (≤35 °C) and pressures of approximately 3 MPa, the results suggest that alkaline olivine basalt, with a higher content of Ca-minerals and typical alkaline minerals (nepheline and Na-sanidine), exhibits the highest pH value and the highest amount of calcite. Hence, the alkaline minerals, nepheline and Na-sanidine, serve as pH buffers to increase the pH and promote the precipitation of calcite within CO<sub>2</sub>-H<sub>2</sub>O– basalt systems at low temperatures (≤35 °C). Among the nine evaluated basalts, basalt from the Shandong Linqu-Changle volcanic basin exhibits the highest rate of carbon mineralization at low temperatures (≤35 °C). Hence, Cenozoic alkaline olivine basalt from Shandong Linqu-Changle volcanic basin is one of the most promising basalt reservoirs in China for future in- situ carbonation. As for ex- situ carbonation, compared with olivine, diopside or Ca-plagioclase may be more appropriate for increasing ocean negative emissions.</div></div>","PeriodicalId":12711,"journal":{"name":"Geoscience frontiers","volume":"16 1","pages":"Article 101961"},"PeriodicalIF":8.5,"publicationDate":"2024-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142701093","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 : 2024-11-04DOI: 10.1016/j.gsf.2024.101957
Yingqi Zhang , Gong Xu , Chenchen Wang , Yaxin Zhao , Zheng Mu , Yunhao Fan , Changwei Jing
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.
{"title":"Detection of Earth’s free oscillation and analysis of the non-synchronous oscillation phenomenon of normal modes","authors":"Yingqi Zhang , Gong Xu , Chenchen Wang , Yaxin Zhao , Zheng Mu , Yunhao Fan , 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 <sub>0</sub>S<sub>2</sub> 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}
Flood is one of the most devastating natural hazards. Employing machine learning models to construct flood susceptibility maps has become a pivotal step for decision-makers in disaster prevention and management. Existing flood conditioning factors inadequately account for regional characteristics of flood in the depiction of topography, potentially leading to an overestimation of flood susceptibility in flat areas. Addressing this gap, this study proposes a novel flood conditioning factor, local convexity factor (LCF), to enhance the accuracy of flood susceptibility modeling. Initially, LCF is computed based on a standard normal Gaussian surface to highlight elevation variations in local terrain. Subsequently, LCF is applied to flood susceptibility modeling using seven machine learning models across four distinct basins. Comparative analysis is conducted between flood susceptibility maps with and without the application of LCF to evaluate its impact on flood susceptibility modeling. The results demonstrate that the proposed LCF can enhance the accuracy of flood susceptibility modeling to varying degrees, across the four basins investigated. The Fujiang basin exhibited the most substantial improvement, with its AUC improved from 0.861 to 0.886, Producer’s Agreement improved from 0.869 to 0.899, and Overall Agreement improved from 0.778 to 0.811. Comparation with hydrodynamic inundation maps shows that particularly in relatively flat terrain areas, flood susceptibility maps incorporating LCF offer more precise delineation between flood-prone and non-flood-prone zones. This research holds potential for widespread application in the prediction of flood susceptibility using machine learning models, providing a novel perspective for enhancing their accuracy.
{"title":"A novel flood conditioning factor based on topography for flood susceptibility modeling","authors":"Jun Liu, Xueqiang Zhao, Yangbo Chen, Huaizhang Sun, Yu Gu, Shichao Xu","doi":"10.1016/j.gsf.2024.101960","DOIUrl":"10.1016/j.gsf.2024.101960","url":null,"abstract":"<div><div>Flood is one of the most devastating natural hazards. Employing machine learning models to construct flood susceptibility maps has become a pivotal step for decision-makers in disaster prevention and management. Existing flood conditioning factors inadequately account for regional characteristics of flood in the depiction of topography, potentially leading to an overestimation of flood susceptibility in flat areas. Addressing this gap, this study proposes a novel flood conditioning factor, local convexity factor (LCF), to enhance the accuracy of flood susceptibility modeling. Initially, LCF is computed based on a standard normal Gaussian surface to highlight elevation variations in local terrain. Subsequently, LCF is applied to flood susceptibility modeling using seven machine learning models across four distinct basins. Comparative analysis is conducted between flood susceptibility maps with and without the application of LCF to evaluate its impact on flood susceptibility modeling. The results demonstrate that the proposed LCF can enhance the accuracy of flood susceptibility modeling to varying degrees, across the four basins investigated. The Fujiang basin exhibited the most substantial improvement, with its AUC improved from 0.861 to 0.886, Producer’s Agreement improved from 0.869 to 0.899, and Overall Agreement improved from 0.778 to 0.811. Comparation with hydrodynamic inundation maps shows that particularly in relatively flat terrain areas, flood susceptibility maps incorporating LCF offer more precise delineation between flood-prone and non-flood-prone zones. This research holds potential for widespread application in the prediction of flood susceptibility using machine learning models, providing a novel perspective for enhancing their accuracy.</div></div>","PeriodicalId":12711,"journal":{"name":"Geoscience frontiers","volume":"16 1","pages":"Article 101960"},"PeriodicalIF":8.5,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142747121","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 : 2024-11-01DOI: 10.1016/j.gsf.2024.101955
Xuanxue Mo
{"title":"Fifteen years of Geoscience Frontiers and moving forward","authors":"Xuanxue Mo","doi":"10.1016/j.gsf.2024.101955","DOIUrl":"10.1016/j.gsf.2024.101955","url":null,"abstract":"","PeriodicalId":12711,"journal":{"name":"Geoscience frontiers","volume":"15 6","pages":"Article 101955"},"PeriodicalIF":8.5,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142699371","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}
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.
{"title":"Analyzing failure mechanisms and predicting step-like displacement: Rainfall and RWL dynamics in lock-unlock landslides","authors":"Xuekun Xiang , Haijia Wen , Jiafeng Xiao , Xiongfeng Wang , Hongyue Yin , 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}
Pub Date : 2024-10-29DOI: 10.1016/j.gsf.2024.101956
Mustafa Tevfik Kartal , Shahriyar Mukhtarov , Dervis Kirikkaleli
Compatible with the increasing public interest on climate change, countries have taken measures to combat climate change and support environmental sustainability. Considering this fact, this study investigates whether environmental measures, proxied by the environmental policy stringency (EPS) index, are efficient in achieving sustainability of environment in G7 countries as the leading economies; uses multiple environmental sustainability indicators, and applies quantile methods from 1991/Q1 to through 2020/Q4. The results show that (i) EPS curbs carbon dioxide emissions in France and the United States across all quantiles. Also, it has a declining effect in Germany and Italy at lower quantiles and in Canada at lower and higher quantiles; (ii) EPS declines ecological footprint in United States across all quantiles, while it curbs in Canada and Germany at lower quantiles as well as in Italy and United Kingdom at higher quantiles; (iii) EPS stimulates load capacity factor in France, United Kingdom, and United States across all quantiles and in Canada at higher quantiles; (iv) causal effect of EPS on the environment varies throughout quantiles; (v) the robustness of the results by quantile regression method is verified. Overall, the results reveal that the effect of EPS on environmental sustainability differentiates across environmental indicators, countries, and quantiles. In ensuring environmental quality, EPS is completely helpful in the United States, fully inefficient in Japan, and has a mixed effect in remaining G7 countries.
{"title":"Achieving environmental quality through stringent environmental policies: Comparative evidence from G7 countries by multiple environmental indicators","authors":"Mustafa Tevfik Kartal , Shahriyar Mukhtarov , Dervis Kirikkaleli","doi":"10.1016/j.gsf.2024.101956","DOIUrl":"10.1016/j.gsf.2024.101956","url":null,"abstract":"<div><div>Compatible with the increasing public interest on climate change, countries have taken measures to combat climate change and support environmental sustainability. Considering this fact, this study investigates whether environmental measures, proxied by the environmental policy stringency (EPS) index, are efficient in achieving sustainability of environment in G7 countries as the leading economies; uses multiple environmental sustainability indicators, and applies quantile methods from 1991/Q1 to through 2020/Q4. The results show that (i) EPS curbs carbon dioxide emissions in France and the United States across all quantiles. Also, it has a declining effect in Germany and Italy at lower quantiles and in Canada at lower and higher quantiles; (ii) EPS declines ecological footprint in United States across all quantiles, while it curbs in Canada and Germany at lower quantiles as well as in Italy and United Kingdom at higher quantiles; (iii) EPS stimulates load capacity factor in France, United Kingdom, and United States across all quantiles and in Canada at higher quantiles; (iv) causal effect of EPS on the environment varies throughout quantiles; (v) the robustness of the results by quantile regression method is verified. Overall, the results reveal that the effect of EPS on environmental sustainability differentiates across environmental indicators, countries, and quantiles. In ensuring environmental quality, EPS is completely helpful in the United States, fully inefficient in Japan, and has a mixed effect in remaining G7 countries.</div></div>","PeriodicalId":12711,"journal":{"name":"Geoscience frontiers","volume":"16 1","pages":"Article 101956"},"PeriodicalIF":8.5,"publicationDate":"2024-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142701091","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}
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.
{"title":"Aerosol spatiotemporal dynamics, source analysis and influence mechanisms over typical drylands","authors":"Yunfei Zhang , Xiangyue Chen , Fengtao Zhao , Qianrou Xia , Hanchen Xing , 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}
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