Pub Date : 2025-03-02DOI: 10.1016/j.sedgeo.2025.106854
Radha Krishna Pillutla , Andrew Tien-Shun Lin , Jen-Chu Yeh , Gueorgui Ratzov , Nathalie Babonneau , Shu-Kun Hsu , Chih-Chieh Su , Serge Lallemand , Ludvig Löwemark
A giant piston core, MD18–3548 (20.07 m) was collected from a perched basin in the Taiwan accretionary wedge, at a water depth of 1752 m. Detailed grain-size analysis, 14C accelerator mass spectrometry (AMS) dating, and computed tomography (X-CT) scans of the core were performed. Four types of lithofacies, namely hemipelagic sediments, silty turbidite-homogenites, turbidites, and thin silty layers, are identified, along with seventeen event beds. A total of fourteen 14C AMS dating were carried out, with the depositional ages of the event beds being calculated based on the sedimentation rate of hemipelagites. The oldest event bed is ∼12 cal kyrs BP, while the youngest event bed is ∼64 cal yrs BP. All seven homogenite units are floored by a thin (usually <10 cm thick), coarsening-upward first and then fining-upward unit, capped by a thick structureless mud totally devoid of bioturbation. The average thickness of homogenite units is ∼150 cm, while the thickest homogenite unit is ∼200 cm. These homogenite units can be compared to similar deposits reported elsewhere and find particularly that these units exhibit a basal layer with gradual coarsening and fining upward trend in grain size. We therefore propose a new depositional model for the silty turbidite-homogenite units in seismically-shaken enclosed basins. This model takes into account the coarsening-then-fining upward deposition of the basal layers, reported for the first time.
{"title":"Origin and deposition of deepwater homogenites from a sedimentological perspective: Examples from offshore SW Taiwan","authors":"Radha Krishna Pillutla , Andrew Tien-Shun Lin , Jen-Chu Yeh , Gueorgui Ratzov , Nathalie Babonneau , Shu-Kun Hsu , Chih-Chieh Su , Serge Lallemand , Ludvig Löwemark","doi":"10.1016/j.sedgeo.2025.106854","DOIUrl":"10.1016/j.sedgeo.2025.106854","url":null,"abstract":"<div><div>A giant piston core, MD18–3548 (20.07 m) was collected from a perched basin in the Taiwan accretionary wedge, at a water depth of 1752 m. Detailed grain-size analysis, <sup>14</sup>C accelerator mass spectrometry (AMS) dating, and computed tomography (X-CT) scans of the core were performed. Four types of lithofacies, namely hemipelagic sediments, silty turbidite-homogenites, turbidites, and thin silty layers, are identified, along with seventeen event beds. A total of fourteen <sup>14</sup>C AMS dating were carried out, with the depositional ages of the event beds being calculated based on the sedimentation rate of hemipelagites. The oldest event bed is ∼12 cal kyrs BP, while the youngest event bed is ∼64 cal yrs BP. All seven homogenite units are floored by a thin (usually <10 cm thick), coarsening-upward first and then fining-upward unit, capped by a thick structureless mud totally devoid of bioturbation. The average thickness of homogenite units is ∼150 cm, while the thickest homogenite unit is ∼200 cm. These homogenite units can be compared to similar deposits reported elsewhere and find particularly that these units exhibit a basal layer with gradual coarsening and fining upward trend in grain size. We therefore propose a new depositional model for the silty turbidite-homogenite units in seismically-shaken enclosed basins. This model takes into account the coarsening-then-fining upward deposition of the basal layers, reported for the first time.</div></div>","PeriodicalId":21575,"journal":{"name":"Sedimentary Geology","volume":"480 ","pages":"Article 106854"},"PeriodicalIF":2.7,"publicationDate":"2025-03-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143551819","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-03-01DOI: 10.1016/j.sedgeo.2025.106853
R. Stalder , D. Jaeger , S. Andò , E. Garzanti , C.M. Chiessi , A.O. Sawakuchi , T. Ludwig , M. Strasser
Quartz grains in sediment carried by the Amazon River and five of its major tributaries were analyzed by FTIR-spectroscopy and secondary ion mass spectrometry to evaluate their potential for provenance analysis. Additionally, heavy mineral analysis was performed in the same samples to support sediment discrimination and provenance interpretation. Average defect water contents in quartz grains carried by branches with headwaters draining the Andes are higher (Solimões River 8.8 wt ppm, Madeira River 7.2 wt ppm) than in branches exclusively draining cratonic areas (Xingu River 6.5 wt ppm, Tapajós River 4.6 wt ppm, Negro River 4.7 wt ppm); values in one Amazon mainstem sample are intermediate with prevalence of the Andean signal (7.7 wt ppm). The average defect water content correlates to the fraction of grains that are defect-water rich (> 10 wt ppm), ranging from 30 to 40 % for the Solimões, Madeira, and Amazon Rivers down to 10–20 % for the Tapajós and Negro Rivers. The average molecular-water signal exhibits a much clearer contrast than the OH-defect signal. Grains from cratonic tributaries (Negro, Tapajós and Xingu rivers) exhibit significantly weaker molecular water signals than grains from Andean tributaries (Solimões and Madeira rivers); slightly weaker than the latter is the signal from grains in the Amazon mainstem, reflecting a mixture of Solimões and Negro rivers quartz in the Amazon mainstem sample.
In contrast, trace-element concentrations widely overlap among samples, preventing any robust discrimination about the sources of quartz grains. Trace metals show a fair correlation between Li and Al in all samples; a weak correlation between Al and Ti (indicative of igneous origin) was observed in Negro, Xingu and Amazon River sands, but not in Solimões, Madeira and Tapajós sands. Boron correlates with Li in Tapajós river and Amazon mainstem samples and with Al in Madeira and Tapajós samples.
Heavy-minerals are mostly amphibole, epidote, augitic clinopyroxene and hypersthene in Solimões River sands largely derived from the Andes, and andalusite, amphibole and epidote in Madeira River sands. Cratonic tributaries contribute durable tourmaline and zircon with andalusite (Negro River) or staurolite and topaz (Tapajós River).
The higher content of OH defects and molecular water in quartz grains derived from the Andes than in those from cratonic areas indicates that this property can provide useful complementary information to discriminate the source of quartz grains, one of the thorniest tasks in provenance analysis.
{"title":"Trace element and OH content of quartz grains in the Amazon river: Potential application in provenance analysis","authors":"R. Stalder , D. Jaeger , S. Andò , E. Garzanti , C.M. Chiessi , A.O. Sawakuchi , T. Ludwig , M. Strasser","doi":"10.1016/j.sedgeo.2025.106853","DOIUrl":"10.1016/j.sedgeo.2025.106853","url":null,"abstract":"<div><div>Quartz grains in sediment carried by the Amazon River and five of its major tributaries were analyzed by FTIR-spectroscopy and secondary ion mass spectrometry to evaluate their potential for provenance analysis. Additionally, heavy mineral analysis was performed in the same samples to support sediment discrimination and provenance interpretation. Average defect water contents in quartz grains carried by branches with headwaters draining the Andes are higher (Solimões River 8.8 wt ppm, Madeira River 7.2 wt ppm) than in branches exclusively draining cratonic areas (Xingu River 6.5 wt ppm, Tapajós River 4.6 wt ppm, Negro River 4.7 wt ppm); values in one Amazon mainstem sample are intermediate with prevalence of the Andean signal (7.7 wt ppm). The average defect water content correlates to the fraction of grains that are defect-water rich (> 10 wt ppm), ranging from 30 to 40 % for the Solimões, Madeira, and Amazon Rivers down to 10–20 % for the Tapajós and Negro Rivers. The average molecular-water signal exhibits a much clearer contrast than the OH-defect signal. Grains from cratonic tributaries (Negro, Tapajós and Xingu rivers) exhibit significantly weaker molecular water signals than grains from Andean tributaries (Solimões and Madeira rivers); slightly weaker than the latter is the signal from grains in the Amazon mainstem, reflecting a mixture of Solimões and Negro rivers quartz in the Amazon mainstem sample.</div><div>In contrast, trace-element concentrations widely overlap among samples, preventing any robust discrimination about the sources of quartz grains. Trace metals show a fair correlation between Li and Al in all samples; a weak correlation between Al and Ti (indicative of igneous origin) was observed in Negro, Xingu and Amazon River sands, but not in Solimões, Madeira and Tapajós sands. Boron correlates with Li in Tapajós river and Amazon mainstem samples and with Al in Madeira and Tapajós samples.</div><div>Heavy-minerals are mostly amphibole, epidote, augitic clinopyroxene and hypersthene in Solimões River sands largely derived from the Andes, and andalusite, amphibole and epidote in Madeira River sands. Cratonic tributaries contribute durable tourmaline and zircon with andalusite (Negro River) or staurolite and topaz (Tapajós River).</div><div>The higher content of OH defects and molecular water in quartz grains derived from the Andes than in those from cratonic areas indicates that this property can provide useful complementary information to discriminate the source of quartz grains, one of the thorniest tasks in provenance analysis.</div></div>","PeriodicalId":21575,"journal":{"name":"Sedimentary Geology","volume":"480 ","pages":"Article 106853"},"PeriodicalIF":2.7,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143551818","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-28DOI: 10.1016/j.sedgeo.2025.106851
Junguang Wang , Zhibao Dong , Zhengcai Zhang , Rongliang Liu , Jiqiao Shi , Ping Lü
Reticulate dunes are the prevalent type of dunes found in deserts worldwide. However, compared to other dune types, systematic research on reticulate dunes remains limited, and aspects such as their formation mechanisms, grain size characteristics, and elemental composition characteristics remain inadequately understood. This study integrated regional wind regime data to analyse the grain size characteristics of reticulate dunes (specifically, the primary and secondary ridges) in the Tengger Desert, Considering both primary and sub-wind seasons. Additionally, we examined the elemental composition characteristics and degree of weathering of these dunes. The results indicate that the primary and secondary ridges of the reticulate dunes in the Tengger Desert are predominantly composed of fine sand and very fine sand with a mean grain size of 2.52Φ. Compared with other deserts in China and abroad, the sediments exhibit relatively finer grain sizes and better sorting. Furthermore, the grain size characteristics of surface sediments in the primary and secondary ridges exhibited two distinct distribution patterns during different wind seasons, indicating differences in the formation mechanisms of the primary and secondary ridges. The major elements in the surface sediments of the reticulate dunes in the Tengger Desert are SiO2 and Al2O3, while the predominant trace elements are primarily Ba, Sr, Zr, and Cr. This indicates that the geochemical composition of the sediments is influenced not only by the intrinsic characteristics of the elements but also by the regional climate and the supply of fresh materials, which are significant factors affecting their chemical behavior and content differences. The chemical weathering indices (CIA, residual coefficient, and ICV), along with the A-CN-K and A-CNK-FM triangular diagrams, suggest that the sedimentary environment of the reticulate dune sediments in the Tengger Desert is characterised by a cold, dry climate with a low degree of weathering. The weathering process occurs during the initial stages of plagioclase chemical weathering. These findings lay the foundation for further research on the formation mechanisms, evolutionary processes, and sedimentary environments of reticulate dunes, contributing to a deeper understanding of these complex geomorphological features.
{"title":"Geochemical composition and grain size of surface sediments from reticulate dunes in the Tengger Desert, China","authors":"Junguang Wang , Zhibao Dong , Zhengcai Zhang , Rongliang Liu , Jiqiao Shi , Ping Lü","doi":"10.1016/j.sedgeo.2025.106851","DOIUrl":"10.1016/j.sedgeo.2025.106851","url":null,"abstract":"<div><div>Reticulate dunes are the prevalent type of dunes found in deserts worldwide. However, compared to other dune types, systematic research on reticulate dunes remains limited, and aspects such as their formation mechanisms, grain size characteristics, and elemental composition characteristics remain inadequately understood. This study integrated regional wind regime data to analyse the grain size characteristics of reticulate dunes (specifically, the primary and secondary ridges) in the Tengger Desert, Considering both primary and sub-wind seasons. Additionally, we examined the elemental composition characteristics and degree of weathering of these dunes. The results indicate that the primary and secondary ridges of the reticulate dunes in the Tengger Desert are predominantly composed of fine sand and very fine sand with a mean grain size of 2.52Φ. Compared with other deserts in China and abroad, the sediments exhibit relatively finer grain sizes and better sorting. Furthermore, the grain size characteristics of surface sediments in the primary and secondary ridges exhibited two distinct distribution patterns during different wind seasons, indicating differences in the formation mechanisms of the primary and secondary ridges. The major elements in the surface sediments of the reticulate dunes in the Tengger Desert are SiO<sub>2</sub> and Al<sub>2</sub>O<sub>3</sub>, while the predominant trace elements are primarily Ba, Sr, Zr, and Cr. This indicates that the geochemical composition of the sediments is influenced not only by the intrinsic characteristics of the elements but also by the regional climate and the supply of fresh materials, which are significant factors affecting their chemical behavior and content differences. The chemical weathering indices (CIA, residual coefficient, and ICV), along with the A-CN-K and A-CNK-FM triangular diagrams, suggest that the sedimentary environment of the reticulate dune sediments in the Tengger Desert is characterised by a cold, dry climate with a low degree of weathering. The weathering process occurs during the initial stages of plagioclase chemical weathering. These findings lay the foundation for further research on the formation mechanisms, evolutionary processes, and sedimentary environments of reticulate dunes, contributing to a deeper understanding of these complex geomorphological features.</div></div>","PeriodicalId":21575,"journal":{"name":"Sedimentary Geology","volume":"480 ","pages":"Article 106851"},"PeriodicalIF":2.7,"publicationDate":"2025-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143551817","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-25DOI: 10.1016/j.sedgeo.2025.106847
Min Ren
Precambrian marine carbonates with distinct sedimentary fabrics and structures provide valuable insights into the chemical and biological conditions of early oceans. To better understand shallow marine environments approaching the terminal Proterozoic, this study examines carbonate deposits from the Ediacaran Doushantuo Formation across the shoal-rimmed Yangtze platform in South China. These mimetically dolomitized rocks comprise facies of micropeloidal leiolite, grainstone-packstone, micropeloidal and microlaminated leiolites, stromatolite, and mudstone, representing a transition from the upper slope and platform margin environments to the back-shoal peritidal system. The grainstone-packstone facies features large intraclasts of incipient aragonite and high-Mg calcite cements, along with radial ooids that are <2 mm in diameter, all exhibiting varying degrees of microbial micritization. The peritidal facies, marked by abundant microbialites, are dominated by micropeloidal-microlaminated leiolites from the intertidal zone and stromatolites and dolomudstones from deeper waters. Abundant fibrous dolomites (fascicular and radial length-slow, up to 5 mm long) fill cavities in the peritidal facies, particularly within microbial mat cracks. Developed on a warm-temperate to tropical shelf, the rapid early lithification of Doushantuo sediments indicates a high degree of seawater supersaturation during the late Neoproterozoic compared to modern conditions. The remarkable diversity in the physical properties of the Doushantuo carbonates reflects an increased compartmentalization of processes governing carbonate formation and dissolution in shallow marine environments. This shift corresponds with the evolving chemical and biological conditions of the Precambrian ocean, which increasingly emphasized microbial roles in dolomite precipitation. By the terminal Proterozoic, platform carbonate formation became more susceptible to local fluctuations affecting saturation states and kinetic conditions, largely influenced by microbial activity.
{"title":"Carbonate sedimentation and early diagenesis of the Doushantuo Formation, South China: A window into the terminal Proterozoic","authors":"Min Ren","doi":"10.1016/j.sedgeo.2025.106847","DOIUrl":"10.1016/j.sedgeo.2025.106847","url":null,"abstract":"<div><div>Precambrian marine carbonates with distinct sedimentary fabrics and structures provide valuable insights into the chemical and biological conditions of early oceans. To better understand shallow marine environments approaching the terminal Proterozoic, this study examines carbonate deposits from the Ediacaran Doushantuo Formation across the shoal-rimmed Yangtze platform in South China. These mimetically dolomitized rocks comprise facies of micropeloidal leiolite, grainstone-packstone, micropeloidal and microlaminated leiolites, stromatolite, and mudstone, representing a transition from the upper slope and platform margin environments to the back-shoal peritidal system. The grainstone-packstone facies features large intraclasts of incipient aragonite and high-Mg calcite cements, along with radial ooids that are <2 mm in diameter, all exhibiting varying degrees of microbial micritization. The peritidal facies, marked by abundant microbialites, are dominated by micropeloidal-microlaminated leiolites from the intertidal zone and stromatolites and dolomudstones from deeper waters. Abundant fibrous dolomites (fascicular and radial length-slow, up to 5 mm long) fill cavities in the peritidal facies, particularly within microbial mat cracks. Developed on a warm-temperate to tropical shelf, the rapid early lithification of Doushantuo sediments indicates a high degree of seawater supersaturation during the late Neoproterozoic compared to modern conditions. The remarkable diversity in the physical properties of the Doushantuo carbonates reflects an increased compartmentalization of processes governing carbonate formation and dissolution in shallow marine environments. This shift corresponds with the evolving chemical and biological conditions of the Precambrian ocean, which increasingly emphasized microbial roles in dolomite precipitation. By the terminal Proterozoic, platform carbonate formation became more susceptible to local fluctuations affecting saturation states and kinetic conditions, largely influenced by microbial activity.</div></div>","PeriodicalId":21575,"journal":{"name":"Sedimentary Geology","volume":"479 ","pages":"Article 106847"},"PeriodicalIF":2.7,"publicationDate":"2025-02-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143527170","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A sedimentological-stratigraphic study of the Mesozoic carbonates exposed in two inactive quarries in southwestern Sicily has provided new insights into the palaeogeographic evolution of the southern sector of the Western Tethys margin during the Jurassic.
The Lower–Upper Jurassic succession consists of shallow-water peritidal carbonates, intersected by neptunian dykes and sills, which transition upwards into condensed pelagic limestone. Microfacies analysis of the shallow-water peritidal carbonates has led to their reassignment to the Hettangian–Pliensbachian (p.p.), previously attributed to the Late Triassic. Furthermore, variations in biodiversity within these stratigraphic horizons reflect the survival and recovery interval following the end-Triassic mass extinction event.
The abrupt transition to condensed pelagic limestone indicates the drowning of the carbonate platform. Lateral facies variations observed within the condensed pelagic limestone suggest different sedimentological processes, influenced by a complex system of structural highs and basins related to the Pangea continental rift. The presence of distinctive micro- and macrofacies, such as micritic oolites and FeMn hardgrounds, indicates a varied palaeotopographic setting for each section, where sedimentation is further controlled by bottom-current activity and low sedimentation rates.
{"title":"Sedimentology of a drowned carbonate platform from the Sciacca area (southwestern Sicily): Insights into the Jurassic palaeogeography of Western Tethys","authors":"Francesca Petrella, Simona Todaro, Carolina D'Arpa, Attilio Sulli","doi":"10.1016/j.sedgeo.2025.106839","DOIUrl":"10.1016/j.sedgeo.2025.106839","url":null,"abstract":"<div><div>A sedimentological-stratigraphic study of the Mesozoic carbonates exposed in two inactive quarries in southwestern Sicily has provided new insights into the palaeogeographic evolution of the southern sector of the Western Tethys margin during the Jurassic.</div><div>The Lower–Upper Jurassic succession consists of shallow-water peritidal carbonates, intersected by neptunian dykes and sills, which transition upwards into condensed pelagic limestone. Microfacies analysis of the shallow-water peritidal carbonates has led to their reassignment to the Hettangian–Pliensbachian (<em>p.p.</em>), previously attributed to the Late Triassic. Furthermore, variations in biodiversity within these stratigraphic horizons reflect the survival and recovery interval following the end-Triassic mass extinction event.</div><div>The abrupt transition to condensed pelagic limestone indicates the drowning of the carbonate platform. Lateral facies variations observed within the condensed pelagic limestone suggest different sedimentological processes, influenced by a complex system of structural highs and basins related to the Pangea continental rift. The presence of distinctive micro- and macrofacies, such as micritic oolites and Fe<img>Mn hardgrounds, indicates a varied palaeotopographic setting for each section, where sedimentation is further controlled by bottom-current activity and low sedimentation rates.</div></div>","PeriodicalId":21575,"journal":{"name":"Sedimentary Geology","volume":"479 ","pages":"Article 106839"},"PeriodicalIF":2.7,"publicationDate":"2025-02-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143519138","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-18DOI: 10.1016/j.sedgeo.2025.106838
Sérgio Francisco Leon Dias , Fernando Farias Vesely , Ronaldo Paulo Kraft , Giovana Rebelo Diório , Guillan Diedrichs Fayad
The Rio Segredo Member of the Taciba Formation (Paraná Basin, Brazil) represents a unique example of a multi-sourced turbidite lobe complex, providing valuable insights into the stratigraphic architecture and depositional processes of delta-fed submarine ramp systems. This study investigates the lobe complex, which extends over 120 km and reaches a thickness of up to 40 m, with a focus on bed type distribution, facies associations, and stratigraphic architecture. Through the analysis of 16 measured sections and detailed facies analysis, 14 distinct bed types were identified, including turbidites (TBDs), hybrid event beds (HEBs), and slump and blocky flow deposits (MTDs). These beds are organized into four sub-environments: lobe axis, lobe off-axis, lobe fringe, and distal lobe fringe, reflecting a compensational stacking pattern with lobe centroids shifting southward by an average of 25 km. Paleocurrent data indicates predominant flow directions to the northwest (320°) and southwest (235°), supporting the interpretation of a multi-sourced system. The lobe complex is interpreted as a delta-fed submarine ramp, with deposition driven by delta-front instabilities and hyperpycnal flows via conduits connected to prograding delta. Hybrid event beds, which are common in the basal sandy portion of the succession, are linked to substrate erosion and interactions with small-scale morphological highs, highlighting the influence of paleophysiography on flow dynamics. This study enhances the understanding of multi-sourced turbidite systems and provides a framework for identifying similar systems in other basins. The findings underscore the importance of autogenic controls, such as lobe avulsion and topographic compensation, in shaping the stratigraphic architecture of delta-fed turbidite systems.
{"title":"Stratigraphic architecture of a multi-sourced, Deepwater lobe complex (early Permian, Paraná basin, Brazil)","authors":"Sérgio Francisco Leon Dias , Fernando Farias Vesely , Ronaldo Paulo Kraft , Giovana Rebelo Diório , Guillan Diedrichs Fayad","doi":"10.1016/j.sedgeo.2025.106838","DOIUrl":"10.1016/j.sedgeo.2025.106838","url":null,"abstract":"<div><div>The Rio Segredo Member of the Taciba Formation (Paraná Basin, Brazil) represents a unique example of a multi-sourced turbidite lobe complex, providing valuable insights into the stratigraphic architecture and depositional processes of delta-fed submarine ramp systems. This study investigates the lobe complex, which extends over 120 km and reaches a thickness of up to 40 m, with a focus on bed type distribution, facies associations, and stratigraphic architecture. Through the analysis of 16 measured sections and detailed facies analysis, 14 distinct bed types were identified, including turbidites (TBDs), hybrid event beds (HEBs), and slump and blocky flow deposits (MTDs). These beds are organized into four sub-environments: lobe axis, lobe off-axis, lobe fringe, and distal lobe fringe, reflecting a compensational stacking pattern with lobe centroids shifting southward by an average of 25 km. Paleocurrent data indicates predominant flow directions to the northwest (320°) and southwest (235°), supporting the interpretation of a multi-sourced system. The lobe complex is interpreted as a delta-fed submarine ramp, with deposition driven by delta-front instabilities and hyperpycnal flows via conduits connected to prograding delta. Hybrid event beds, which are common in the basal sandy portion of the succession, are linked to substrate erosion and interactions with small-scale morphological highs, highlighting the influence of paleophysiography on flow dynamics. This study enhances the understanding of multi-sourced turbidite systems and provides a framework for identifying similar systems in other basins. The findings underscore the importance of autogenic controls, such as lobe avulsion and topographic compensation, in shaping the stratigraphic architecture of delta-fed turbidite systems.</div></div>","PeriodicalId":21575,"journal":{"name":"Sedimentary Geology","volume":"479 ","pages":"Article 106838"},"PeriodicalIF":2.7,"publicationDate":"2025-02-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143474421","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-18DOI: 10.1016/j.sedgeo.2025.106837
Lu Shi , Ziye Lu , Fei Li , Hairuo Qing , Wenzhuo Jiang , Wei Li , Zenghua Li , Ning Ye , Bei Zhu , Qi Tang , Haizhou Qu , Yang Xiao , Shaonan Zhang
Lithological heterogeneity can be an important factor in regulating the spatial distribution of hydrothermal dolostone (HTD) geobodies. Understanding HTD genesis is crucial for improving our ability to predict subsurface HTD occurrence within sedimentary frameworks. This study investigates HTD development within the Permian Guadalupian carbonate successions of the eastern Sichuan Basin, China, providing significant insights into HTD formation processes. Through systematic sedimentological analysis of four outcrop sections (Fangniuba, Shangping, Tuotuoba, and Wuyangba), we identified eight distinct lithofacies and five lithofacies associations (LA1–LA5). Integrating field observations with data from adjacent sites, we performed a comprehensive evaluation of the depositional sequences, sedimentary environments, and petrophysical properties of the Guadalupian carbonate strata. These carbonates display a distinctive shallowing-upward sequence overlain by a deepening-upward succession. Notably, Guadalupian dolostones are consistently hosted within the middle portions of the shallowing-upward sequences across all studied sections. Petrological and mineralogical analyses further reveal preferential dolomitization in thin- to medium-bedded wackestone containing nodular cherts (LA2), which served as lateral conduits for hydrothermal fluid migration. Enhanced fracturing is observed within these lithologies, particularly along bedding planes and around nodular chert margins, reflecting their greater susceptibility to petrophysical modification. This preferential dolomitization reflects the interplay of carbonate texture, rock permeability, and fracture susceptibility, which collectively establish optimal diagenetic conditions for fluid-rock interaction. Our findings demonstrate that depositional lithological heterogeneity constrains HTD distribution through two key pathways: (1) primary lithological controls (including permeability variations and mud content), and (2) mechanically influenced properties (particularly bed thickness and nodular cherts). This heterogeneity, established during initial deposition to shallow-burial phases, fundamentally preconditioned subsequent HTD formation and distribution during later hydrothermal fluid emplacement.
{"title":"Depositional systems constraining the distribution of hydrothermal dolostone geobodies: A case study of Permian Guadalupian dolostone in the eastern Sichuan Basin","authors":"Lu Shi , Ziye Lu , Fei Li , Hairuo Qing , Wenzhuo Jiang , Wei Li , Zenghua Li , Ning Ye , Bei Zhu , Qi Tang , Haizhou Qu , Yang Xiao , Shaonan Zhang","doi":"10.1016/j.sedgeo.2025.106837","DOIUrl":"10.1016/j.sedgeo.2025.106837","url":null,"abstract":"<div><div>Lithological heterogeneity can be an important factor in regulating the spatial distribution of hydrothermal dolostone (HTD) geobodies. Understanding HTD genesis is crucial for improving our ability to predict subsurface HTD occurrence within sedimentary frameworks. This study investigates HTD development within the Permian Guadalupian carbonate successions of the eastern Sichuan Basin, China, providing significant insights into HTD formation processes. Through systematic sedimentological analysis of four outcrop sections (Fangniuba, Shangping, Tuotuoba, and Wuyangba), we identified eight distinct lithofacies and five lithofacies associations (LA1–LA5). Integrating field observations with data from adjacent sites, we performed a comprehensive evaluation of the depositional sequences, sedimentary environments, and petrophysical properties of the Guadalupian carbonate strata. These carbonates display a distinctive shallowing-upward sequence overlain by a deepening-upward succession. Notably, Guadalupian dolostones are consistently hosted within the middle portions of the shallowing-upward sequences across all studied sections. Petrological and mineralogical analyses further reveal preferential dolomitization in thin- to medium-bedded wackestone containing nodular cherts (LA2), which served as lateral conduits for hydrothermal fluid migration. Enhanced fracturing is observed within these lithologies, particularly along bedding planes and around nodular chert margins, reflecting their greater susceptibility to petrophysical modification. This preferential dolomitization reflects the interplay of carbonate texture, rock permeability, and fracture susceptibility, which collectively establish optimal diagenetic conditions for fluid-rock interaction. Our findings demonstrate that depositional lithological heterogeneity constrains HTD distribution through two key pathways: (1) primary lithological controls (including permeability variations and mud content), and (2) mechanically influenced properties (particularly bed thickness and nodular cherts). This heterogeneity, established during initial deposition to shallow-burial phases, fundamentally preconditioned subsequent HTD formation and distribution during later hydrothermal fluid emplacement.</div></div>","PeriodicalId":21575,"journal":{"name":"Sedimentary Geology","volume":"479 ","pages":"Article 106837"},"PeriodicalIF":2.7,"publicationDate":"2025-02-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143519137","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-17DOI: 10.1016/j.sedgeo.2025.106836
Sabrina Lizzoli , M. Sol Raigemborn , Augusto N. Varela , José M. Paredes
The paleosols preserved in the Bajo Barreal Formation in central Patagonia (Argentina) provide valuable insights into mid-Cretaceous paleoclimatic conditions at mid-paleolatitudes in the Southern Hemisphere. This study integrates macro-, micro-, and nanomorphological analyses, clay mineralogy, and geochemical data to characterize and classify the Bajo Barreal's paleosols and reconstruct their paleoclimate conditions. The Cerro Ballena anticline's exposure begins with isolated, small-scale channel belts of low connectivity within siliciclastic mudstones (Section A). Upwards, it transitions into sheet-like, interconnected channel-belt complexes interbedded with thinner volcaniclastic floodplain deposits (Section B). We identified four pedotypes in stratigraphic order of appearance: Cerro Guacho (vertic Alfisols-like paleosols), Cañadón Vasco (Vertisols-like paleosols), San Bernardo (Ultisols-like paleosols), and Río Deseado (hydromorphic Inceptisols-like paleosols). Section A contains smectite-rich vertic Alfisols-like paleosols and Vertisols-like paleosols formed under moderate weathering, dominated by argilluviation, vertization, hydromorphism, and calcification. Section B, in contrast, contains kaolinite-rich Ultisols-like paleosols and hydromorphic Inceptisols-like paleosols formed under intense weathering conditions, dominated by lixiviation (ferruginization) accompanied by argilluviation and hydromorphism. This progression reflects a transition from temperate and subhumid conditions with seasonal rainfall (Section A) to warmer (temperate) and humid conditions with perennial rainfall (Section B). This vertical progression parallels mid-Cretaceous global climate dynamics and potentially reflects changes near the Cenomanian–Turonian boundary and OAE 2, offering valuable contributions to refine Southern Hemisphere paleoclimate reconstructions.
{"title":"Paleosols as paleoclimate proxies to reconstruct mid-Cretaceous paleoclimate conditions in Central Patagonia, Argentina","authors":"Sabrina Lizzoli , M. Sol Raigemborn , Augusto N. Varela , José M. Paredes","doi":"10.1016/j.sedgeo.2025.106836","DOIUrl":"10.1016/j.sedgeo.2025.106836","url":null,"abstract":"<div><div>The paleosols preserved in the Bajo Barreal Formation in central Patagonia (Argentina) provide valuable insights into mid-Cretaceous paleoclimatic conditions at mid-paleolatitudes in the Southern Hemisphere. This study integrates macro-, micro-, and nanomorphological analyses, clay mineralogy, and geochemical data to characterize and classify the Bajo Barreal's paleosols and reconstruct their paleoclimate conditions. The Cerro Ballena anticline's exposure begins with isolated, small-scale channel belts of low connectivity within siliciclastic mudstones (Section A). Upwards, it transitions into sheet-like, interconnected channel-belt complexes interbedded with thinner volcaniclastic floodplain deposits (Section B). We identified four pedotypes in stratigraphic order of appearance: Cerro Guacho (vertic Alfisols-like paleosols), Cañadón Vasco (Vertisols-like paleosols), San Bernardo (Ultisols-like paleosols), and Río Deseado (hydromorphic Inceptisols-like paleosols). Section A contains smectite-rich vertic Alfisols-like paleosols and Vertisols-like paleosols formed under moderate weathering, dominated by argilluviation, vertization, hydromorphism, and calcification. Section B, in contrast, contains kaolinite-rich Ultisols-like paleosols and hydromorphic Inceptisols-like paleosols formed under intense weathering conditions, dominated by lixiviation (ferruginization) accompanied by argilluviation and hydromorphism. This progression reflects a transition from temperate and subhumid conditions with seasonal rainfall (Section A) to warmer (temperate) and humid conditions with perennial rainfall (Section B). This vertical progression parallels mid-Cretaceous global climate dynamics and potentially reflects changes near the Cenomanian–Turonian boundary and OAE 2, offering valuable contributions to refine Southern Hemisphere paleoclimate reconstructions.</div></div>","PeriodicalId":21575,"journal":{"name":"Sedimentary Geology","volume":"478 ","pages":"Article 106836"},"PeriodicalIF":2.7,"publicationDate":"2025-02-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143453610","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-10DOI: 10.1016/j.sedgeo.2025.106833
Szymon Świątek, Małgorzata Pisarska-Jamroży
Seismically liquefaction-induced soft-sediment deformation structures are key to understanding the geological history of earthquakes and sedimentary environments. These evidences usually have been associated with high-magnitude seismic events, above 5. However, the precise thresholds and mechanisms, especially for lower-magnitude earthquakes, remained unclear. This study aims to address this gap by experimentally investigating the development of deformation structures under controlled laboratory conditions. Using three sediment types arranged in five sequences, the sediments were subjected to low-magnitude seismic vibrations. Developed liquefaction features such as clastic volcanoes, pseudonodules, flame structures, and load casts were measured by a novel morphometric analysis to quantify their size and shape. The findings revealed that even at a magnitude of ∼3.5, liquefaction and deformation structures can occur, especially in high water-saturated fine-grained sediments. These results provide new insights into the thresholds of seismically-induced liquefaction and highlight the importance of considering lower-magnitude events in seismic risk assessments, offering significant implications for the study of sedimentary processes and earthquake-related deformation.
{"title":"Seismogenic liquefaction with M ∼ 3.5 in fine-grained sediments: An experimental approach","authors":"Szymon Świątek, Małgorzata Pisarska-Jamroży","doi":"10.1016/j.sedgeo.2025.106833","DOIUrl":"10.1016/j.sedgeo.2025.106833","url":null,"abstract":"<div><div>Seismically liquefaction-induced soft-sediment deformation structures are key to understanding the geological history of earthquakes and sedimentary environments. These evidences usually have been associated with high-magnitude seismic events, above 5. However, the precise thresholds and mechanisms, especially for lower-magnitude earthquakes, remained unclear. This study aims to address this gap by experimentally investigating the development of deformation structures under controlled laboratory conditions. Using three sediment types arranged in five sequences, the sediments were subjected to low-magnitude seismic vibrations. Developed liquefaction features such as clastic volcanoes, pseudonodules, flame structures, and load casts were measured by a novel morphometric analysis to quantify their size and shape. The findings revealed that even at a magnitude of ∼3.5, liquefaction and deformation structures can occur, especially in high water-saturated fine-grained sediments. These results provide new insights into the thresholds of seismically-induced liquefaction and highlight the importance of considering lower-magnitude events in seismic risk assessments, offering significant implications for the study of sedimentary processes and earthquake-related deformation.</div></div>","PeriodicalId":21575,"journal":{"name":"Sedimentary Geology","volume":"478 ","pages":"Article 106833"},"PeriodicalIF":2.7,"publicationDate":"2025-02-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143419730","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-03DOI: 10.1016/j.sedgeo.2025.106825
Ming-wei Ma , Jia-wen Zhou , Xing-guo Yang , Yi-hui Liang , Tao Yang , Hai-mei Liao
This study explores the impact of granular materials with varying moisture contents and particle sizes, as well as block materials with different volumes and layer strengths, on landslide fragmentation, motion, and deposit. The experimental results show that as particle size increases, the maximum dam height (Hmax) and width (Wmax) increase, while the minimum dam height (Hmin) decreases, indicating an improvement in the stability of landslide dams. Larger particle sizes are less sensitive to changes in moisture content. Additionally, moisture content inhibits Wmax, with mixed particle-size materials showing a greater reduction compared to single particle-size materials. As Wmax increases, the maximum dam length (Lmax) decreases exponentially. Sliding time (Ts), deposition time (Td), and total time (T) decrease as particle size increases. For mixed particle-size materials, a more continuous particle size distribution further reduces Ts, Td, and T. Block material experiments show that with increasing block volume, Wmax, Lmax, and Hmax increase significantly, with corresponding increases in Ts, Td, and T. When the strength of the lower layer material decreases, Wmax and Hmax decrease, while Ts, Td, and T increase. Conversely, when the lower layer material strength increases, the opposite effect is observed. Frictional energy loss (Ef) is the primary energy loss pathway, with both total energy loss and Ef decreasing with increasing particle size. Localized energy losses are mainly due to terrain collisions, independent of moisture content.
{"title":"Experiments study on landslide motion and damming deposit for particle and block materials with different mechanical properties","authors":"Ming-wei Ma , Jia-wen Zhou , Xing-guo Yang , Yi-hui Liang , Tao Yang , Hai-mei Liao","doi":"10.1016/j.sedgeo.2025.106825","DOIUrl":"10.1016/j.sedgeo.2025.106825","url":null,"abstract":"<div><div>This study explores the impact of granular materials with varying moisture contents and particle sizes, as well as block materials with different volumes and layer strengths, on landslide fragmentation, motion, and deposit. The experimental results show that as particle size increases, the maximum dam height (<em>H</em><sub><em>max</em></sub>) and width (<em>W</em><sub><em>max</em></sub>) increase, while the minimum dam height (<em>H</em><sub><em>min</em></sub>) decreases, indicating an improvement in the stability of landslide dams. Larger particle sizes are less sensitive to changes in moisture content. Additionally, moisture content inhibits <em>W</em><sub><em>max</em></sub>, with mixed particle-size materials showing a greater reduction compared to single particle-size materials. As <em>W</em><sub><em>max</em></sub> increases, the maximum dam length (<em>L</em><sub><em>max</em></sub>) decreases exponentially. Sliding time (<em>T</em><sub><em>s</em></sub>), deposition time (<em>T</em><sub><em>d</em></sub>), and total time (<em>T</em>) decrease as particle size increases. For mixed particle-size materials, a more continuous particle size distribution further reduces <em>T</em><sub><em>s</em></sub>, <em>T</em><sub><em>d</em></sub>, and <em>T</em>. Block material experiments show that with increasing block volume, <em>W</em><sub><em>max</em></sub>, <em>L</em><sub><em>max</em></sub>, and <em>H</em><sub><em>max</em></sub> increase significantly, with corresponding increases in <em>T</em><sub><em>s</em></sub><em>, T</em><sub><em>d</em></sub>, and <em>T</em>. When the strength of the lower layer material decreases, <em>W</em><sub><em>max</em></sub> and <em>H</em><sub><em>max</em></sub> decrease, while <em>T</em><sub><em>s</em></sub><em>, T</em><sub><em>d</em></sub>, and <em>T</em> increase. Conversely, when the lower layer material strength increases, the opposite effect is observed. Frictional energy loss (<em>E</em><sub><em>f</em></sub>) is the primary energy loss pathway, with both total energy loss and <em>E</em><sub><em>f</em></sub> decreasing with increasing particle size. Localized energy losses are mainly due to terrain collisions, independent of moisture content.</div></div>","PeriodicalId":21575,"journal":{"name":"Sedimentary Geology","volume":"478 ","pages":"Article 106825"},"PeriodicalIF":2.7,"publicationDate":"2025-02-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143336963","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
扫码关注我们
求助内容：
应助结果提醒方式：
京公网安备 11010802042870号