Frontiers in Earth Science最新文献

{"title":"Analysis on the dynamics of flexible drillstring under different drilling parameters","authors":"Jifei Cao, Deyong Zou, Qilong Xue, Jin Wang, Leilei Huang, Feng Guo, Chong Wang, Jun Qu","doi":"10.3389/feart.2024.1396784","DOIUrl":"https://doi.org/10.3389/feart.2024.1396784","url":null,"abstract":"During the operation of the drill string, it displays a degree of flexibility. Simultaneously, its dynamic properties, influenced by complex stress conditions, manifest nonlinearity and uncertainty. A comprehensive investigation into the dynamics of flexible drill strings is imperative for deep well drilling. This paper presents a model that simulates random interactions between a flexible drill string and the borehole wall, simplifying the actual drill string model using analogous principles. Dynamic simulation software is utilized for analysis, and an indoor experimental setup has been established. The results reveal that with a constant weight on bit (WOB), higher drill string rotational speeds correlate with increased susceptibility to buckling deformation. Additionally, the critical time for deformation onset exhibits a nearly linear relationship with rotational speed. Maintaining a constant rotational speed, an increase in WOB enhances the likelihood of buckling deformation. The experimental findings suggest a correlation between the drill string’s rotation frequency and the WOB.","PeriodicalId":12359,"journal":{"name":"Frontiers in Earth Science","volume":"9 1","pages":""},"PeriodicalIF":2.9,"publicationDate":"2024-08-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142179668","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Frontiers | Integrated surface-subsurface reservoir zonation of the Early Bartonian nummulitic limestone in central Tunisia and eastern Tunisian offshore","authors":"Jihede Haj Messaoud, Nicolas Thibault, Brahimsamba Bomou, Thierry Adatte, Mohammed H. Aljahdali, Chokri Yaich","doi":"10.3389/feart.2024.1452977","DOIUrl":"https://doi.org/10.3389/feart.2024.1452977","url":null,"abstract":"The Early Bartonian Reneiche/Siouf member is one of the primary conventional carbonate oil/gas reservoirs to be assessed in Tunisia that demands detailed evaluation. Accurate zonation and modeling of this reservoir require an integrated approach combining surface and subsurface studies. This research focuses on the depositional, diagenetic, and stratigraphic factors affecting reservoir quality and porosity within the Reneiche/Siouf member, utilizing an integrated surface-subsurface analysis. The primary aim is to understand the reservoir zonation of the Reineche Member near Kerkennah archipelago (eastern Tunisian offshore) and its lateral equivalents in central Tunisia the Siouf Member (outcrop analogue). Gamma-ray and sonic logs from the Reineche Member in the southern and southeastern Pelagian Platform (Tunisian offshore) identify three distinct limestone units (A, C, and E). These units transition into a single mud-dominated limestone unit (C) to the east and northeast of the Kerkennah archipelago. In contrast, the western Pelagian Platform (onshore) and Central Tunisia present a different stratigraphy for the Reineche/Siouf Member, comprising two limestone units: the Lower Reneiche Limestone (LRL) and the Upper Reneiche Limestone (URL), corresponding to Units C and E, respectively, separated by the Upper Reneiche Shale (URS) unit. Reservoir porosity and permeability analyses of the outcrop analogs reveal hybrid pore types (depositional and diagenetic), including intragranular, biomouldic, and vuggy pores, resulting from significant dissolution of large bioclasts. In the northern Gulf of Gabes, the Nummulite barrier of the Reineche Member (SW of the Kerkennah archipelago) demonstrates substantial reservoir quality improvement, with porosity reaching up to 30% in Unit C, attributed to intense dissolution, dolomitization (intercrystalline porosity), and fracturing. Diagenetic processes observed in the Siouf Member (Central Tunisia) differ from those in the Reineche Limestone Member (Pelagian Platform). In the Reineche Member, CO2-rich fluids entering through faults and fissures during deep burial diagenesis drive dissolution and dolomitization. Conversely, in the Siouf Member, these processes occur due to short subaerial exposures during meteoric to shallow-burial diagenesis. A key outcome of our study is the comparison between Central Tunisia and the eastern Tunisian offshore, highlighting local tectonic control on reservoir thickness and identifying three upward-thickening sequences in the Siouf Member outcrop. This research is crucial for understanding the Gulf of Gabes and Libyan offshore nummulitic Eocene reservoirs, emphasizing the role of tectonics and sea level changes in shaping reservoir characteristics.","PeriodicalId":12359,"journal":{"name":"Frontiers in Earth Science","volume":"95 1","pages":""},"PeriodicalIF":2.9,"publicationDate":"2024-08-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142227599","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Post-stack multi-scale fracture prediction and characterization methods for granite buried hill reservoirs: a case study in the Pearl River Mouth Basin, South China Sea","authors":"Junping Liu, Huailai Zhou, Luyao Liao, Cong Niu, Qiuyu Li","doi":"10.3389/feart.2024.1456122","DOIUrl":"https://doi.org/10.3389/feart.2024.1456122","url":null,"abstract":"Granite buried hill oil and gas reservoirs are relatively scarce worldwide, and the fine prediction and characterization of their fractures have always been a significant industry challenge. Particularly in the South China Sea region, large and thick granite buried-hill reservoirs are influenced by various geological processes such as weathering and tectonics, resulting in a complex internal fracture system. The seismic reflection characteristics exhibit high steepness, discontinuity, and significant amplitude differences, posing significant difficulties for the fine characterization of fractures. A systematic and comprehensive research approach has not yet been established. Therefore, this study considers the large granite-buried hill A reservoir in the South China Sea as a typical case study and proposes a multi-scale fracture fine prediction and characterization methodology system. The method starts with analyzing the fracture scale and genesis to refine the fracture scales identifiable by conventional seismic data. Based on this, the U-SegNet model and transfer learning are utilized to achieve fine detection of large-scale fractures. Meanwhile, using high-resolution ant tracking technology based on MVMD frequency division and sensitive attribute preferences realizes a fine prediction of medium-to-small-scale fractures. Furthermore, the discrete fracture network is used for fracture deterministic modeling, ranging from geometric morphology to percolation behavior. Ultimately, a post-stack seismic multi-scale fracture prediction and characterization workflow is established. The results indicate that the buried hill in the study area exhibits a high degree of fracture development with evident multi-scale characteristics. Among them, large-scale fractures have a relatively low development density, primarily oriented in the NW and NE directions; medium-to-small-scale fractures exhibit high-density and omnidirectional development. The development of fractures significantly improves the storage space and fluid flow capacity of the buried hill. Compared with traditional methods, the proposed method notably enhances the accuracy of characterizing the degree of fracture development, spatial morphology, and percolation behavior in the buried hill reservoir, providing a scientific basis for oil and gas exploration and development.","PeriodicalId":12359,"journal":{"name":"Frontiers in Earth Science","volume":"20 1","pages":""},"PeriodicalIF":2.9,"publicationDate":"2024-08-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142179563","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Frontiers | Shale reservoir characterization and implications for the exploration and development of the upper Permian Wujiaping Formation, Longmen-Wushankan area, eastern Sichuan Basin","authors":"Wen Tang, Cong Tuo, Shaoguang Ma, Yongjun Yao, Dongxi Liu, Xinrui Yang, Licheng Yang, Hu Li","doi":"10.3389/feart.2024.1453098","DOIUrl":"https://doi.org/10.3389/feart.2024.1453098","url":null,"abstract":"Recent exploration efforts have revealed significant industrial gas flow from the Wujiaping Formation marine shale in the Longmen–Wushankan area of the eastern Sichuan Basin, underscoring its considerable exploration potential. In this study, the reservoir characteristics and exploration potential of the Wujiaping Formation shale gas in this area are further evaluated. On the basis of well rock electrical properties, experimental analyses, and depositional and structural patterns in the eastern region, we characterize the reservoir properties and identify the primary factors controlling shale gas accumulation. The results indicate that the Wujiaping shale is characterized by a high organic matter content, favorable pore types, high porosity, and a high content of brittle minerals, which are conducive to subsequent development and fracturing. A positive correlation is observed between the total organic carbon (TOC) content, porosity, brittle mineral content, and shale gas content. The TOC content is strongly correlated with the gas content (the correlation coefficient is 0.75). The high shale gas yield of the Wujiaping Formation is attributed to a combination of favorable sedimentary environments, pore conditions, roof and floor conditions, and fracturing capabilities. However, compared with the Longmaxi Formation in the Sichuan Basin, the Wujiaping Formation shale is characterized by a lower porosity, thinner shale, and deeper burial, posing challenges for exploration and development. In this study, criteria for evaluating Wujiaping Formation shale gas are established, and four favorable exploration areas are identified. Overall, the Permian Wujiaping Formation marine shale in the Longmen–Wushankan area holds promising exploration and development potential. Further exploration and an enhanced understanding of this formation will provide valuable guidance for future marine shale gas exploration and development in this area.","PeriodicalId":12359,"journal":{"name":"Frontiers in Earth Science","volume":"56 1","pages":""},"PeriodicalIF":2.9,"publicationDate":"2024-08-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142179583","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Late Quaternary activity of Wulashan Northern fault, North China","authors":"Leihua Wei, Weimin He, Yueren Xu, Yanlin Du, Aopeng Dai, Xiaopeng Song, Shuya Xu, Jingjing Qin","doi":"10.3389/feart.2024.1437012","DOIUrl":"https://doi.org/10.3389/feart.2024.1437012","url":null,"abstract":"The Late Quaternary activity characteristics of secondary faults located between the main active faults at the boundaries of large basins are of great significance to the overall understanding of regional seismic hazards. The Wulashan Northern Fault (WNF) is located on the northern side of the Ordos Block, within the Northern Margin Fault Basin in North China, between the Sertengshan Piedmont Fault and Daqingshan Piedmont Fault. Current research on the geometry and kinematics of the WNF needs to be improved. In this study, we aimed to determine the shallow structural characteristics and Late Quaternary activity of the WNF using shallow seismic exploration and composite drilling geological cross-sectional analysis. The results indicate that the WNF is not a single surface fault but multiple branches with a northward-dipping stepped surface distribution. The latest activity of the F1 branch with a maximum coseismic vertical dislocation of 0.9 m occurred before 47.08 ± 3.7 ka B.P. The latest and older activities of the branch of F2 with a maximum coseismic vertical dislocation of 0.96 m and 1.15 m occurred before 73.8 ± 2.8 ka B.P. and 91.2 ± 4.4 ka B.P., respectively. According to a series of empirical relationships between length of surface rupture and magnitude, the maximum potential magnitude of the earthquake was determined to be <jats:italic>M</jats:italic> = 6.5–7.0. We argue that even though the Late Quaternary activity of the WNF was weaker than that of the other boundary faults of the Hetao Basin, the local urban and rural planning and land and resources construction in the Hetao Basin region should pay attention to the seismic risk of the WNF as an independent section in the future for the effect of secular tectonic loading.","PeriodicalId":12359,"journal":{"name":"Frontiers in Earth Science","volume":"170 1","pages":""},"PeriodicalIF":2.9,"publicationDate":"2024-08-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142179585","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Multi-scale fracture patterns and their effects on gas enrichment in tight sandstones: a case study of the Upper Paleozoic in the Qingshimao gas field, Ordos Basin, China","authors":"Jie Wang, Jiping Wang, Yuanyuan Zhang, Daofeng Zhang, Lei Sun, Jianning Luo, Wei Wang, Lei Gong, Zongbao Liu, Shuai Gao","doi":"10.3389/feart.2024.1448238","DOIUrl":"https://doi.org/10.3389/feart.2024.1448238","url":null,"abstract":"A well-connected network formed by multi-scale fractures is a key factor in the formation of high-quality reservoirs and the achievement of high and stable oil and gas production in tight sandstones. Taking the Upper Paleozoic of the Qingshimao gas field in the Ordos Basin, China, as an example, based on data from image logs, cores, and thin sections, fine quantitative characterization of multi-scale natural fractures in tight sandstone reservoirs was carried out. We also established a method for dividing network patterns of multi-scale fractures and discussed the effect of each fracture network pattern on the gas enrichment and production capacity. Results indicate regular changes in the length, density, aperture, porosity, permeability, and connectivity of natural fractures at different scales. Based on the spatial combination patterns and connectivity of fractures of different scales, four types of fracture network patterns were established: multi-scale fracture network with high density and multi-orientations, multi-scale fracture network with moderate-high density and dual orientations, small-scale fracture network with moderate density and dual orientations, small-scale fracture network with low density and single orientation. The first fracture network pattern can destroy the integrity of the cap layer, causing natural gas leakage. The second fracture network pattern is a favorable area for natural gas enrichment. The third fracture network pattern requires the use of hydraulic fracturing to obtain commercial airflow. The fourth fracture network pattern has little effect on reservoir control and storage. The study of natural fractures in tight sandstone reservoirs is usually based on a single-scale perspective. Understanding the development characteristics of multi-scale fractures and their controlling effects on the reservoir helps to comprehensively understand the spatial configuration relationship of multi-scale fracture network structure patterns and promotes the development of multi-scale fractures in tight reservoir research.","PeriodicalId":12359,"journal":{"name":"Frontiers in Earth Science","volume":"11 1","pages":""},"PeriodicalIF":2.9,"publicationDate":"2024-08-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142223643","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Impact of regional economic development on the spatiotemporal changes of coastlines: a case study of Ningbo-Taizhou-Wenzhou region","authors":"Qiyu Huang, Yifan Li, Shunyi Ai, Yuxin Chen, Yongchao Liu","doi":"10.3389/feart.2024.1428097","DOIUrl":"https://doi.org/10.3389/feart.2024.1428097","url":null,"abstract":"Introduction: Coastal areas are densely populated, economically developed, and form complex social-ecological systems. Any regional changes within these areas have profound consequences for their socio-economic development and ecological environments.Methods: Based on multi-source remote sensing image data, a detailed analysis of the coastline of the Ningbo-Taizhou-Wenzhou region (Yong-Tai-Wen region) from 1980 to 2020 was conducted, and the spatiotemporal changes of the coastline were analyzed. Regression analysis was employed to investigate the correlation between the coastline length and various factors, including the degree of industrialization, GDP, urban land, and arable land.Results and Discussion: The results show that: 1) From 1980 to 2020, the overall length of the coastline in the Yong-Tai-Wen region exhibited a decreasing trend, accompanied by a continual increase in the degree of artificial coastline. Consequently, the coastline became increasingly fragmented and tortuous. Notably, the intensity of coastline change fluctuated significantly, peaking in 2010. 2) At the regional scale, there is a strong negative correlation between the length of the coastline in the Yong-Tai-Wen region and GDP and land use, whereas the correlation with cultivated land area remains relatively low. Conversely, the proportion of human-made coastlines demonstrates a strong positive correlation with GDP and urban land use but a significant negative correlation with cultivated land area. 3) At the city scale, the length of the coastline in Ningbo shows a significant negative correlation with GDP while exhibiting a certain correlation with urban land use. Similarly, the coastline length in Taizhou also displays a strong negative association with both GDP and urban land use. In contrast, the correlation patterns observed in Wenzhou are opposite to those in Taizhou. Notably, the correlation between the length of the coastline and cultivated land area remains relatively weak across all three cities. Additionally, the proportion of artificial coastlines in Ningbo and Taizhou aligns with the overall trend in the Yong-Tai-Wen region. Specifically, the proportion of artificial coastlines in Wenzhou exhibits a positive correlation with GDP and urban land use and a negative correlation with cultivated land area.","PeriodicalId":12359,"journal":{"name":"Frontiers in Earth Science","volume":"28 1","pages":""},"PeriodicalIF":2.9,"publicationDate":"2024-08-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142179584","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Internal erosion process and its influence factors in widely graded loose soils due to rainfall infiltration","authors":"Li Liang, Da-Lang Tian, Zheng-Chuan Li","doi":"10.3389/feart.2024.1418293","DOIUrl":"https://doi.org/10.3389/feart.2024.1418293","url":null,"abstract":"Compared with engineering materials for earth structures subjected to prolonged, sustained hydraulic loading, the internal erosion process of widely graded loose soils (WGLS) under short-term, fluctuating hydraulic loading conditions remains insufficiently elucidated. Therefore, a novel fixed-wall permeameter is developed, capable of applying hydraulic loading at a constant flow rate and collecting effluent flowing out of specimens. A testing protocol is proposed to separate eroded silty clay particles, sandy gravel particles, and seepage water from the collected effluent. Several seepage tests are conducted on remolded specimens with various initial porosity at different inflow rates. The test results show that under a constant inflow rate, the WGLS specimens may undergo suffusion, suffosion, and stabilization stages while seeking the ultimate equilibrium state. The proposed particle migration pattern adeptly reveals the microscale mechanisms of the internal erosion phenomena observed at different stages. The inflow rate is independent of the suffusion critical hydraulic gradient but impacts the suffosion critical hydraulic gradient and internal erosion behavior following suffusion. Because hydraulic shear stress is a comprehensive indicator that considers both hydraulic gradient and initial porosity, it is more appropriate to use it to evaluate the internal stability potential of WGLS.","PeriodicalId":12359,"journal":{"name":"Frontiers in Earth Science","volume":"25 1","pages":""},"PeriodicalIF":2.9,"publicationDate":"2024-08-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142223624","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Investigation of methane gas bubble dynamics and hydrate film growth during hydrate formation using 4-D time-lapse synchrotron X-ray computed tomography","authors":"Shadman H. Khan, Sourav Kumar Sahoo, Ismael Himar Falcon-Suarez, Hector Marin-Moreno, Hanif Sutiyoso, B. N. Madhusudhan, C. B. Majumder, Amit Arora, Angus I. Best","doi":"10.3389/feart.2024.1438185","DOIUrl":"https://doi.org/10.3389/feart.2024.1438185","url":null,"abstract":"We present a time-lapse 4-D high-resolution synchrotron imaging study of the morphological evolution of methane gas bubbles and hydrate film growth on these bubbles. Methane gas and partially water-saturated sand were used to form hydrate with a maximum hydrate saturation of 60%. We investigated the transient evolution of gas bubble size distribution during hydrate formation and observed three distinct stages: a) nucleation and hydrate film formation, b) rapid bubble break-up, c) gas bubble coalescence and hydrate framework formation. Our results show that the average gas bubble size distribution decreases from 34.17 µm (during hydrate nucleation) to 8.87 µm (during secondary bubble formation). The small-size methane bubble population (mean diameter below 10 µm) initially increases at the expense of the larger methane bubble population (mean diameter above 50 µm) due to breakage of the larger bubbles and coalescence of the smaller bubbles. We quantified that the average hydrate film thickness increases from 3.51 to 14.7 µm by tracking the evolution of a particular gas bubble. This thickness increase agrees with an analytical model with an average deviation error of 3.3%. This study provides insights into gas bubble distribution and hydrate film growth during hydrate formation, both of which impact the geophysical and mechanical properties of hydrate-bearing sediments.","PeriodicalId":12359,"journal":{"name":"Frontiers in Earth Science","volume":"6 1","pages":""},"PeriodicalIF":2.9,"publicationDate":"2024-08-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142179586","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Tectonic evolution of the Northeastern Paleo-Tethys Ocean during the late Triassic: insights from depositional environment and provenance of the Xujiahe formation","authors":"Fenquan Xie, Wenzhou Xiao, Mabrouk Sami, Ioan V. Sanislav, Mohamed S. Ahmed, Chenguang Zhang, Yongkui Wang, Bingpeng Yan, Bing Hu, Ning Li, Douaa Fathy","doi":"10.3389/feart.2024.1444679","DOIUrl":"https://doi.org/10.3389/feart.2024.1444679","url":null,"abstract":"The Triassic tectonic evolution and affinity among the Yangtze Block, Qinling Orogenic Belt and Songpan-Ganzi Terrane remain subjects of ongoing scientific debate. In this context, the sedimentary rocks of Xujiahe Formation (second segment) (T<jats:sub>3</jats:sub>x<jats:sub>2</jats:sub>) represent an ideal case for addressing this issue. In this study, new stratigraphic, geochemical and detrital zircon analyses have been conducted on two sections of the T<jats:sub>3</jats:sub>x<jats:sub>2</jats:sub>. The stratigraphic assemblage and features suggests a braided delta as the depositional setting. Whole-rock geochemical results indicate that the sandstones from the T<jats:sub>3</jats:sub>x<jats:sub>2</jats:sub> exhibit moderate palaeo-weathering and primarily originate from upper crustal felsic rocks, mostly S-type granites. The detrital zircons within these sandstones display distinctive age peaks at intervals of 200–300 Ma, 700–900 Ma, and 1800–2000 Ma, similar to those from the Qinling Orogenic Belt. Both the clastic particle composition and whole-rock geochemistry indicates that the T<jats:sub>3</jats:sub>x<jats:sub>2</jats:sub> sections were deposited in a tectonic environment transitioning from a passive to an active continental margin, highlighted by a braided delta influenced by rivers flowing from the northeast to the southwest.","PeriodicalId":12359,"journal":{"name":"Frontiers in Earth Science","volume":"30 1","pages":""},"PeriodicalIF":2.9,"publicationDate":"2024-08-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142223642","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}