Pub Date : 2025-07-05DOI: 10.1016/j.sedgeo.2025.106930
Maqsood Ur Rahman , Tao Jiang , Muhammad Sarim , Qianru Wang , Cong Cheng
The Late Quaternary is a crucial period marked by glacial-interglacial cycles that significantly impacted global paleoceanography and paleoclimate, making the reconstruction of terrigenous input in the southeastern Indian Ocean vital for understanding these shifts. We present a terrigenous sediment record from International Ocean Discovery Program Site U1516 in the offshore Mentelle Basin, reconstructing sediment provenance, transport mechanisms, and paleoclimate variability over the last 766 ky (MIS18-1). Grain-size analysis reveals a silt-dominated assemblage, with median grain size coarsening during glacial periods, reflecting enhanced winnowing of fine particles, while elevated clay concentrations suggest greater resistance to winnowing and increased supply from shallow shelves due to sea-level decline. Clay mineral assemblages show dominance of kaolinite and illite during interglacials, contrasting with peaks in smectite and chlorite during glacials. These patterns are attributed to sources in southwestern Australia transported by the Leeuwin Current, which delivered more kaolinite and illite during intensified interglacials and shifted to finer-grained smectite during weakened glacials. Elevated chlorite during glacials likely derives from deep marine settings south of Australia or Antarctica, transported via Antarctic Intermediate Water and Leeuwin Undercurrent. This variability highlights glacial-interglacial shifts in sediment routing tied to ocean circulation changes. Contrary to earlier observations of ‘dry glacials’ in southern Australia, data from Hole U1516B (illite crystallinity, chemical indices) reveal the presence of both wet and dry periods during glacials that were previously assumed to be solely dry, aligning with speleothem records but conflicting with bulk geochemical interpretations. This highlights the need for proxy-specific calibration. Interglacial periods also show intensified wetter intervals similar to those during glacials. These glacial-interglacial wetter intervals are likely driven by latitudinal shifts in the Southern Hemisphere westerly winds. This study provides new insights into glacial-interglacial transitions, linking oceanic circulation shifts, sediment transport dynamics, and hydroclimate variability in southwest Western Australia.
{"title":"Late Quaternary oceanographic controls on sediment distribution and transportation in the Southeast Indian Ocean; insights from IODP Site U1516","authors":"Maqsood Ur Rahman , Tao Jiang , Muhammad Sarim , Qianru Wang , Cong Cheng","doi":"10.1016/j.sedgeo.2025.106930","DOIUrl":"10.1016/j.sedgeo.2025.106930","url":null,"abstract":"<div><div>The Late Quaternary is a crucial period marked by glacial-interglacial cycles that significantly impacted global paleoceanography and paleoclimate, making the reconstruction of terrigenous input in the southeastern Indian Ocean vital for understanding these shifts. We present a terrigenous sediment record from International Ocean Discovery Program Site U1516 in the offshore Mentelle Basin, reconstructing sediment provenance, transport mechanisms, and paleoclimate variability over the last 766 ky (MIS18-1). Grain-size analysis reveals a silt-dominated assemblage, with median grain size coarsening during glacial periods, reflecting enhanced winnowing of fine particles, while elevated clay concentrations suggest greater resistance to winnowing and increased supply from shallow shelves due to sea-level decline. Clay mineral assemblages show dominance of kaolinite and illite during interglacials, contrasting with peaks in smectite and chlorite during glacials. These patterns are attributed to sources in southwestern Australia transported by the Leeuwin Current, which delivered more kaolinite and illite during intensified interglacials and shifted to finer-grained smectite during weakened glacials. Elevated chlorite during glacials likely derives from deep marine settings south of Australia or Antarctica, transported via Antarctic Intermediate Water and Leeuwin Undercurrent. This variability highlights glacial-interglacial shifts in sediment routing tied to ocean circulation changes. Contrary to earlier observations of ‘dry glacials’ in southern Australia, data from Hole U1516B (illite crystallinity, chemical indices) reveal the presence of both wet and dry periods during glacials that were previously assumed to be solely dry, aligning with speleothem records but conflicting with bulk geochemical interpretations. This highlights the need for proxy-specific calibration. Interglacial periods also show intensified wetter intervals similar to those during glacials. These glacial-interglacial wetter intervals are likely driven by latitudinal shifts in the Southern Hemisphere westerly winds. This study provides new insights into glacial-interglacial transitions, linking oceanic circulation shifts, sediment transport dynamics, and hydroclimate variability in southwest Western Australia.</div></div>","PeriodicalId":21575,"journal":{"name":"Sedimentary Geology","volume":"486 ","pages":"Article 106930"},"PeriodicalIF":2.7,"publicationDate":"2025-07-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144580848","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 : 2025-07-04DOI: 10.1016/j.sedgeo.2025.106932
Hui Xie , Fei Li , Xiang Li , Jiangong Wang , Chaojin Lu , Yuefeng Shen , Yalan Li , Zengjun Wang , Tianshu Zhang , Yangfan Li , Tao Wu , Ying Li
The development of lacustrine carbonate bioherms in the Qaidam Basin provides critical insights into the influence of the Qinghai-Tibetan Plateau (QTP) uplift and climate change on Asian interior lake ecosystems. Two distinct, successively developed phases of carbonate bioherm proliferation, each extending laterally for over 3 km, have been identified within the Lower to Middle Miocene siliciclastic-dominated strata of the western Qaidam Basin, northeastern Tibetan Plateau. These bioherms exhibit diverse morphologies—ranging from large domical structures (>3 m high) to smaller hemispherical and inverted conical forms (<1 m)—and are arranged either as biostromes within a single stratigraphic level or in complex, vertically stacked patterns. Green algae (Cladophorites and problematic Chlorellopsis) and putative calcimicrobes were the primary bioherm builders. The dominant alga Cladophorites primarily formed radially branching and dense-reticular frameworks. Putative calcified filamentous and spherical microbes, acting alone or in association with green algae, formed foundational cores or substrates. These were subsequently encased by stromatolitic crusts, which aggraded iteratively from lithified microbial mats via microbially induced mineralization. The frameworks contain abundant microsparitic (4–30 μm) calcite crusts and laminated fibrous calcite cements, complemented by fringing dolomite cement crusts at the margins; these features collectively enhanced the lithification and preservation of the bioherm structures. Through multi-scale petrographic and sedimentological analysis, ten distinct lithofacies were identified within the bioherms and adjacent strata. Based on the spatial and temporal distribution of these lithofacies, a three-stage evolutionary model is proposed for the bioherms, which includes: (1) an initiation stage on littoral quartz sand bars and ooid/peloid shoals; (2) a development stage during a gradual transgression; and (3) a termination stage marked by the deposition of littoral muds or distal sublittoral silts. The proliferation of large, algal-microbial bioherms in the plateau-type Qaidam Basin required a specific set of environmental conditions: warm, fresh-to-brackish waters, sufficient accommodation space, high alkalinity, and abundant nutrients. We propose a model highlighting the integrated effects of an enhanced hydrological cycle across the QTP, catalyzed by the Miocene Climatic Optimum. The spread of these carbonate bioherms into the typically cold, arid, and saline lacustrine environments of the QTP serves as a significant indicator of this extreme warming event, providing valuable insights into potential biological and sedimentological feedback mechanisms under analogous present-day warming conditions.
{"title":"Giant lacustrine bioherms in the northeastern Qinghai-Tibet Plateau (western Qaidam Basin) during the Early–Middle Miocene: Carbonate fabrics, growth patterns, and environmental significance","authors":"Hui Xie , Fei Li , Xiang Li , Jiangong Wang , Chaojin Lu , Yuefeng Shen , Yalan Li , Zengjun Wang , Tianshu Zhang , Yangfan Li , Tao Wu , Ying Li","doi":"10.1016/j.sedgeo.2025.106932","DOIUrl":"10.1016/j.sedgeo.2025.106932","url":null,"abstract":"<div><div>The development of lacustrine carbonate bioherms in the Qaidam Basin provides critical insights into the influence of the Qinghai-Tibetan Plateau (QTP) uplift and climate change on Asian interior lake ecosystems. Two distinct, successively developed phases of carbonate bioherm proliferation, each extending laterally for over 3 km, have been identified within the Lower to Middle Miocene siliciclastic-dominated strata of the western Qaidam Basin, northeastern Tibetan Plateau. These bioherms exhibit diverse morphologies—ranging from large domical structures (>3 m high) to smaller hemispherical and inverted conical forms (<1 m)—and are arranged either as biostromes within a single stratigraphic level or in complex, vertically stacked patterns. Green algae (<em>Cladophorites</em> and problematic <em>Chlorellopsis</em>) and putative calcimicrobes were the primary bioherm builders. The dominant alga <em>Cladophorites</em> primarily formed radially branching and dense-reticular frameworks. Putative calcified filamentous and spherical microbes, acting alone or in association with green algae, formed foundational cores or substrates. These were subsequently encased by stromatolitic crusts, which aggraded iteratively from lithified microbial mats via microbially induced mineralization. The frameworks contain abundant microsparitic (4–30 μm) calcite crusts and laminated fibrous calcite cements, complemented by fringing dolomite cement crusts at the margins; these features collectively enhanced the lithification and preservation of the bioherm structures. Through multi-scale petrographic and sedimentological analysis, ten distinct lithofacies were identified within the bioherms and adjacent strata. Based on the spatial and temporal distribution of these lithofacies, a three-stage evolutionary model is proposed for the bioherms, which includes: (1) an initiation stage on littoral quartz sand bars and ooid/peloid shoals; (2) a development stage during a gradual transgression; and (3) a termination stage marked by the deposition of littoral muds or distal sublittoral silts. The proliferation of large, algal-microbial bioherms in the plateau-type Qaidam Basin required a specific set of environmental conditions: warm, fresh-to-brackish waters, sufficient accommodation space, high alkalinity, and abundant nutrients. We propose a model highlighting the integrated effects of an enhanced hydrological cycle across the QTP, catalyzed by the Miocene Climatic Optimum. The spread of these carbonate bioherms into the typically cold, arid, and saline lacustrine environments of the QTP serves as a significant indicator of this extreme warming event, providing valuable insights into potential biological and sedimentological feedback mechanisms under analogous present-day warming conditions.</div></div>","PeriodicalId":21575,"journal":{"name":"Sedimentary Geology","volume":"486 ","pages":"Article 106932"},"PeriodicalIF":2.7,"publicationDate":"2025-07-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144695180","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 : 2025-07-04DOI: 10.1016/j.sedgeo.2025.106931
Santiago Centorbi , R. Agustin Mors , Ricardo A. Astini , Fernando J. Gomez , Brenda Y. Alvarez
This study focuses on a modern tufa system developing under a semi-arid climate at mid-latitude in the Sierras Pampeanas of central Argentina, currently undergoing degradation. The research integrates a geomorphological, sedimentological, mineralogical, and hydrochemical approach to analyze constructive and destructive processes in tufa systems and their preservation potential in the stratigraphic record. The tufa features a 12.2-m-high, semi-conical structure, perched in a waterfall at the confluence of the Los Quebrachitos stream and Cabana River, overlying crystalline basement rocks rich in marble belts. The main lithofacies identified are: biohermal tufa, laminated tufa crusts, sandy tufa. Additionally, rubble tufa deposits occur at the base of the waterfall. Biohermal tufas are dominated by phytohermal components and associated invertebrate remains, with irregular clotted-micrite and peloidal fabrics. At the microscale, microbial activity becomes more significant, where cyanobacteria, diatoms, and exopolymeric substances contribute to the development of irregular laminated fabrics. Laminated tufa crusts consist of alternating micritic, microsparitic, and sparitic low-Mg calcite layers. The Los Quebrachitos stream, classified as fresh (total dissolved solids between 81.57 and 79.5 mg/L), slightly alkaline (pH between 7.9 and 8.3) waters, has a calcium-bicarbonate composition (Ca2+ between 23.10 and 26.16 mg/L, carbonate alkalinity between 95.95 and 112.18 mg/L). Flow rate variations, due to rainfall, appear to control the carbonate saturation state of waters in the Los Quebrachitos system. During dry season, the combined effects of aeration, low pressure, and jet flow enhance CO2 degassing, enabling slightly saturated conditions with respect to calcite (Ωcal = 1.1), promoting tiny water droplets evaporation, and thereby, inducing calcite precipitation. Conversely, increased rainfall dilutes water, reducing total dissolved solids and calcite saturation. Currently, the tufa system is in a destructive phase, showing gravitational collapse, bio-fracturing from tree root colonization, and surface erosion-dissolution features. The ongoing destructive processes seem to exceed the precipitation rates in this depleted carbonate system, mainly due to changes in climate conditions.
{"title":"Constructive and destructive processes affecting a tufa system in semi-arid Sierras Pampeanas, Argentina","authors":"Santiago Centorbi , R. Agustin Mors , Ricardo A. Astini , Fernando J. Gomez , Brenda Y. Alvarez","doi":"10.1016/j.sedgeo.2025.106931","DOIUrl":"10.1016/j.sedgeo.2025.106931","url":null,"abstract":"<div><div>This study focuses on a modern tufa system developing under a semi-arid climate at mid-latitude in the Sierras Pampeanas of central Argentina, currently undergoing degradation. The research integrates a geomorphological, sedimentological, mineralogical, and hydrochemical approach to analyze constructive and destructive processes in tufa systems and their preservation potential in the stratigraphic record. The tufa features a 12.2-m-high, semi-conical structure, perched in a waterfall at the confluence of the Los Quebrachitos stream and Cabana River, overlying crystalline basement rocks rich in marble belts. The main lithofacies identified are: biohermal tufa, laminated tufa crusts, sandy tufa. Additionally, rubble tufa deposits occur at the base of the waterfall. Biohermal tufas are dominated by phytohermal components and associated invertebrate remains, with irregular clotted-micrite and peloidal fabrics. At the microscale, microbial activity becomes more significant, where cyanobacteria, diatoms, and exopolymeric substances contribute to the development of irregular laminated fabrics. Laminated tufa crusts consist of alternating micritic, microsparitic, and sparitic low-Mg calcite layers. The Los Quebrachitos stream, classified as fresh (total dissolved solids between 81.57 and 79.5 mg/L), slightly alkaline (pH between 7.9 and 8.3) waters, has a calcium-bicarbonate composition (Ca<sup>2+</sup> between 23.10 and 26.16 mg/L, carbonate alkalinity between 95.95 and 112.18 mg/L). Flow rate variations, due to rainfall, appear to control the carbonate saturation state of waters in the Los Quebrachitos system. During dry season, the combined effects of aeration, low pressure, and jet flow enhance CO<sub>2</sub> degassing, enabling slightly saturated conditions with respect to calcite (Ω<sub>cal</sub> = 1.1), promoting tiny water droplets evaporation, and thereby, inducing calcite precipitation. Conversely, increased rainfall dilutes water, reducing total dissolved solids and calcite saturation. Currently, the tufa system is in a destructive phase, showing gravitational collapse, bio-fracturing from tree root colonization, and surface erosion-dissolution features. The ongoing destructive processes seem to exceed the precipitation rates in this depleted carbonate system, mainly due to changes in climate conditions.</div></div>","PeriodicalId":21575,"journal":{"name":"Sedimentary Geology","volume":"486 ","pages":"Article 106931"},"PeriodicalIF":2.7,"publicationDate":"2025-07-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144589079","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 : 2025-07-03DOI: 10.1016/j.sedgeo.2025.106933
Argel de Assis Nunes Sodré , Afonso César Rodrigues Nogueira , Juliana Charão Marques , João Vicente Tavares Calandrini de Azevedo , Renan Fernandes dos Santos , Luiz Saturnino Andrade , Leandro Freitas Sepeda , Pedro Guilherme Assunção Oliveira
Palaeolakes of the Late Jurassic, in West Gondwana, were critically shaped by thermal subsidence, driven by isostatic adjustment, isotherm downgrading, and the cooling of mafic magma associated with the Central Atlantic Magmatic Province (CAMP) around 201 Ma. These key processes are recorded in the Pastos Bons Formation, located within the Parnaíba Basin in northeastern Brazil. Although this sedimentary succession has recently been examined from a palaeoenvironmental perspective, a significant gap remains in characterizing its stacking patterns through the lens of high-resolution sequence stratigraphy (HRSS). Therefore, there remains a lack of clarity regarding the interplay between climatic and thermal subsidence and its influence on sedimentation and lake level fluctuations. Hence, we identified twenty sedimentary facies, grouped into six facies associations: central lake (FA1), hyperpycnal littoral delta (FA2), lakeshore (FA3), alluvial fan (FA4), fluvial (FA5), and delta front (FA6). The HRSS framework reveals three medium-frequency sequences, representing clusters of high-frequency T-R (transgressive-regressive) sequences, controlled by long-term climatic changes: sequence-1 (Seq-1), sequence-2 (Seq-2), and sequence-3 (Seq-3). Seq-1 and Seq-2 exhibit a higher proportion of transgressive system tract (TST) than regressive system tract (RST), and they demonstrate dramatic fluctuations in lake level. In contrast, Seq-3 shows a predominance of the regressive systems tract (RST) over the transgressive systems tract (TST), reflecting greater stability in lake level. The medium-frequency framework reveals that the Pastos Bons Formation is characterized by a balanced-fill lacustrine basin (Seq-1 and Seq-2) overlaid by an overfilled lacustrine basin (Seq-3). The low-frequency chronostratigraphic framework, composed of clusters of medium-frequency T-R sequences (seismic scale), indicates that post-CAMP thermal subsidence presents a primary control on the configuration, size, shape, and accommodation potential of the lacustrine basin. Post-CAMP subsidence along the Equatorial Atlantic margins during the Late Jurassic period played a key role in shaping the palaeogeography of West Gondwana, promoting the development of lacustrine basins.
{"title":"High-resolution sequence stratigraphy of Upper Jurassic lacustrine cycles in the Parnaíba Basin, Brazil: Unraveling basin evolution through climate and thermal subsidence","authors":"Argel de Assis Nunes Sodré , Afonso César Rodrigues Nogueira , Juliana Charão Marques , João Vicente Tavares Calandrini de Azevedo , Renan Fernandes dos Santos , Luiz Saturnino Andrade , Leandro Freitas Sepeda , Pedro Guilherme Assunção Oliveira","doi":"10.1016/j.sedgeo.2025.106933","DOIUrl":"10.1016/j.sedgeo.2025.106933","url":null,"abstract":"<div><div>Palaeolakes of the Late Jurassic, in West Gondwana, were critically shaped by thermal subsidence, driven by isostatic adjustment, isotherm downgrading, and the cooling of mafic magma associated with the Central Atlantic Magmatic Province (CAMP) around 201 Ma. These key processes are recorded in the Pastos Bons Formation, located within the Parnaíba Basin in northeastern Brazil. Although this sedimentary succession has recently been examined from a palaeoenvironmental perspective, a significant gap remains in characterizing its stacking patterns through the lens of high-resolution sequence stratigraphy (HRSS). Therefore, there remains a lack of clarity regarding the interplay between climatic and thermal subsidence and its influence on sedimentation and lake level fluctuations. Hence, we identified twenty sedimentary facies, grouped into six facies associations: central lake (FA1), hyperpycnal littoral delta (FA2), lakeshore (FA3), alluvial fan (FA4), fluvial (FA5), and delta front (FA6). The HRSS framework reveals three medium-frequency sequences, representing clusters of high-frequency T-R (transgressive-regressive) sequences, controlled by long-term climatic changes: sequence-1 (Seq-1), sequence-2 (Seq-2), and sequence-3 (Seq-3). Seq-1 and Seq-2 exhibit a higher proportion of transgressive system tract (TST) than regressive system tract (RST), and they demonstrate dramatic fluctuations in lake level. In contrast, Seq-3 shows a predominance of the regressive systems tract (RST) over the transgressive systems tract (TST), reflecting greater stability in lake level. The medium-frequency framework reveals that the Pastos Bons Formation is characterized by a balanced-fill lacustrine basin (Seq-1 and Seq-2) overlaid by an overfilled lacustrine basin (Seq-3). The low-frequency chronostratigraphic framework, composed of clusters of medium-frequency T-R sequences (seismic scale), indicates that post-CAMP thermal subsidence presents a primary control on the configuration, size, shape, and accommodation potential of the lacustrine basin. Post-CAMP subsidence along the Equatorial Atlantic margins during the Late Jurassic period played a key role in shaping the palaeogeography of West Gondwana, promoting the development of lacustrine basins.</div></div>","PeriodicalId":21575,"journal":{"name":"Sedimentary Geology","volume":"486 ","pages":"Article 106933"},"PeriodicalIF":2.7,"publicationDate":"2025-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144604350","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 : 2025-07-02DOI: 10.1016/j.sedgeo.2025.106929
Eberhard Gischler
<div><div>Surface sediment samples (<em>n</em> = 886) collected on tropical reefs and carbonate platforms in the western Atlantic, the central and eastern Indian Ocean, the south and west Pacific Ocean, and the Persian Gulf have been revisited and examined in their entirety. The samples stem from twelve depositional environments, i.e., fore reef, reef margin, sand apron, shallow lagoon, deep lagoon, restricted lagoon, patch reef, island, nearshore; inner ramp, mid ramp, and outer ramp. Grain composition, texture, mineralogy, and geochemistry have been analyzed in a quantitative and statistical manner. Fragments of coral skeletons, calcareous algae (red coralline algae, <em>Halimeda</em>), mollusk shells, and non-skeletal grains (predominantly peloids) are the most abundant constituent carbonate grains. Coralgal, grain-supported textures are common at the margins whereas mud- and grain-supported textures with mollusks, <em>Halimeda</em>, and non-skeletal grains are ubiquitous in rimmed platform interiors. Non-rimmed platforms are characterized by non-skeletal grains on the inner ramp, while mid and outer ramps are rich in mollusk shells. Multivariate statistics of composition and texture data have been used to discern fourteen facies including (1) quartz-rich marl, (2) quartz sand, (3) foraminiferal grainstone to packstone, (4) mollusk-foraminiferal grainstone to packstone, (5) mollusk grainstone to packstone, (6) non-skeletal grainstone to packstone, (7) <em>Halimeda</em> grainstone to packstone, (8) coral-rich grainstone, (9) quartz-rich biogenic grainstone, (10) mollusk packstone, (11) coral packstone, (12) non-skeletal packstone to wackestone, (13) wackestone, and (14) mudstone. There is a statistically significant correlation between the amount of fines (‘mud’) and water depth, i.e., depositional energy, however, individual facies exhibit large depth ranges, thereby underlining previous studies that have challenged intuitive and long-standing concepts of sediment distribution. An exception to this scheme is the ramp system in the northern Persian-Arabian Gulf where facies boundaries approximately follow bathymetric contours. Aragonite (83.2 ± 0.6 % relative abundance ± standard error of mean) and high-magnesium calcite (11.1 ± 0.6 %) are the most common carbonate phases reflecting skeletal mineralogy of producers. The abundance of low-magnesium calcite is lowest (5.2 ± 0.1 %). Stable isotopes of oxygen (δ<sup>18</sup>O: −3 ‰ to +3 ‰) and carbon (δ<sup>13</sup>C: −2 ‰ to +6 ‰) of bulk samples exhibit wide ranges and appear to be controlled principally by region rather than by depositional environment within reefs and carbonate platforms. Western Atlantic and south Pacific platform samples show the highest δ<sup>13</sup>C, as a consequence of the occurrence of abundant non-skeletal grains, which are largely lacking in the open Indian Ocean samples. Samples from the Persian Gulf and Shark Bay reach the highest δ<sup>18</sup>O due to elevated sal
{"title":"Sediment distribution and facies of modern tropical reefs and carbonate platforms revisited: A global perspective","authors":"Eberhard Gischler","doi":"10.1016/j.sedgeo.2025.106929","DOIUrl":"10.1016/j.sedgeo.2025.106929","url":null,"abstract":"<div><div>Surface sediment samples (<em>n</em> = 886) collected on tropical reefs and carbonate platforms in the western Atlantic, the central and eastern Indian Ocean, the south and west Pacific Ocean, and the Persian Gulf have been revisited and examined in their entirety. The samples stem from twelve depositional environments, i.e., fore reef, reef margin, sand apron, shallow lagoon, deep lagoon, restricted lagoon, patch reef, island, nearshore; inner ramp, mid ramp, and outer ramp. Grain composition, texture, mineralogy, and geochemistry have been analyzed in a quantitative and statistical manner. Fragments of coral skeletons, calcareous algae (red coralline algae, <em>Halimeda</em>), mollusk shells, and non-skeletal grains (predominantly peloids) are the most abundant constituent carbonate grains. Coralgal, grain-supported textures are common at the margins whereas mud- and grain-supported textures with mollusks, <em>Halimeda</em>, and non-skeletal grains are ubiquitous in rimmed platform interiors. Non-rimmed platforms are characterized by non-skeletal grains on the inner ramp, while mid and outer ramps are rich in mollusk shells. Multivariate statistics of composition and texture data have been used to discern fourteen facies including (1) quartz-rich marl, (2) quartz sand, (3) foraminiferal grainstone to packstone, (4) mollusk-foraminiferal grainstone to packstone, (5) mollusk grainstone to packstone, (6) non-skeletal grainstone to packstone, (7) <em>Halimeda</em> grainstone to packstone, (8) coral-rich grainstone, (9) quartz-rich biogenic grainstone, (10) mollusk packstone, (11) coral packstone, (12) non-skeletal packstone to wackestone, (13) wackestone, and (14) mudstone. There is a statistically significant correlation between the amount of fines (‘mud’) and water depth, i.e., depositional energy, however, individual facies exhibit large depth ranges, thereby underlining previous studies that have challenged intuitive and long-standing concepts of sediment distribution. An exception to this scheme is the ramp system in the northern Persian-Arabian Gulf where facies boundaries approximately follow bathymetric contours. Aragonite (83.2 ± 0.6 % relative abundance ± standard error of mean) and high-magnesium calcite (11.1 ± 0.6 %) are the most common carbonate phases reflecting skeletal mineralogy of producers. The abundance of low-magnesium calcite is lowest (5.2 ± 0.1 %). Stable isotopes of oxygen (δ<sup>18</sup>O: −3 ‰ to +3 ‰) and carbon (δ<sup>13</sup>C: −2 ‰ to +6 ‰) of bulk samples exhibit wide ranges and appear to be controlled principally by region rather than by depositional environment within reefs and carbonate platforms. Western Atlantic and south Pacific platform samples show the highest δ<sup>13</sup>C, as a consequence of the occurrence of abundant non-skeletal grains, which are largely lacking in the open Indian Ocean samples. Samples from the Persian Gulf and Shark Bay reach the highest δ<sup>18</sup>O due to elevated sal","PeriodicalId":21575,"journal":{"name":"Sedimentary Geology","volume":"486 ","pages":"Article 106929"},"PeriodicalIF":2.7,"publicationDate":"2025-07-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144556625","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 : 2025-06-22DOI: 10.1016/j.sedgeo.2025.106927
Zhiying Dang , Yulin Shen , Zuchao Wen , Zhuangfu Li , Feiyang Chen , Yan Meng , Tianyang Yang , Yuhong Jing
The lack of high-precision age constraints for the internal age of the Cambrian in North China has always affected the research and comparison of Cambrian strata worldwide. This study, using magnetic susceptibility data from the Cambrian strata of the Xuzhou area, identifies Milankovitch cycles within the sedimentary strata. By utilizing stable carbon isotope excursion curves, the lower Furongian in the study area was discerned to exhibit a Steptoean positive carbon isotope excursion (SPICE) event, lasting ∼1.6–1.8 Myr, with a peak age constrained to 494.6 ± 2.9 Ma. Using in situ RbSr dating from glauconite grains in the base of the Mantou Formation (Stage 4), the stratigraphic age was constrained to about 513 Ma. By anchoring the identified 405-kyr calibration time series to these two ages, a relatively high-resolution astronomical time scale was constructed. The results indicate that the Cambrian Stage 4 to early Stage 10 in the Xuzhou area of North China spans from 512.30 ± 2.9 Ma to 490.03 ± 2.9 Ma, with a duration of 22.27 ± 0.2 Myr. Specifically, the basal ages of the Mantou Formation (Series 2 to Miaolingian Series; Stage 4 to early Drumian stage), Zhangxia Formation (Miaolingian to Furongian Series; early Drumian to middle Paibian stage), and Chaomidian Formation (Furongian Series; middle Paibian to early Stage 10) were determined to be 512.30 ± 2.9 Ma, 504.00 ± 2.9 Ma, and 495.74 ± 2.9 Ma, respectively, with durations of 8.30 ± 0.2 Myr, 8.26 ± 0.2 Myr, and 5.71 ± 0.2 Myr. This series of studies not only standardized the classification of lithostratigraphic units in the Xuzhou area, but also provided precise chronological evidence for exploring the climatic-biota-environmental ecological evolution during the Cambrian period.
{"title":"Astronomical time scale and stratigraphic division constrained by the Milankovitch cycles and SPICE event in the Cambrian of the Xuzhou, Jiangsu Province","authors":"Zhiying Dang , Yulin Shen , Zuchao Wen , Zhuangfu Li , Feiyang Chen , Yan Meng , Tianyang Yang , Yuhong Jing","doi":"10.1016/j.sedgeo.2025.106927","DOIUrl":"10.1016/j.sedgeo.2025.106927","url":null,"abstract":"<div><div>The lack of high-precision age constraints for the internal age of the Cambrian in North China has always affected the research and comparison of Cambrian strata worldwide. This study, using magnetic susceptibility data from the Cambrian strata of the Xuzhou area, identifies Milankovitch cycles within the sedimentary strata. By utilizing stable carbon isotope excursion curves, the lower Furongian in the study area was discerned to exhibit a Steptoean positive carbon isotope excursion (SPICE) event, lasting ∼1.6–1.8 Myr, with a peak age constrained to 494.6 ± 2.9 Ma. Using in situ Rb<img>Sr dating from glauconite grains in the base of the Mantou Formation (Stage 4), the stratigraphic age was constrained to about 513 Ma. By anchoring the identified 405-kyr calibration time series to these two ages, a relatively high-resolution astronomical time scale was constructed. The results indicate that the Cambrian Stage 4 to early Stage 10 in the Xuzhou area of North China spans from 512.30 ± 2.9 Ma to 490.03 ± 2.9 Ma, with a duration of 22.27 ± 0.2 Myr. Specifically, the basal ages of the Mantou Formation (Series 2 to Miaolingian Series; Stage 4 to early Drumian stage), Zhangxia Formation (Miaolingian to Furongian Series; early Drumian to middle Paibian stage), and Chaomidian Formation (Furongian Series; middle Paibian to early Stage 10) were determined to be 512.30 ± 2.9 Ma, 504.00 ± 2.9 Ma, and 495.74 ± 2.9 Ma, respectively, with durations of 8.30 ± 0.2 Myr, 8.26 ± 0.2 Myr, and 5.71 ± 0.2 Myr. This series of studies not only standardized the classification of lithostratigraphic units in the Xuzhou area, but also provided precise chronological evidence for exploring the climatic-biota-environmental ecological evolution during the Cambrian period.</div></div>","PeriodicalId":21575,"journal":{"name":"Sedimentary Geology","volume":"486 ","pages":"Article 106927"},"PeriodicalIF":2.7,"publicationDate":"2025-06-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144501669","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 : 2025-06-22DOI: 10.1016/j.sedgeo.2025.106926
Xiaocan Yu , Chunlian Wang , Gabriel Bertolini , Claiton Marlon dos Santos Scherer , Adriano Domingos dos Reis , Nigel P. Mountney
The Upper Cretaceous Daijiaping Formation of the Chaling Basin, southeast China, is a mixed aeolian–fluvial succession accumulated in an erg-margin setting. The roles of climate and tectonics in governing the temporal and spatial arrangement of aeolian and fluvial strata are investigated using lithofacies and architectural-element analyses of outcrops in the eastern part of the basin. Architectural elements of aeolian origin record the preserved expression of dunes, sandsheets, damp and wet interdunes, and sand pods. Architectural elements of alluvial origin record channelized bedload streams and cobble-sand sheetflow units. Distinctive deflation lags and desert pavements are also recognized. The alternating nature of deposition via aeolian and aqueous processes is marked by a series of sand-drift surfaces that form a record of repeated shifts from aeolian to water-lain depositional conditions. Ephemeral water influx to the desert-margin system likely occurred in response to exceptional rainfall caused by monsoonal water discharge and meltwaters from glaciated mountain ranges that bordered the basin. The vertical arrangements of alternating facies associations define stacked wetting-upward cycles, each 0.4–14.2 m thick. Each cycle commences with simple or compound crescentic dune deposits, else with aeolian sandsheet deposits. These are overlain by bedload stream or conglomerate sheetflow deposits. The vertical stacking of these different architectural elements records the contraction and expansion of erg-margin systems in response to climate-controlled variations in the groundwater level, sand availability for aeolian transport, and fluvial and aeolian sediment transport capacity. The stratigraphic evolution was controlled by exceptional rainfall events at the basin margin, consequent floods into the dune-field margin and associated fluctuations in the water-table level. Orogenic uplift, a subtropical high-pressure system, and a variable groundwater level controlled by a monsoon climate and tectonic subsidence resulted in the development of extensive aeolian desert depositional systems in the South China hinterland during the Late Cretaceous.
{"title":"Aeolian–fluvial interactions within a fault-controlled basin: Late Cretaceous Chaling Basin, South China","authors":"Xiaocan Yu , Chunlian Wang , Gabriel Bertolini , Claiton Marlon dos Santos Scherer , Adriano Domingos dos Reis , Nigel P. Mountney","doi":"10.1016/j.sedgeo.2025.106926","DOIUrl":"10.1016/j.sedgeo.2025.106926","url":null,"abstract":"<div><div>The Upper Cretaceous Daijiaping Formation of the Chaling Basin, southeast China, is a mixed aeolian–fluvial succession accumulated in an erg-margin setting. The roles of climate and tectonics in governing the temporal and spatial arrangement of aeolian and fluvial strata are investigated using lithofacies and architectural-element analyses of outcrops in the eastern part of the basin. Architectural elements of aeolian origin record the preserved expression of dunes, sandsheets, damp and wet interdunes, and sand pods. Architectural elements of alluvial origin record channelized bedload streams and cobble-sand sheetflow units. Distinctive deflation lags and desert pavements are also recognized. The alternating nature of deposition via aeolian and aqueous processes is marked by a series of sand-drift surfaces that form a record of repeated shifts from aeolian to water-lain depositional conditions. Ephemeral water influx to the desert-margin system likely occurred in response to exceptional rainfall caused by monsoonal water discharge and meltwaters from glaciated mountain ranges that bordered the basin. The vertical arrangements of alternating facies associations define stacked wetting-upward cycles, each 0.4–14.2 m thick. Each cycle commences with simple or compound crescentic dune deposits, else with aeolian sandsheet deposits. These are overlain by bedload stream or conglomerate sheetflow deposits. The vertical stacking of these different architectural elements records the contraction and expansion of erg-margin systems in response to climate-controlled variations in the groundwater level, sand availability for aeolian transport, and fluvial and aeolian sediment transport capacity. The stratigraphic evolution was controlled by exceptional rainfall events at the basin margin, consequent floods into the dune-field margin and associated fluctuations in the water-table level. Orogenic uplift, a subtropical high-pressure system, and a variable groundwater level controlled by a monsoon climate and tectonic subsidence resulted in the development of extensive aeolian desert depositional systems in the South China hinterland during the Late Cretaceous.</div></div>","PeriodicalId":21575,"journal":{"name":"Sedimentary Geology","volume":"486 ","pages":"Article 106926"},"PeriodicalIF":2.7,"publicationDate":"2025-06-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144518052","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 : 2025-06-20DOI: 10.1016/j.sedgeo.2025.106925
Javier Elorza , Clemente Recio
Isolated beachrocks appear as relict patches normally attached to protrusions of lower-upper Cretaceous limestones outcropping at Noja, Somo and Sonabia zones in the eastern coast of Cantabria (northern Spain). Additionally, remnant cemented dunes (eolianites) are present at different heights above present sea level. We concentrate on the petrographic features of first-generation cements, that are different in the lower foreshore and upper foreshore-backshore. δ13C and δ18O values measured in the cements of both beachrock and eolianite suggest mixing between marine and meteoric waters, generally with preponderance of the continental contribution. In all the studied examples, Coccus-type bacterial activity has been recognized, suggesting that it is the main trigger for the initiation of cementation. 14C dating shows that the different cementations studied did not occur in a single event at a specific age, since there is a notable variation, from the highest values of 8760 years BP to 2740 years BP, despite the beachrock patches being at the height of the current intertidal zone. In the non-cemented intertidal sands that form the current beaches there are also important variations, difficult to justify, from similar ages of 3050 years BP (Noja) and 3010 years BP (Somo) to a mere 390 years BP (Sonabia).
{"title":"Residual beachrock and coastal eolianite patches without anthropogenic components on the eastern coast of Cantabria (Spain)","authors":"Javier Elorza , Clemente Recio","doi":"10.1016/j.sedgeo.2025.106925","DOIUrl":"10.1016/j.sedgeo.2025.106925","url":null,"abstract":"<div><div>Isolated beachrocks appear as relict patches normally attached to protrusions of lower-upper Cretaceous limestones outcropping at Noja, Somo and Sonabia zones in the eastern coast of Cantabria (northern Spain). Additionally, remnant cemented dunes (eolianites) are present at different heights above present sea level. We concentrate on the petrographic features of first-generation cements, that are different in the lower foreshore and upper foreshore-backshore. δ<sup>13</sup>C and δ<sup>18</sup>O values measured in the cements of both beachrock and eolianite suggest mixing between marine and meteoric waters, generally with preponderance of the continental contribution. In all the studied examples, <em>Coccus</em>-type bacterial activity has been recognized, suggesting that it is the main trigger for the initiation of cementation. <sup>14</sup>C dating shows that the different cementations studied did not occur in a single event at a specific age, since there is a notable variation, from the highest values of 8760 years BP to 2740 years BP, despite the beachrock patches being at the height of the current intertidal zone. In the non-cemented intertidal sands that form the current beaches there are also important variations, difficult to justify, from similar ages of 3050 years BP (Noja) and 3010 years BP (Somo) to a mere 390 years BP (Sonabia).</div></div>","PeriodicalId":21575,"journal":{"name":"Sedimentary Geology","volume":"486 ","pages":"Article 106925"},"PeriodicalIF":2.7,"publicationDate":"2025-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144580846","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 : 2025-06-18DOI: 10.1016/j.sedgeo.2025.106924
Francesco Perri , Sara Criniti , Francesco Cavalcante , Manuel Martín-Martín , Antonio Sánchez-Navas , Salvatore Critelli
The Sierra Espuña and the Mula-Gebas intramontane basin, SE Spain, represent the Internal-External Zone Boundary (IEZB) of the eastern Betic Cordillera. The Miocene infill of this basin seals the IEZB and is mainly derived from the Internal Zone. This deposition is coeval with a Late Miocene volcanism. Therefore, the study of these sediments is crucial for the source-area provenance, sorting and recycling, paleoclimate, weathering, unroofing and tectonic processes, during the intramontane basins developing of the western peri-Mediterranean Chains. Sandstone detrital modes, and mineralogical and chemical compositions of mudrocks were arranged in two sedimentary cycles: (1) the middle Burdigalian-early Langhian, and (2) the middle Tortonian-early Messinian. The quartzolithic to feldspathic lithoarenites infer the erosion from a lithic-transitional recycled to transitional-quartzose recycled orogen, since low-medium grade metamorphic lithics and rare coeval volcanics with andesitic, andesitic-dacitic and rhyodacitic-rhyolitic sources are present. The mudrocks reveal a felsic (granitic-gneiss) source with a minor mafic input in the Upper Miocene. A shallow burial history and low thermal conditions (<∼50 °C) has been also evidenced. Moreover, the paleoclimate changed from warm and/or wet during the Middle Miocene to cold/arid in the Late Miocene.
{"title":"The Miocene sedimentary cover of the Mula-Gebas Basin: Internal-External Zone Boundary of the Betic Cordillera, South Spain","authors":"Francesco Perri , Sara Criniti , Francesco Cavalcante , Manuel Martín-Martín , Antonio Sánchez-Navas , Salvatore Critelli","doi":"10.1016/j.sedgeo.2025.106924","DOIUrl":"10.1016/j.sedgeo.2025.106924","url":null,"abstract":"<div><div>The Sierra Espuña and the Mula-Gebas intramontane basin, SE Spain, represent the Internal-External Zone Boundary (IEZB) of the eastern Betic Cordillera. The Miocene infill of this basin seals the IEZB and is mainly derived from the Internal Zone. This deposition is coeval with a Late Miocene volcanism. Therefore, the study of these sediments is crucial for the source-area provenance, sorting and recycling, paleoclimate, weathering, unroofing and tectonic processes, during the intramontane basins developing of the western peri-Mediterranean Chains. Sandstone detrital modes, and mineralogical and chemical compositions of mudrocks were arranged in two sedimentary cycles: (1) the middle Burdigalian-early Langhian, and (2) the middle Tortonian-early Messinian. The quartzolithic to feldspathic lithoarenites infer the erosion from a lithic-transitional recycled to transitional-quartzose recycled orogen, since low-medium grade metamorphic lithics and rare coeval volcanics with andesitic, andesitic-dacitic and rhyodacitic-rhyolitic sources are present. The mudrocks reveal a felsic (granitic-gneiss) source with a minor mafic input in the Upper Miocene. A shallow burial history and low thermal conditions (<∼50 °C) has been also evidenced. Moreover, the paleoclimate changed from warm and/or wet during the Middle Miocene to cold/arid in the Late Miocene.</div></div>","PeriodicalId":21575,"journal":{"name":"Sedimentary Geology","volume":"486 ","pages":"Article 106924"},"PeriodicalIF":2.7,"publicationDate":"2025-06-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144338611","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}
Recent studies on Early Eocene climate have established that global climatic warming, characterized by negative carbon isotopic excursions (CIE, hyperthermals) in the atmosphere, are responsible for drastically changes in the terrestrial sedimentary record of sub-tropical basins. Here we present a key sedimentary record to understand geological and climatological changes in order to evaluate the impact of hyperthermals on sediment transport and deposition in continental setting during the Early Eocene Climatic Optimum (EECO) in Europe. Based on an integrative study combining sedimentology, sequential stratigraphy, magnetostratigraphy and chemostratigraphy (carbon isotopes, δ13Corg), the study proposes a detailed constrained chronostratigraphic framework of continental sedimentary series of the Minervois Basin (South of France). Using facies association analysis, the sedimentary succession is divided into three continental sequences bounded by subaerial unconformity deposited through the development of an endoreic underfilled basin. The sequences are composed of floodplain to palustrine-shallow lacustrine carbonate deposits reflecting arid climatic conditions during the EECO. They are cyclically punctuated by the sudden arrival of detrital fluxes with deposits of supercritical bedforms associated to an ephemeral multistorey braided channel plain, reflecting intense and extreme rainfall events in the hinterland. The latter coincides to CIEs corresponding to hyperthermals identified as C24n.1nH1/K (ETM3), C23rH2 (M), and C23n.2nH1-C23n.2nH2 (NO) interval. Extreme monsoon-type events triggered by intense warm-ups during hyperthermals are proposed to explain sudden detrital inputs in the basin. This work confirms that transient hyperthermals can generate drastic hydrological changes in the sedimentary record.
{"title":"Abrupt changes in continental sedimentation triggered by monsoon-type event during EECO hyperthermals, Minervois Basin, Southern France","authors":"Cindy BOYRIE , Flavia GIRARD , Johan YANS , Grégory BALLAS , Fabrice LIHOREAU , Mouloud BENAMMI , Hélène BOURGET , Géraldine GARCIA , Christine LEREDDE , Aimée PELLISSIER-TANON , Xavier VALENTIN , Dominique VIDALENC , Rodolphe TABUCE","doi":"10.1016/j.sedgeo.2025.106923","DOIUrl":"10.1016/j.sedgeo.2025.106923","url":null,"abstract":"<div><div>Recent studies on Early Eocene climate have established that global climatic warming, characterized by negative carbon isotopic excursions (CIE, hyperthermals) in the atmosphere, are responsible for drastically changes in the terrestrial sedimentary record of sub-tropical basins. Here we present a key sedimentary record to understand geological and climatological changes in order to evaluate the impact of hyperthermals on sediment transport and deposition in continental setting during the Early Eocene Climatic Optimum (EECO) in Europe. Based on an integrative study combining sedimentology, sequential stratigraphy, magnetostratigraphy and chemostratigraphy (carbon isotopes, δ<sup>13</sup>C<sub>org</sub>), the study proposes a detailed constrained chronostratigraphic framework of continental sedimentary series of the Minervois Basin (South of France). Using facies association analysis, the sedimentary succession is divided into three continental sequences bounded by subaerial unconformity deposited through the development of an endoreic underfilled basin. The sequences are composed of floodplain to palustrine-shallow lacustrine carbonate deposits reflecting arid climatic conditions during the EECO. They are cyclically punctuated by the sudden arrival of detrital fluxes with deposits of supercritical bedforms associated to an ephemeral multistorey braided channel plain, reflecting intense and extreme rainfall events in the hinterland. The latter coincides to CIEs corresponding to hyperthermals identified as C24n.1nH1/K (ETM3), C23rH2 (M), and C23n.2nH1-C23n.2nH2 (N<img>O) interval. Extreme monsoon-type events triggered by intense warm-ups during hyperthermals are proposed to explain sudden detrital inputs in the basin. This work confirms that transient hyperthermals can generate drastic hydrological changes in the sedimentary record.</div></div>","PeriodicalId":21575,"journal":{"name":"Sedimentary Geology","volume":"486 ","pages":"Article 106923"},"PeriodicalIF":2.7,"publicationDate":"2025-06-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144518051","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}
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