Open Geosciences最新文献_第7页

Element geochemical differences in lower Cambrian black shales with hydrothermal sedimentation in the Yangtze block, South China 下寒武统黑色页岩中的元素地球化学差异与华南扬子地块的热液沉积作用

IF 2 4区地球科学

Open Geosciences Pub Date : 2024-03-18 DOI: 10.1515/geo-2022-0614

Yanran Huang, Man Luo, Fan Zhang, Taotao Cao, Ye Yu, Chenzhang Duan, Junjian Gao

{"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}

引用次数: 0

Permian tectonic switch of the southern Central Asian Orogenic Belt: Constraints from magmatism in the southern Alxa region, NW China 中亚造山带南部二叠纪构造转换：中国西北部阿拉善地区南部岩浆活动的制约因素

IF 2 4区地球科学

Open Geosciences Pub Date : 2024-03-16 DOI: 10.1515/geo-2022-0618

Erteng Wang, Xinwei Zhai, Yaoshen Huang, Chengze Li, Ruihuan Su, Lei Wu, Gaorui Song, Zhiang Guo, Wanfeng Chen, Jinrong Wang

{"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 Ɛ Nd(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.","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}

引用次数: 0

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 库车凹陷迪北地区阿河地层致密储层物性下限及分类评价标准

IF 2 4区地球科学

Open Geosciences Pub Date : 2024-03-15 DOI: 10.1515/geo-2022-0572

Caiyuan Dong, Wei Yang, Jun Li, Dejiang Li, Xueqiong Wu, Weidong Miao, Haihua Zhu, Xilin Yang

{"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 × 10−3 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.","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}

引用次数: 0

Evaluation of Viaducts’ contribution to road network accessibility in the Yunnan–Guizhou area based on the node deletion method 基于节点删除法的云贵地区高架桥对路网通达性的贡献评价

IF 2 4区地球科学

Open Geosciences Pub Date : 2024-03-15 DOI: 10.1515/geo-2022-0598

Zichen Wang, Changxiu Cheng, Lanlan Guo, Shan Liu

{"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}

引用次数: 0

Flood risk assessment, a case study in an arid environment of Southeast Morocco 洪水风险评估，摩洛哥东南部干旱环境的案例研究

IF 2 4区地球科学

Open Geosciences Pub Date : 2024-03-14 DOI: 10.1515/geo-2022-0607

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

{"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}

引用次数: 0

Enhancing attapulgite and cement-modified loess for effective landfill lining: A study on seepage prevention and Cu/Pb ion adsorption 提高阿塔波利特和水泥改性黄土在垃圾填埋场衬砌中的有效性：防渗和铜/铅离子吸附研究

IF 2 4区地球科学

Open Geosciences Pub Date : 2024-03-13 DOI: 10.1515/geo-2022-0617

Zhengrui Zhang, Siti Jahara Matlan, Lili Zhang, Ahad Amini Pishro, Mojdeh Amini Pishro, Xian Gao, Nazaruddin Abdul Taha, Yuxin Zhou

{"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 × 10−8 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.","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}

引用次数: 0

Improved deep learning segmentation of outdoor point clouds with different sampling strategies and using intensities 利用不同的采样策略和强度改进户外点云的深度学习分割

IF 2 4区地球科学

Open Geosciences Pub Date : 2024-03-13 DOI: 10.1515/geo-2022-0611

Harintaka Harintaka, Calvin Wijaya

{"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}

引用次数: 0

Platform margin belt structure and sedimentation characteristics of Changxing Formation reefs on both sides of the Kaijiang-Liangping trough, eastern Sichuan Basin, China 中国四川盆地东部开江-梁平海槽两侧长兴地层礁盘的台缘带结构与沉积特征

IF 2 4区地球科学

Open Geosciences Pub Date : 2024-03-13 DOI: 10.1515/geo-2022-0615

Mingtao Zuo, Jiangong Wang, Xiujian Sun, Zhonggui Hu, Yadong Bai, Wei Yang, Hongzhe Li

{"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}

引用次数: 0

Integrated geophysical approach for detection and size-geometry characterization of a multiscale karst system in carbonate units, semiarid Brazil 采用综合地球物理方法探测巴西半干旱地区碳酸盐岩单元中的多尺度岩溶系统并确定其尺寸-几何特征

IF 2 4区地球科学

Open Geosciences Pub Date : 2024-03-08 DOI: 10.1515/geo-2022-0606

David L. de Castro, Francisco H. R. Bezerra, Josibel G. Oliveira Jr

{"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}

引用次数: 0

Zircon U–Pb ages of the Paleozoic volcaniclastic strata in the Junggar Basin, NW China 中国西北准噶尔盆地古生代火山碎屑岩地层的锆石U-Pb年龄

IF 2 4区地球科学

Open Geosciences Pub Date : 2024-03-05 DOI: 10.1515/geo-2022-0529

Fan Chun

{"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}

引用次数: 0