Yanran Huang, Man Luo, Fan Zhang, Taotao Cao, Ye Yu, Chenzhang Duan, Junjian Gao
Hydrothermal activities occurred in the Yangtze block, South China, and affected the process of black shale sedimentation in the early Cambrian. Their specific influences, such as the sources, sedimentary environment, and mineralization, have not yet been revealed. Fortunately, the influences are explained through the geochemistry comparison of different wells FY1, XJ1, HY1, and XA1 in northwestern Hunan. The outcomes of the tectonic setting, distinguishable by element indicators, are disorganized. This is caused by the variable element composition, sedimentary recirculation of material source, and hydrothermal materials. FY1, the closest well to Zhangjiajie where Ni–Mo ores were formed by hydrothermal sedimentation, has more different features on the elemental geochemistry, but many indexes still indicate that it is normal sediments. XA1, which is far from the other wells and deposited in the deep-water basin, has significantly more differences in geochemical properties and shows more about normal marine deposition. XJ1 and HY1 are intermediate between them. Based on these wells, the hydrothermal contribution to the black shale sedimentation is not significant. However, some contents of trace and rare earth elements change widely because hydrothermal materials can diffuse and deposit over long distances. The concentration of Ag, As, Ba, Mo, Ba, U, and V generally has dozens of times higher than that of Upper Continental Crust. The early Cambrian environment was primarily anoxic/euxinic with enough sulfur, which is beneficial for enriching metal elements and organic matter. The sequence FY1, XJ1, HY1, and XA1 in turn has the same performance on the distance with Zhangjiajie, different intervals of suboxic environment and element enrichment, and hydrothermal-fluid-addition Ni abundance. Therefore, hydrothermal processes indeed provide materials for element enrichment and support the reducing environment, but the impact of hydrothermal activity decreases on the plane.
{"title":"Element geochemical differences in lower Cambrian black shales with hydrothermal sedimentation in the Yangtze block, South China","authors":"Yanran Huang, Man Luo, Fan Zhang, Taotao Cao, Ye Yu, Chenzhang Duan, Junjian Gao","doi":"10.1515/geo-2022-0614","DOIUrl":"https://doi.org/10.1515/geo-2022-0614","url":null,"abstract":"Hydrothermal activities occurred in the Yangtze block, South China, and affected the process of black shale sedimentation in the early Cambrian. Their specific influences, such as the sources, sedimentary environment, and mineralization, have not yet been revealed. Fortunately, the influences are explained through the geochemistry comparison of different wells FY1, XJ1, HY1, and XA1 in northwestern Hunan. The outcomes of the tectonic setting, distinguishable by element indicators, are disorganized. This is caused by the variable element composition, sedimentary recirculation of material source, and hydrothermal materials. FY1, the closest well to Zhangjiajie where Ni–Mo ores were formed by hydrothermal sedimentation, has more different features on the elemental geochemistry, but many indexes still indicate that it is normal sediments. XA1, which is far from the other wells and deposited in the deep-water basin, has significantly more differences in geochemical properties and shows more about normal marine deposition. XJ1 and HY1 are intermediate between them. Based on these wells, the hydrothermal contribution to the black shale sedimentation is not significant. However, some contents of trace and rare earth elements change widely because hydrothermal materials can diffuse and deposit over long distances. The concentration of Ag, As, Ba, Mo, Ba, U, and V generally has dozens of times higher than that of Upper Continental Crust. The early Cambrian environment was primarily anoxic/euxinic with enough sulfur, which is beneficial for enriching metal elements and organic matter. The sequence FY1, XJ1, HY1, and XA1 in turn has the same performance on the distance with Zhangjiajie, different intervals of suboxic environment and element enrichment, and hydrothermal-fluid-addition Ni abundance. Therefore, hydrothermal processes indeed provide materials for element enrichment and support the reducing environment, but the impact of hydrothermal activity decreases on the plane.","PeriodicalId":48712,"journal":{"name":"Open Geosciences","volume":"26 1","pages":""},"PeriodicalIF":2.0,"publicationDate":"2024-03-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140166419","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Erteng Wang, Xinwei Zhai, Yaoshen Huang, Chengze Li, Ruihuan Su, Lei Wu, Gaorui Song, Zhiang Guo, Wanfeng Chen, Jinrong Wang
Late Paleozoic plutons are widely distributed in the Alxa region, southernmost Central Asian Orogenic Belt, and provided an important clue in constraint for the closing time of the Paleo-Asian Ocean (PAO). In this article, we present new zircon U-Pb ages and whole-rock geochemical data from the Permian Huoersen and Zongnaishan plutons in the southern Alxa region. The Huoersen gabbro (ca. 285 Ma) is enriched in large-ion lithophile elements and depleted in high-field strength elements, similar to the features of continental marginal arc. They were most likely generated by partial melting of depleted mantle that was modified by subduction metasomatic fluids. The Zongnaishan granites (ca. 267 Ma) show characteristics of I-type granites and were generated in a syn-collision setting. The Huoersen granites (ca. 259 Ma) are peralkaline and have positive ƐNd(t) (+1.2 to +1.5) values, exhibiting A2-subtype granites affinities. They were formed by melting of lower crust in post-collision extension setting. Based on geodynamic mechanism, a three-stage evolution model is delineated: subduction, syn-collision to post-collisional extension for oceanic branch of the PAO during the Permian. In general, the rock assemblages indicate a tectonic switch from subduction to post-collision extension regimes and the final closure of the PAO.
晚古生代柱岩广泛分布于中亚造山带最南端的阿拉善地区，为制约古亚洲洋（PAO）的关闭时间提供了重要线索。本文介绍了阿拉善地区南部二叠纪霍尔森和宗乃山岩柱的新锆石U-Pb年龄和全岩地球化学数据。霍尔森辉长岩（约 285 Ma）富含大离子亲岩元素，高场强元素贫乏，与大陆边缘弧的特征类似。它们很可能是由贫化地幔经俯冲变质流体部分熔融而生成的。宗拿山花岗岩（约 267 Ma）显示出 I 型花岗岩的特征，是在同步碰撞环境中生成的。霍尔森花岗岩（约259 Ma）呈围碱性，具有正的Ɛ Nd(t)（+1.2至+1.5）值，表现出A2亚型花岗岩的亲和性。它们是由碰撞后延伸环境中的下地壳熔融形成的。根据地球动力学机制，划分了一个三阶段演化模型：二叠纪 PAO 大洋分支的俯冲、同步碰撞到碰撞后延伸。总体而言，岩石组合显示了从俯冲延伸到碰撞后延伸的构造转换，以及 PAO 的最终关闭。
{"title":"Permian tectonic switch of the southern Central Asian Orogenic Belt: Constraints from magmatism in the southern Alxa region, NW China","authors":"Erteng Wang, Xinwei Zhai, Yaoshen Huang, Chengze Li, Ruihuan Su, Lei Wu, Gaorui Song, Zhiang Guo, Wanfeng Chen, Jinrong Wang","doi":"10.1515/geo-2022-0618","DOIUrl":"https://doi.org/10.1515/geo-2022-0618","url":null,"abstract":"Late Paleozoic plutons are widely distributed in the Alxa region, southernmost Central Asian Orogenic Belt, and provided an important clue in constraint for the closing time of the Paleo-Asian Ocean (PAO). In this article, we present new zircon U-Pb ages and whole-rock geochemical data from the Permian Huoersen and Zongnaishan plutons in the southern Alxa region. The Huoersen gabbro (ca. 285 Ma) is enriched in large-ion lithophile elements and depleted in high-field strength elements, similar to the features of continental marginal arc. They were most likely generated by partial melting of depleted mantle that was modified by subduction metasomatic fluids. The Zongnaishan granites (ca. 267 Ma) show characteristics of I-type granites and were generated in a syn-collision setting. The Huoersen granites (ca. 259 Ma) are peralkaline and have positive <jats:italic>Ɛ</jats:italic> <jats:sub>Nd</jats:sub>(<jats:italic>t</jats:italic>) (+1.2 to +1.5) values, exhibiting A<jats:sub>2</jats:sub>-subtype granites affinities. They were formed by melting of lower crust in post-collision extension setting. Based on geodynamic mechanism, a three-stage evolution model is delineated: subduction, syn-collision to post-collisional extension for oceanic branch of the PAO during the Permian. In general, the rock assemblages indicate a tectonic switch from subduction to post-collision extension regimes and the final closure of the PAO.","PeriodicalId":48712,"journal":{"name":"Open Geosciences","volume":"50 1","pages":""},"PeriodicalIF":2.0,"publicationDate":"2024-03-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140154503","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Caiyuan Dong, Wei Yang, Jun Li, Dejiang Li, Xueqiong Wu, Weidong Miao, Haihua Zhu, Xilin Yang
The Ahe Formation in the Dibei Area is a key natural gas exploration formation in the northern structural belt. Based on geological data such as formation tests and physical properties, the tight reservoirs were determined using the empirical statistics method, distribution function method, oil-bearing occurrence method, and bound fluid saturation method reasonably. The lower limit of the oil-bearing physical properties of the layer was further analyzed for the differences between the methods. The pore-throat structure of tight sandstone was characterized by high-pressure mercury intrusion data, and the classification and evaluation standard of tight sandstone in the Ahe Formation in the Dibei Area was established combining fractal theory and physical property data. The results show that the lower physical limit porosity of the tight reservoir of the Ahe Formation in the Dibei Area is 2.4%, and the lower permeability limit is 0.021 × 10−3 μm2. According to the fractal dimension characteristics of the mercury injection curve, the different structural characteristics of four types of pores (fracture, macropore, mesopore, and small pore) can be divided with the boundary values are 3,000, 1,000, and 100 nm; the tight reservoir of the Ahe Formation in Dibei Area can be classified into four categories: (a) type I reservoir (Ф > 7%), mainly composed of fracture and macropore; (b) type II reservoir (4% < Ф < 7%), mainly made up of macropore and mesopore; (c) type III reservoir (2% < Ф < 4%), mainly formed by mesopore; and (d) type IV reservoir (Ф < 2%) dominated by small pore, followed by mesopore.
{"title":"Lower limits of physical properties and classification evaluation criteria of the tight reservoir in the Ahe Formation in the Dibei Area of the Kuqa depression","authors":"Caiyuan Dong, Wei Yang, Jun Li, Dejiang Li, Xueqiong Wu, Weidong Miao, Haihua Zhu, Xilin Yang","doi":"10.1515/geo-2022-0572","DOIUrl":"https://doi.org/10.1515/geo-2022-0572","url":null,"abstract":"The Ahe Formation in the Dibei Area is a key natural gas exploration formation in the northern structural belt. Based on geological data such as formation tests and physical properties, the tight reservoirs were determined using the empirical statistics method, distribution function method, oil-bearing occurrence method, and bound fluid saturation method reasonably. The lower limit of the oil-bearing physical properties of the layer was further analyzed for the differences between the methods. The pore-throat structure of tight sandstone was characterized by high-pressure mercury intrusion data, and the classification and evaluation standard of tight sandstone in the Ahe Formation in the Dibei Area was established combining fractal theory and physical property data. The results show that the lower physical limit porosity of the tight reservoir of the Ahe Formation in the Dibei Area is 2.4%, and the lower permeability limit is 0.021 × 10<jats:sup>−3</jats:sup> μm<jats:sup>2</jats:sup>. According to the fractal dimension characteristics of the mercury injection curve, the different structural characteristics of four types of pores (fracture, macropore, mesopore, and small pore) can be divided with the boundary values are 3,000, 1,000, and 100 nm; the tight reservoir of the Ahe Formation in Dibei Area can be classified into four categories: (a) type I reservoir (<jats:italic>Ф</jats:italic> > 7%), mainly composed of fracture and macropore; (b) type II reservoir (4% < <jats:italic>Ф</jats:italic> < 7%), mainly made up of macropore and mesopore; (c) type III reservoir (2% < <jats:italic>Ф</jats:italic> < 4%), mainly formed by mesopore; and (d) type IV reservoir (<jats:italic>Ф</jats:italic> < 2%) dominated by small pore, followed by mesopore.","PeriodicalId":48712,"journal":{"name":"Open Geosciences","volume":"1 1","pages":""},"PeriodicalIF":2.0,"publicationDate":"2024-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140154383","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
It is necessary to evaluate the construction effect of viaducts and identify the viaducts that play a key role in road networks. Based on the node deletion method, this article proposes a method to identify the importance of viaducts in road networks. After applying this method to simulate the importance of viaducts in the highway networks in Yunnan and Guizhou Provinces from 2001 to 2020, the results show the following: (1) The viaducts with high importance were mainly built in 2002, 2009, 2015, and 2016. They are mainly distributed on expressways such as the HUKUN Expressway, HANGRUI Expressway, and YINBAI Expressway. Among the viaducts, the Mengzhai Bridge and Beipanjiang Bridge Hukun are the most important. (2) The importance of viaducts will increase, decrease, or increase first and then decrease. Among the years studied, 2012 and 2016 are important time nodes for change. The trend of changes is affected by the construction of highways and viaducts in other locations. In this road network, there are strong coupling relationships between nodes. (3) The importance of some viaducts is not prominent in the whole region, but that does not mean their construction value is low. They may have a high connectivity effect on specific regions from a local perspective.
{"title":"Evaluation of Viaducts’ contribution to road network accessibility in the Yunnan–Guizhou area based on the node deletion method","authors":"Zichen Wang, Changxiu Cheng, Lanlan Guo, Shan Liu","doi":"10.1515/geo-2022-0598","DOIUrl":"https://doi.org/10.1515/geo-2022-0598","url":null,"abstract":"It is necessary to evaluate the construction effect of viaducts and identify the viaducts that play a key role in road networks. Based on the node deletion method, this article proposes a method to identify the importance of viaducts in road networks. After applying this method to simulate the importance of viaducts in the highway networks in Yunnan and Guizhou Provinces from 2001 to 2020, the results show the following: (1) The viaducts with high importance were mainly built in 2002, 2009, 2015, and 2016. They are mainly distributed on expressways such as the HUKUN Expressway, HANGRUI Expressway, and YINBAI Expressway. Among the viaducts, the Mengzhai Bridge and Beipanjiang Bridge Hukun are the most important. (2) The importance of viaducts will increase, decrease, or increase first and then decrease. Among the years studied, 2012 and 2016 are important time nodes for change. The trend of changes is affected by the construction of highways and viaducts in other locations. In this road network, there are strong coupling relationships between nodes. (3) The importance of some viaducts is not prominent in the whole region, but that does not mean their construction value is low. They may have a high connectivity effect on specific regions from a local perspective.","PeriodicalId":48712,"journal":{"name":"Open Geosciences","volume":"17 1","pages":""},"PeriodicalIF":2.0,"publicationDate":"2024-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140154520","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Since the early 1980s, several regions of Morocco have experienced alternating series of wet and dry periods related to climate change, with significant consequences for the country’s economy. This study aims to map flood hazards by using a hydraulic modeling approach, with a specific focus on the Oued (river) Zaouiat Sidi Hamza passing through Zaouiat Sidi Hamza township belonging to the High Ziz watershed (province of Midelt, region of Drâa-Tafilalet, Morocco). Hydraulic modeling and flood simulation were carried out followed by mapping of the flood hazard. The Oued Zaouiat Sidi Hamza River can cause torrential flooding issues, particularly during periods of heavy storms, impacting agricultural land and certain buildings on both river banks. All the cultivated areas developed alongside the river are at risk of flooding. Moreover, undermining and erosion of the river’s banks lead to rising high-water levels and flooding agricultural terraces. The use of geographic information systems and hydraulic modeling tools is essential to gain a deeper understanding of this situation. Also, the mapping of lineaments and fractures in the study area, carried out by satellite image processing, helped to quantify the directional influence of these lineaments on the flow of the hydrographic network, on the orientation of the circulation of surface water, and on the storage of groundwater. According to this study, the most vulnerable areas to flooding and erosion are those that receive the most water in the basin and have steep slopes. Decision-makers can use the results to produce development plans tailored to combat these risks and raise awareness among the population concerned, improving water resource evaluation and forecasting, as well as improving agricultural production.
自 20 世纪 80 年代初以来，摩洛哥的一些地区经历了一系列与气候变化有关的干湿交替期，对国家经济造成了重大影响。本研究旨在利用水力模型方法绘制洪水危害图，重点关注穿过 Zaouiat Sidi Hamza 镇的 Zaouiat Sidi Hamza Oued（河），该镇属于 High Ziz 流域（摩洛哥 Midelt 省 Drâa-Tafilalet 地区）。在进行了水力模型和洪水模拟之后，绘制了洪水危害图。Oued Zaouiat Sidi Hamza 河会引发暴雨洪水问题，尤其是在暴风雨期间，对河岸两侧的农田和某些建筑物造成影响。沿河开发的所有耕地都有被洪水淹没的危险。此外，河岸的破坏和侵蚀会导致高水位上升，淹没农田梯田。使用地理信息系统和水力模型工具对深入了解这一情况至关重要。此外，通过卫星图像处理绘制的研究区域线状地形和断裂图，有助于量化这些线状地形对水文网络流向、地表水循环方向和地下水储存的定向影响。根据这项研究，最易受洪水和侵蚀影响的地区是那些流域内受水量最大、坡度较陡的地区。决策者可利用研究结果制定有针对性的发展计划，以应对这些风险，并提高相关人口的认识，改善水资源评估和预测，提高农业生产。
{"title":"Flood risk assessment, a case study in an arid environment of Southeast Morocco","authors":"Khadija Diani, Mohamed Hafedh Hamza, Hicham Elbelrhiti, Ilias Kacimi, Fatima Zahra Faqihi, Ali Torabi Haghighi, Mohamed El Amrani, Youssef Hahou, Lhoussaine Masmoudi, Ousaid Lahcen, Fahad Alshehri, Mohamed Elhag","doi":"10.1515/geo-2022-0607","DOIUrl":"https://doi.org/10.1515/geo-2022-0607","url":null,"abstract":"Since the early 1980s, several regions of Morocco have experienced alternating series of wet and dry periods related to climate change, with significant consequences for the country’s economy. This study aims to map flood hazards by using a hydraulic modeling approach, with a specific focus on the Oued (river) Zaouiat Sidi Hamza passing through Zaouiat Sidi Hamza township belonging to the High Ziz watershed (province of Midelt, region of Drâa-Tafilalet, Morocco). Hydraulic modeling and flood simulation were carried out followed by mapping of the flood hazard. The Oued Zaouiat Sidi Hamza River can cause torrential flooding issues, particularly during periods of heavy storms, impacting agricultural land and certain buildings on both river banks. All the cultivated areas developed alongside the river are at risk of flooding. Moreover, undermining and erosion of the river’s banks lead to rising high-water levels and flooding agricultural terraces. The use of geographic information systems and hydraulic modeling tools is essential to gain a deeper understanding of this situation. Also, the mapping of lineaments and fractures in the study area, carried out by satellite image processing, helped to quantify the directional influence of these lineaments on the flow of the hydrographic network, on the orientation of the circulation of surface water, and on the storage of groundwater. According to this study, the most vulnerable areas to flooding and erosion are those that receive the most water in the basin and have steep slopes. Decision-makers can use the results to produce development plans tailored to combat these risks and raise awareness among the population concerned, improving water resource evaluation and forecasting, as well as improving agricultural production.","PeriodicalId":48712,"journal":{"name":"Open Geosciences","volume":"30 1","pages":""},"PeriodicalIF":2.0,"publicationDate":"2024-03-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140154500","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This study aims to use attapulgite (ATT) and cement to modify loess as the lining material of landfills in loess areas and to exert the adsorption property of modified loess to ensure seepage prevention. It provides a safe, efficient, low-cost anti-seepage material for constructing a landfill in a loess area. For ATT-modified loess, when the content of ATT is less than 10%, the decrease rate of permeability coefficient is obvious, and when the content is more than 10%, the decrease rate becomes slow. After adding 5% cement on this basis, the permeability coefficient of ATT cement-modified loess is 8 × 10−8 cm/s, which meets the standard requirements (≤10−7 cm/s). The results show that the adsorption of Cu and Pb ions on ATT cement-modified loess is higher than that on pure loess. Cu and Pb ions’ adsorption rates are 99.2 and 98.5% in a single solution. In the mixed solution, the adsorption rates of copper and lead ions were 97.5 and 98.2%, respectively. Therefore, the study obtained the ratio of modified loess (85% loess + 10% ATT + 5% cement) that can not only meet the seepage prevention requirements of the landfill but also can adsorb heavy metal ions in the leachate, providing security for the landfill.
本研究旨在利用凹凸棒石（ATT）和水泥对黄土进行改性，作为黄土地区垃圾填埋场的衬垫材料，发挥改性黄土的吸附特性，确保防渗效果。它为在黄土地区建设垃圾填埋场提供了一种安全、高效、低成本的防渗材料。对于 ATT 改性黄土，当 ATT 含量小于 10%时，渗透系数下降速度明显，当 ATT 含量大于 10%时，下降速度变慢。在此基础上加入 5%水泥后，ATT 水泥改性黄土的渗透系数为 8×10-8 cm/s，达到标准要求（≤10-7 cm/s）。结果表明，Cu 和 Pb 离子在 ATT 水泥改性黄土上的吸附量高于纯黄土。在单一溶液中，铜离子和铅离子的吸附率分别为 99.2% 和 98.5%。在混合溶液中，铜离子和铅离子的吸附率分别为 97.5% 和 98.2%。因此，研究得到的改性黄土配比（85%黄土+10%ATT+5%水泥）既能满足垃圾填埋场的防渗要求，又能吸附渗滤液中的重金属离子，为垃圾填埋场提供了安全保障。
{"title":"Enhancing attapulgite and cement-modified loess for effective landfill lining: A study on seepage prevention and Cu/Pb ion adsorption","authors":"Zhengrui Zhang, Siti Jahara Matlan, Lili Zhang, Ahad Amini Pishro, Mojdeh Amini Pishro, Xian Gao, Nazaruddin Abdul Taha, Yuxin Zhou","doi":"10.1515/geo-2022-0617","DOIUrl":"https://doi.org/10.1515/geo-2022-0617","url":null,"abstract":"This study aims to use attapulgite (ATT) and cement to modify loess as the lining material of landfills in loess areas and to exert the adsorption property of modified loess to ensure seepage prevention. It provides a safe, efficient, low-cost anti-seepage material for constructing a landfill in a loess area. For ATT-modified loess, when the content of ATT is less than 10%, the decrease rate of permeability coefficient is obvious, and when the content is more than 10%, the decrease rate becomes slow. After adding 5% cement on this basis, the permeability coefficient of ATT cement-modified loess is 8 × 10<jats:sup>−8</jats:sup> cm/s, which meets the standard requirements (≤10<jats:sup>−7</jats:sup> cm/s). The results show that the adsorption of Cu and Pb ions on ATT cement-modified loess is higher than that on pure loess. Cu and Pb ions’ adsorption rates are 99.2 and 98.5% in a single solution. In the mixed solution, the adsorption rates of copper and lead ions were 97.5 and 98.2%, respectively. Therefore, the study obtained the ratio of modified loess (85% loess + 10% ATT + 5% cement) that can not only meet the seepage prevention requirements of the landfill but also can adsorb heavy metal ions in the leachate, providing security for the landfill.","PeriodicalId":48712,"journal":{"name":"Open Geosciences","volume":"114 1","pages":""},"PeriodicalIF":2.0,"publicationDate":"2024-03-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140129128","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The rapid growth of outdoor digital twin data sets and advancements in 3D data acquisition technology have sparked interest in improving segmentation performance using deep learning. This research aims to analyze and evaluate different sampling strategies and optimization techniques while exploring the intensity information of outdoor point cloud data. Two sampling strategies, random and stratified sampling, are employed to divide a limited data set. Additionally, the data set is divided into point cloud data with and without intensity. The PointNet++ model is used to segment the point cloud data into two classes, vegetation and structure. The results indicate that stratified sampling outperforms random sampling, yielding a considerable improvement in mean intersection over union scores of up to 10%. Interestingly, the inclusion of intensity information in the data set does not universally enhance performance. Although the use of intensity improves the performance of random sampling, it does not benefit stratified sampling. This research provides insights into the effectiveness of different sampling strategies for outdoor point cloud data segmentation. The findings can contribute to the development of optimized approaches to improving segmentation accuracy in outdoor digital twin applications using deep learning techniques.
{"title":"Improved deep learning segmentation of outdoor point clouds with different sampling strategies and using intensities","authors":"Harintaka Harintaka, Calvin Wijaya","doi":"10.1515/geo-2022-0611","DOIUrl":"https://doi.org/10.1515/geo-2022-0611","url":null,"abstract":"The rapid growth of outdoor digital twin data sets and advancements in 3D data acquisition technology have sparked interest in improving segmentation performance using deep learning. This research aims to analyze and evaluate different sampling strategies and optimization techniques while exploring the intensity information of outdoor point cloud data. Two sampling strategies, random and stratified sampling, are employed to divide a limited data set. Additionally, the data set is divided into point cloud data with and without intensity. The PointNet++ model is used to segment the point cloud data into two classes, vegetation and structure. The results indicate that stratified sampling outperforms random sampling, yielding a considerable improvement in mean intersection over union scores of up to 10%. Interestingly, the inclusion of intensity information in the data set does not universally enhance performance. Although the use of intensity improves the performance of random sampling, it does not benefit stratified sampling. This research provides insights into the effectiveness of different sampling strategies for outdoor point cloud data segmentation. The findings can contribute to the development of optimized approaches to improving segmentation accuracy in outdoor digital twin applications using deep learning techniques.","PeriodicalId":48712,"journal":{"name":"Open Geosciences","volume":"14 1","pages":""},"PeriodicalIF":2.0,"publicationDate":"2024-03-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140129127","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This article discusses the types and characteristics of platform margin belts on both sides of the Kaijiang-Liangping trough in the Sichuan Basin during the Late-Permian Changhsingian age combined with the seismic reflection characteristics. The results show that there are four types of platform margin belts on both sides of the Kaijiang-Liangping trough: (1) steep-slope, single-platform margin belts controlled by faults; (2) steep-slope, single-platform margin belts controlled by paleogeomorphology; (3) steep-slope, multiple-platform margin belts controlled by paleogeomorphology; and (4) gentle-slope, multiple-platform margin belts controlled by paleogeomorphology. Reefs developed in the different types of platform margin belts exhibit different morphological characteristics and stacking patterns. Among all the reefs that developed in steep-slope, platform marginal belts are mainly characterized by aggradational accretion and different degrees of lateral migration in different directions. In contrast, the reefs developed in gentle-slope platform margin belts show distinctive characteristics of multiple bandings and lateral extension. Research suggests that the differences in the platform margin belts’ structure and reefs’ development rules are jointly controlled by a combination of syn-sedimentary fault activities, paleogeomorphology, and sea-level fluctuations. These results can be used to explore and predict reef reservoirs on carbonate platform margins.
{"title":"Platform margin belt structure and sedimentation characteristics of Changxing Formation reefs on both sides of the Kaijiang-Liangping trough, eastern Sichuan Basin, China","authors":"Mingtao Zuo, Jiangong Wang, Xiujian Sun, Zhonggui Hu, Yadong Bai, Wei Yang, Hongzhe Li","doi":"10.1515/geo-2022-0615","DOIUrl":"https://doi.org/10.1515/geo-2022-0615","url":null,"abstract":"This article discusses the types and characteristics of platform margin belts on both sides of the Kaijiang-Liangping trough in the Sichuan Basin during the Late-Permian Changhsingian age combined with the seismic reflection characteristics. The results show that there are four types of platform margin belts on both sides of the Kaijiang-Liangping trough: (1) steep-slope, single-platform margin belts controlled by faults; (2) steep-slope, single-platform margin belts controlled by paleogeomorphology; (3) steep-slope, multiple-platform margin belts controlled by paleogeomorphology; and (4) gentle-slope, multiple-platform margin belts controlled by paleogeomorphology. Reefs developed in the different types of platform margin belts exhibit different morphological characteristics and stacking patterns. Among all the reefs that developed in steep-slope, platform marginal belts are mainly characterized by aggradational accretion and different degrees of lateral migration in different directions. In contrast, the reefs developed in gentle-slope platform margin belts show distinctive characteristics of multiple bandings and lateral extension. Research suggests that the differences in the platform margin belts’ structure and reefs’ development rules are jointly controlled by a combination of syn-sedimentary fault activities, paleogeomorphology, and sea-level fluctuations. These results can be used to explore and predict reef reservoirs on carbonate platform margins.","PeriodicalId":48712,"journal":{"name":"Open Geosciences","volume":"45 1","pages":""},"PeriodicalIF":2.0,"publicationDate":"2024-03-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140129126","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
David L. de Castro, Francisco H. R. Bezerra, Josibel G. Oliveira Jr
The karstification of carbonate rocks creates 3D maze voids that are normally controlled by fracture networks and sedimentary bedding. The spatial distribution and density of karst systems are usually complex and difficult to predict, demanding multidisciplinary studies at different scales of investigation to determine the spatial distribution and density of karst features and their possible links with cave systems controlled by the regional structural setting. The present study integrates geophysical datasets (gravity, electrical resistivity tomography - ERT, and ground penetrating radar - GPR) with a digital elevation model to investigate a karst system in the Irecê basin, a semiarid region of Brazil. Morphostructural lineaments reveal a NNW-SSE- and E-W-oriented structural setting of the crystalline basement, which is imprinted on the internal basin architecture, and surface drainage network. Negative gravity anomalies and high-gradient gravity zones indicate the main karstic zone, where karst landforms are concentrated. In addition, 2.5D gravity modeling provides the internal basin geometry, demonstrating that the karst system has evolved in the thickest sector of the basin. ERT profiles delineate the underground passages that connect dolines at depth. Finally, GPR data image shallow subsurface ghost-rock karstification that spread out from the surface to depth and that took advantage of vertical fractures and slightly arched bedding planes. Our results point out the role of the fracture corridors in channelizing hydrodynamic energy at a sufficiently high level to create caves by the total removal of dissolved material, whereas in the surrounding areas under low hydrodynamic conditions, overall shallow ghost-rock karstification took place, creating residual weathered rocks (alterites).
{"title":"Integrated geophysical approach for detection and size-geometry characterization of a multiscale karst system in carbonate units, semiarid Brazil","authors":"David L. de Castro, Francisco H. R. Bezerra, Josibel G. Oliveira Jr","doi":"10.1515/geo-2022-0606","DOIUrl":"https://doi.org/10.1515/geo-2022-0606","url":null,"abstract":"The karstification of carbonate rocks creates 3D maze voids that are normally controlled by fracture networks and sedimentary bedding. The spatial distribution and density of karst systems are usually complex and difficult to predict, demanding multidisciplinary studies at different scales of investigation to determine the spatial distribution and density of karst features and their possible links with cave systems controlled by the regional structural setting. The present study integrates geophysical datasets (gravity, electrical resistivity tomography - ERT, and ground penetrating radar - GPR) with a digital elevation model to investigate a karst system in the Irecê basin, a semiarid region of Brazil. Morphostructural lineaments reveal a NNW-SSE- and E-W-oriented structural setting of the crystalline basement, which is imprinted on the internal basin architecture, and surface drainage network. Negative gravity anomalies and high-gradient gravity zones indicate the main karstic zone, where karst landforms are concentrated. In addition, 2.5D gravity modeling provides the internal basin geometry, demonstrating that the karst system has evolved in the thickest sector of the basin. ERT profiles delineate the underground passages that connect dolines at depth. Finally, GPR data image shallow subsurface ghost-rock karstification that spread out from the surface to depth and that took advantage of vertical fractures and slightly arched bedding planes. Our results point out the role of the fracture corridors in channelizing hydrodynamic energy at a sufficiently high level to create caves by the total removal of dissolved material, whereas in the surrounding areas under low hydrodynamic conditions, overall shallow ghost-rock karstification took place, creating residual weathered rocks (alterites).","PeriodicalId":48712,"journal":{"name":"Open Geosciences","volume":"66 1","pages":""},"PeriodicalIF":2.0,"publicationDate":"2024-03-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140075703","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A large set of Paleozoic volcaniclastic rocks is exposed in the northwestern margin of the Junggar Basin from the southern part of the Central Asian Orogenic Belt. The Carboniferous volcaniclastic strata in this area have been studied in depth, and an accurate chronostratigraphic framework of these strata has been established. However, there is a lack of sufficient geochronological data for the deposition times of the other Paleozoic volcaniclastic strata. In this study, zircon U–Pb dating of the Ordovician, Silurian, and Devonian volcaniclastic strata in the area reveals that the youngest age of the tuffite sample collected from the originally defined Ordovician strata is 398 ± 11 Ma, which represents the age of volcanic activity during the period of tuffite deposition. Based on this finding, the originally defined Ordovician strata are redefined as the Lower Devonian. The youngest ages of the silty tuff samples collected from the originally defined Silurian strata peak are 445–418 Ma, so its age is Upper Silurian. The youngest ages of the tuffaceous sandstone samples collected from the originally defined Devonian strata peak are 346–342 Ma, so these Devonian are redefined as the Early Carboniferous strata. Two Archean ages (2,501 ± 12 and 3,193 ± 8 Ma) were obtained in Silurian strata, thus confirming the existence of metamorphic rock basement in the provenance areas from which the sediments were derived.
{"title":"Zircon U–Pb ages of the Paleozoic volcaniclastic strata in the Junggar Basin, NW China","authors":"Fan Chun","doi":"10.1515/geo-2022-0529","DOIUrl":"https://doi.org/10.1515/geo-2022-0529","url":null,"abstract":"A large set of Paleozoic volcaniclastic rocks is exposed in the northwestern margin of the Junggar Basin from the southern part of the Central Asian Orogenic Belt. The Carboniferous volcaniclastic strata in this area have been studied in depth, and an accurate chronostratigraphic framework of these strata has been established. However, there is a lack of sufficient geochronological data for the deposition times of the other Paleozoic volcaniclastic strata. In this study, zircon U–Pb dating of the Ordovician, Silurian, and Devonian volcaniclastic strata in the area reveals that the youngest age of the tuffite sample collected from the originally defined Ordovician strata is 398 ± 11 Ma, which represents the age of volcanic activity during the period of tuffite deposition. Based on this finding, the originally defined Ordovician strata are redefined as the Lower Devonian. The youngest ages of the silty tuff samples collected from the originally defined Silurian strata peak are 445–418 Ma, so its age is Upper Silurian. The youngest ages of the tuffaceous sandstone samples collected from the originally defined Devonian strata peak are 346–342 Ma, so these Devonian are redefined as the Early Carboniferous strata. Two Archean ages (2,501 ± 12 and 3,193 ± 8 Ma) were obtained in Silurian strata, thus confirming the existence of metamorphic rock basement in the provenance areas from which the sediments were derived.","PeriodicalId":48712,"journal":{"name":"Open Geosciences","volume":"270 1","pages":""},"PeriodicalIF":2.0,"publicationDate":"2024-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140044272","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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