Shoreface deposits are usually associated with high-energy sedimentary structures, as well as with erosional surfaces produced by waves and currents that may have sequence stratigraphic or sedimentological significance. Typical sequence stratigraphic surfaces associated with shoreface deposits are the ravinement surface (RS), the maximum flooding surface (MFS), the basal surface of forced regression (BSFR), the regressive surface of marine erosion (RSME), the subaerial unconformity (SU) and the correlative conformity (CC). However, some of these surfaces, such as the MFS, the BSFR and the CC can be cryptic and difficult to pinpoint in outcrops and cores. Facies contacts in the shoreface are represented by the local flooding surface (LFS), the downlap surface (DLS), the surf diastem (SD) and bedset boundaries (BB), which are usually well recognizable. All downstream-controlled systems tracts may form in shoreface deposits, including the lowstand systems tract (LST), transgressive systems tract (TST), highstand systems tract (HST) and falling-stage systems tract (FSST). Among these systems tracts, TSTs and HSTs are most commonly recognized. A challenge in these settings is the distinction between HSTs, FSSTs and LSTs, due to the more subtle physical expression of the BSFR and the CC in fully shoreface successions. Sequence stratigraphic surfaces and facies contacts can be identified on the basis of several criteria, including sedimentological, ichnological, diagenetic, mineralogic, geophysical, and micropaleontological. Due to their easy recognition with all kinds of data, RSs are commonly chosen as boundaries of stratigraphic sequences composed of shoreface or mixed shoreface-shelf deposits, commonly referred to as transgressive-regressive (T-R) sequences.
{"title":"Sequence stratigraphy of wave-dominated and wave-influenced shoreface deposits: Systems tracts, stratigraphic surfaces and facies contacts","authors":"Massimo Zecchin , Octavian Catuneanu , Mauro Caffau","doi":"10.1016/j.sedgeo.2025.106980","DOIUrl":"10.1016/j.sedgeo.2025.106980","url":null,"abstract":"<div><div>Shoreface deposits are usually associated with high-energy sedimentary structures, as well as with erosional surfaces produced by waves and currents that may have sequence stratigraphic or sedimentological significance. Typical sequence stratigraphic surfaces associated with shoreface deposits are the ravinement surface (RS), the maximum flooding surface (MFS), the basal surface of forced regression (BSFR), the regressive surface of marine erosion (RSME), the subaerial unconformity (SU) and the correlative conformity (CC). However, some of these surfaces, such as the MFS, the BSFR and the CC can be cryptic and difficult to pinpoint in outcrops and cores. Facies contacts in the shoreface are represented by the local flooding surface (LFS), the downlap surface (DLS), the surf diastem (SD) and bedset boundaries (BB), which are usually well recognizable. All downstream-controlled systems tracts may form in shoreface deposits, including the lowstand systems tract (LST), transgressive systems tract (TST), highstand systems tract (HST) and falling-stage systems tract (FSST). Among these systems tracts, TSTs and HSTs are most commonly recognized. A challenge in these settings is the distinction between HSTs, FSSTs and LSTs, due to the more subtle physical expression of the BSFR and the CC in fully shoreface successions. Sequence stratigraphic surfaces and facies contacts can be identified on the basis of several criteria, including sedimentological, ichnological, diagenetic, mineralogic, geophysical, and micropaleontological. Due to their easy recognition with all kinds of data, RSs are commonly chosen as boundaries of stratigraphic sequences composed of shoreface or mixed shoreface-shelf deposits, commonly referred to as transgressive-regressive (T-R) sequences.</div></div>","PeriodicalId":21575,"journal":{"name":"Sedimentary Geology","volume":"489 ","pages":"Article 106980"},"PeriodicalIF":2.9,"publicationDate":"2025-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145160146","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 : 2025-09-19DOI: 10.1016/j.sedgeo.2025.106979
Arman Jafarian , Antun Husinec , Rute Coimbra , Adrian Immenhauser , Umid Kakemem , Clemens V. Ullmann , Meng Wang , Abdus Saboor , Chengshan Wang
Marine carbonate archives in transitional coastal-to-basin settings are susceptible to syn- and post-depositional alteration, a feature that complicates the interpretation of primary environmental signals encoded in the sedimentary archive at the time of deposition. This study utilises Principal Component Analysis (PCA) to elucidate the intricate relationships between facies types, environmental controls, and the sediments' respective diagenetic susceptibilities to geochemical resetting within lower Aptian carbonates of the Kazhdumi Intrashelf Basin (Zagros Basin, Iran). The focus is on proximal mid-ramp to intrashelf-basin carbonates. Integrating facies analysis, petrography, geochemistry, and PCA, the following outcomes result: (i) Proximal facies exhibit higher Mn/Ca and lower Sr/Ca ratios linked to enhanced fluid-rock interactions and terrigenous input. Marine δ13C values and elevated Sr/Ca ratios are more pronounced in distal facies. (ii) Bulk isotope values from distal carbonates are characterised by enriched δ13C and depleted δ18O values. This suggests increased marine productivity in cooler waters and intermittently anoxic-suboxic conditions. (iii) In shallower, warmer, and well‑oxygenated proximal mid-ramp waters, reduced organic carbon burial, isotopically light carbon from terrestrial sources and the oxidation of organic matter result in lowered δ13C and higher δ18O values. The study demonstrates that despite complex diagenetic overprint, marine proxy signals remain discernible. Supported by microfacies data, PCA reveals a multi-faceted system that drives geochemical variability within a facies/bathymetric context. This outcome emphasises the critical importance of detailed facies analysis and geochemical profiling in reconstructing palaeoenvironmental conditions.
{"title":"Principal component analysis reveals the relationship between carbonate facies, geochemical properties, and diagenetic overprint","authors":"Arman Jafarian , Antun Husinec , Rute Coimbra , Adrian Immenhauser , Umid Kakemem , Clemens V. Ullmann , Meng Wang , Abdus Saboor , Chengshan Wang","doi":"10.1016/j.sedgeo.2025.106979","DOIUrl":"10.1016/j.sedgeo.2025.106979","url":null,"abstract":"<div><div>Marine carbonate archives in transitional coastal-to-basin settings are susceptible to syn- and post-depositional alteration, a feature that complicates the interpretation of primary environmental signals encoded in the sedimentary archive at the time of deposition. This study utilises Principal Component Analysis (PCA) to elucidate the intricate relationships between facies types, environmental controls, and the sediments' respective diagenetic susceptibilities to geochemical resetting within lower Aptian carbonates of the Kazhdumi Intrashelf Basin (Zagros Basin, Iran). The focus is on proximal mid-ramp to intrashelf-basin carbonates. Integrating facies analysis, petrography, geochemistry, and PCA, the following outcomes result: (i) Proximal facies exhibit higher Mn/Ca and lower Sr/Ca ratios linked to enhanced fluid-rock interactions and terrigenous input. Marine δ<sup>13</sup>C values and elevated Sr/Ca ratios are more pronounced in distal facies. (ii) Bulk isotope values from distal carbonates are characterised by enriched δ<sup>13</sup>C and depleted δ<sup>18</sup>O values. This suggests increased marine productivity in cooler waters and intermittently anoxic-suboxic conditions. (iii) In shallower, warmer, and well‑oxygenated proximal mid-ramp waters, reduced organic carbon burial, isotopically light carbon from terrestrial sources and the oxidation of organic matter result in lowered δ<sup>13</sup>C and higher δ<sup>18</sup>O values. The study demonstrates that despite complex diagenetic overprint, marine proxy signals remain discernible. Supported by microfacies data, PCA reveals a multi-faceted system that drives geochemical variability within a facies/bathymetric context. This outcome emphasises the critical importance of detailed facies analysis and geochemical profiling in reconstructing palaeoenvironmental conditions.</div></div>","PeriodicalId":21575,"journal":{"name":"Sedimentary Geology","volume":"489 ","pages":"Article 106979"},"PeriodicalIF":2.9,"publicationDate":"2025-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145221751","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 : 2025-09-04DOI: 10.1016/j.sedgeo.2025.106960
Enrico Nallino , Francesco Dela Pierre , Nicolò Zanellato , Luca Pellegrino , Daniel Birgel , Irene Cornacchia , Andrea Cotellucci , Marcello Natalicchio
Large and deep marine evaporitic basins (salt giants) are common in the geological record, but the reconstruction of the palaeoenvironment is challenging. The sedimentary products consist of clastic evaporites (mass transport and turbiditic deposits), commonly interbedded with evaporitic cumulates or non-evaporitic fine-grained deposits representing the background hemipelagic sedimentation. The study of the hemipelagic component can provide crucial palaeoenvironmental information on these basins. This study examines the non-evaporitic, hemipelagic sediments interbedded with gypsum turbidites from the Belice Basin (Italy), a deep onshore basin of the Late Miocene Mediterranean salt giant. The studied succession belongs to the Resedimented Lower Gypsum unit, formed during the second phase of the Messinian Salinity Crisis (5.60–5.55 Ma) and consists of laminated diatomaceous and organic-rich shales, dolomitic and aragonitic mudstones. Sedimentological, petrographic, and geochemical analyses indicate that the hemipelagites accumulated in a rather deep basin, with high primary productivity in superficial waters. The palaeoenvironmental conditions in the water column and at the seafloor were governed by the balance between the inflows of freshwater and marine water. Intervals of reduced continental runoff and enhanced marine ingression, which induced water column mixing and seafloor oxygenation, are recorded by the diatomaceous shales. The other lithologies record prolonged stratification of the water column, induced by riverine runoff and basin restriction. Seafloor anoxia and the input of terrestrial and marine organic matter favoured the formation of dolomite and pyrite following bacterial sulphate reduction. This study provides insights into the chemical, physical, and biological conditions in a deep basin during the Messinian Salinity Crisis.
{"title":"Reconstructing the palaeoenvironment of a deep onshore basin of the Late Miocene Mediterranean salt giant (Belice basin, Italy): Insights from hemipelagic deposits interbedded with clastic evaporites","authors":"Enrico Nallino , Francesco Dela Pierre , Nicolò Zanellato , Luca Pellegrino , Daniel Birgel , Irene Cornacchia , Andrea Cotellucci , Marcello Natalicchio","doi":"10.1016/j.sedgeo.2025.106960","DOIUrl":"10.1016/j.sedgeo.2025.106960","url":null,"abstract":"<div><div>Large and deep marine evaporitic basins (salt giants) are common in the geological record, but the reconstruction of the palaeoenvironment is challenging. The sedimentary products consist of clastic evaporites (mass transport and turbiditic deposits), commonly interbedded with evaporitic cumulates or non-evaporitic fine-grained deposits representing the background hemipelagic sedimentation. The study of the hemipelagic component can provide crucial palaeoenvironmental information on these basins. This study examines the non-evaporitic, hemipelagic sediments interbedded with gypsum turbidites from the Belice Basin (Italy), a deep onshore basin of the Late Miocene Mediterranean salt giant. The studied succession belongs to the Resedimented Lower Gypsum unit, formed during the second phase of the Messinian Salinity Crisis (5.60–5.55 Ma) and consists of laminated diatomaceous and organic-rich shales, dolomitic and aragonitic mudstones. Sedimentological, petrographic, and geochemical analyses indicate that the hemipelagites accumulated in a rather deep basin, with high primary productivity in superficial waters. The palaeoenvironmental conditions in the water column and at the seafloor were governed by the balance between the inflows of freshwater and marine water. Intervals of reduced continental runoff and enhanced marine ingression, which induced water column mixing and seafloor oxygenation, are recorded by the diatomaceous shales. The other lithologies record prolonged stratification of the water column, induced by riverine runoff and basin restriction. Seafloor anoxia and the input of terrestrial and marine organic matter favoured the formation of dolomite and pyrite following bacterial sulphate reduction. This study provides insights into the chemical, physical, and biological conditions in a deep basin during the Messinian Salinity Crisis.</div></div>","PeriodicalId":21575,"journal":{"name":"Sedimentary Geology","volume":"489 ","pages":"Article 106960"},"PeriodicalIF":2.9,"publicationDate":"2025-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145097825","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 : 2025-09-04DOI: 10.1016/j.sedgeo.2025.106961
Zhibo Yang , Hancheng Ji , Yanqing Shi , Ting Liang , Zhidong Bao
<div><div>The late Ediacaran ocean witnessed a critical phase in the evolution of early life, during which redox conditions were closely linked to biological innovation. Nevertheless, the nature of these redox conditions and their interactions with evolving ecosystems remain debated. This study provides a systematic investigation of the petrographic and geochemical characteristics of microbial dolostones from the Dengying Formation on the Yangtze Platform, South China. The results reveal that microbial dolomites in this unit comprise a diverse suite of lithofacies—bioclastic, stromatolitic, oncoidal, foam-spongy, and thrombolitic dolomites—indicative of intertidal to subtidal depositional settings. Microbialite components are classified into microbial matrix, fibrous dolomite cements, and clear equant dolomite cements. Among these, Fibrous dolomite is particularly well-developed, and its cathodoluminescence zoning and length-slow optical properties suggest <em>syn</em>-depositional precipitation during early diagenesis. Combined δ<sup>13</sup>C and <sup>87</sup>Sr/<sup>86</sup>Sr data suggest a warm and humid climate with high primary productivity and intense continental weathering during the Z<sub>2</sub>dn<sup>2</sup> interval, followed by a decline in sedimentation rates during Z<sub>2</sub>dn<sup>4</sup>, albeit with continued robust carbonate deposition. All dolomite components exhibit distinct negative cerium anomalies (Ce/Ce* < 1), heavy rare earth elements (HREEs) enrichment, and elevated Y/Ho ratios, collectively indicating deposition under well‑oxygenated shallow marine conditions. Notably, the fibrous dolomite component displays the most pronounced oxidative signature, with oxygen levels at the sediment–water interface potentially approaching atmospheric values. In contrast, the clear equant dolomite cements components reflect suboxic to weakly oxic conditions, suggesting a stratified redox water column during the late Ediacaran. These observations imply that localized oxygen-rich zones on the seafloor may have developed through microbial oxygen production. When compared across the entire Ediacaran, the widespread microbial dolomites of the Dengying Formation and their associated oxic conditions likely provided key ecological niches for early benthic metazoans, such as bilaterians. The oxygenation process recorded in this formation may have played an important role in setting the stage for the Cambrian Explosion. The Dengying Formation thus captures a significant shallow-marine oxygenation event closely associated with algal proliferation and the emergence of multicellular life, underscoring the role of biologically mediated environmental feedbacks during the terminal Neoproterozoic. This study enhances our understanding of the interplay between seawater redox structure and microbial activity at the close of the Ediacaran, and supports the interpretation that microbial metabolism may have been a key regulatory mechanism in the devel
{"title":"Redox stratification and ecological implications of microbial dolomites in the late Ediacaran Dengying Formation, Yangtze platform","authors":"Zhibo Yang , Hancheng Ji , Yanqing Shi , Ting Liang , Zhidong Bao","doi":"10.1016/j.sedgeo.2025.106961","DOIUrl":"10.1016/j.sedgeo.2025.106961","url":null,"abstract":"<div><div>The late Ediacaran ocean witnessed a critical phase in the evolution of early life, during which redox conditions were closely linked to biological innovation. Nevertheless, the nature of these redox conditions and their interactions with evolving ecosystems remain debated. This study provides a systematic investigation of the petrographic and geochemical characteristics of microbial dolostones from the Dengying Formation on the Yangtze Platform, South China. The results reveal that microbial dolomites in this unit comprise a diverse suite of lithofacies—bioclastic, stromatolitic, oncoidal, foam-spongy, and thrombolitic dolomites—indicative of intertidal to subtidal depositional settings. Microbialite components are classified into microbial matrix, fibrous dolomite cements, and clear equant dolomite cements. Among these, Fibrous dolomite is particularly well-developed, and its cathodoluminescence zoning and length-slow optical properties suggest <em>syn</em>-depositional precipitation during early diagenesis. Combined δ<sup>13</sup>C and <sup>87</sup>Sr/<sup>86</sup>Sr data suggest a warm and humid climate with high primary productivity and intense continental weathering during the Z<sub>2</sub>dn<sup>2</sup> interval, followed by a decline in sedimentation rates during Z<sub>2</sub>dn<sup>4</sup>, albeit with continued robust carbonate deposition. All dolomite components exhibit distinct negative cerium anomalies (Ce/Ce* < 1), heavy rare earth elements (HREEs) enrichment, and elevated Y/Ho ratios, collectively indicating deposition under well‑oxygenated shallow marine conditions. Notably, the fibrous dolomite component displays the most pronounced oxidative signature, with oxygen levels at the sediment–water interface potentially approaching atmospheric values. In contrast, the clear equant dolomite cements components reflect suboxic to weakly oxic conditions, suggesting a stratified redox water column during the late Ediacaran. These observations imply that localized oxygen-rich zones on the seafloor may have developed through microbial oxygen production. When compared across the entire Ediacaran, the widespread microbial dolomites of the Dengying Formation and their associated oxic conditions likely provided key ecological niches for early benthic metazoans, such as bilaterians. The oxygenation process recorded in this formation may have played an important role in setting the stage for the Cambrian Explosion. The Dengying Formation thus captures a significant shallow-marine oxygenation event closely associated with algal proliferation and the emergence of multicellular life, underscoring the role of biologically mediated environmental feedbacks during the terminal Neoproterozoic. This study enhances our understanding of the interplay between seawater redox structure and microbial activity at the close of the Ediacaran, and supports the interpretation that microbial metabolism may have been a key regulatory mechanism in the devel","PeriodicalId":21575,"journal":{"name":"Sedimentary Geology","volume":"489 ","pages":"Article 106961"},"PeriodicalIF":2.9,"publicationDate":"2025-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145057215","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 : 2025-09-03DOI: 10.1016/j.sedgeo.2025.106959
J. Javier Álvaro , Aram Bayet-Goll , Mehdi Daraei , Blanca Martínez-Benítez
The Alborz Mountains in northern Iran represent one of the few exceptions to the worldwide decline in Miaolingian–Furongian (Cambrian) carbonate abundance and reefal volume, likely related to the arrival of northeastern Gondwana to subtropical latitudes. This Gondwana margin recorded the stepwise nucleation of microbial and shelly carbonate factories, lithostratigraphically recognized as members of the Lalun and Mila formations. The late Cambrian Epoch 2 to Miaolingian interval displays the development of oncoid-pisoid accumulations and microbial build-ups, with laminated and clotted textures, in open-sea and protected (back-barrier) settings. In contrast, the late Miaolingian and Furongian interval recorded a generalized establishment of pelmatozoan-rhynchonelliformean meadows, locally affected by horst-and-graben topographies. Hanging-wall blocks offered some protection from high-energy, shallow-water conditions, which favoured the growth of anthaspidellid-microbial reef complexes. The primary porosity recorded in the pelmatozoan-rhynchonelliformean shell beds, and the associated microboring and micritization of skeletal walls, favoured the episodic development of carbonate and iron oxyhydroxide hardgrounds. Such a singularity leads to the development of a more comprehensive global model linked to Miaolingian–Furongian progressive declines in 87Sr/86Sr ratios, estimated extent of carbonate platforms and reefal volume and atmospheric O2 (punctuated by a sharp increase related to the SPICE event), coeval with relative increases in seawater calcite saturation. In some subtropical areas, such as in the Alborz margin of Gondwana, the re-occurrence of metazoan frame-builders took place in late Miaolingian times, and their subsequent reefal success was primarily controlled by tectonic activity and the nucleation of hardgrounds in highly porous pelmatozoan-rhynchonelliformean shell beds.
{"title":"Cambrian reef complexes and pelmatozoan-rhynchonelliformean meadows from the Alborz Mountains, northern Iran: A reassessment of the Miaolingian–Furongian paucity of metazoan reefs paradigm","authors":"J. Javier Álvaro , Aram Bayet-Goll , Mehdi Daraei , Blanca Martínez-Benítez","doi":"10.1016/j.sedgeo.2025.106959","DOIUrl":"10.1016/j.sedgeo.2025.106959","url":null,"abstract":"<div><div>The Alborz Mountains in northern Iran represent one of the few exceptions to the worldwide decline in Miaolingian–Furongian (Cambrian) carbonate abundance and reefal volume, likely related to the arrival of northeastern Gondwana to subtropical latitudes. This Gondwana margin recorded the stepwise nucleation of microbial and shelly carbonate factories, lithostratigraphically recognized as members of the Lalun and Mila formations. The late Cambrian Epoch 2 to Miaolingian interval displays the development of oncoid-pisoid accumulations and microbial build-ups, with laminated and clotted textures, in open-sea and protected (back-barrier) settings. In contrast, the late Miaolingian and Furongian interval recorded a generalized establishment of pelmatozoan-rhynchonelliformean meadows, locally affected by horst-and-graben topographies. Hanging-wall blocks offered some protection from high-energy, shallow-water conditions, which favoured the growth of anthaspidellid-microbial reef complexes. The primary porosity recorded in the pelmatozoan-rhynchonelliformean shell beds, and the associated microboring and micritization of skeletal walls, favoured the episodic development of carbonate and iron oxyhydroxide hardgrounds. Such a singularity leads to the development of a more comprehensive global model linked to Miaolingian–Furongian progressive declines in <sup>87</sup>Sr/<sup>86</sup>Sr ratios, estimated extent of carbonate platforms and reefal volume and atmospheric O<sub>2</sub> (punctuated by a sharp increase related to the SPICE event), coeval with relative increases in seawater calcite saturation. In some subtropical areas, such as in the Alborz margin of Gondwana, the re-occurrence of metazoan frame-builders took place in late Miaolingian times, and their subsequent reefal success was primarily controlled by tectonic activity and the nucleation of hardgrounds in highly porous pelmatozoan-rhynchonelliformean shell beds.</div></div>","PeriodicalId":21575,"journal":{"name":"Sedimentary Geology","volume":"489 ","pages":"Article 106959"},"PeriodicalIF":2.9,"publicationDate":"2025-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145057214","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 : 2025-09-02DOI: 10.1016/j.sedgeo.2025.106958
Zixiao Peng , Jianhua Qu , En Xie , Chunqiang Chen , Bang Zeng , Dancheng Zhu , Ke Zhang , Yuyuan Li , He Wang
Depositional processes recorded by coastal deposits may vary rapidly during transgression due to the interactions of wave, river, and tidal processes, leading to the diversity of facies models. Reconstructing a reliable, detailed facies model associated with depositional processes remains challenging unless ichnological features are considered. Integrated sedimentological and ichnological analyses of high-resolution core samples, wireline log, and seismic data from the Lower Cretaceous Zubair Formation, central Mesopotamian Basin, are undertaken to propose a tide-dominated model within transgressive succession. The presence of sporadic river-influenced sedimentary structures, variability in ichnodiversity and bioturbation intensity, and abundant tidal physical indicators attest to the strong influence of tide-generated currents during deposition. In a transgressive upward-fining succession, seven facies associations are identified based on differences in sedimentological and ichnological indicators, and further grouped into two environments (tide-dominated estuary and open coast tidal flat), which are both considered as first-order tidal coastal environments. Deposits of estuaries are occupied by mixed Cruziana-Skolithos ichnofacies and dominance of channel-bar complexes, while local storm-influenced structures, higher ichnodiversity and bioturbation intensity, and well-expressed Cruziana and Skolithos ichnofacies clearly characterize the open coast. River-dominated paleovalley evolved into the tide-dominated estuary and then transformed into the open coast tidal flat as global sea-level rose, with increasing ichnodiversity, bioturbation intensity, and weakening fluvial influence. For the first time in the region, distinct deposits of estuary and open coast are recognized, indicating the development of facies diversity during long-term transgression. High accommodation, topographic features, limited sediment supply, and sea level rise are responsible for the spatiotemporal differential distribution of these two depositional systems. At the regional scale, tidal environments, river-influenced, and river-dominated deltas were distributed along the coastline from northwest to southeast due to the relatively increasing sediment supply from the Arabian Shield towards the southeast. The results of this study improve our understanding of regional paleogeography in the central Mesopotamian Basin, NE Arabian Plate, during the Barremian, and provide a case for understanding the diversity and sedimentary evolution of tidal facies models, which can be applied to other transgressive sequences in deep-time basins worldwide.
{"title":"Sedimentological and ichnological characterization of tide-dominated succession during transgression in the Lower Cretaceous Zubair Formation, central Mesopotamian Basin","authors":"Zixiao Peng , Jianhua Qu , En Xie , Chunqiang Chen , Bang Zeng , Dancheng Zhu , Ke Zhang , Yuyuan Li , He Wang","doi":"10.1016/j.sedgeo.2025.106958","DOIUrl":"10.1016/j.sedgeo.2025.106958","url":null,"abstract":"<div><div>Depositional processes recorded by coastal deposits may vary rapidly during transgression due to the interactions of wave, river, and tidal processes, leading to the diversity of facies models. Reconstructing a reliable, detailed facies model associated with depositional processes remains challenging unless ichnological features are considered. Integrated sedimentological and ichnological analyses of high-resolution core samples, wireline log, and seismic data from the Lower Cretaceous Zubair Formation, central Mesopotamian Basin, are undertaken to propose a tide-dominated model within transgressive succession. The presence of sporadic river-influenced sedimentary structures, variability in ichnodiversity and bioturbation intensity, and abundant tidal physical indicators attest to the strong influence of tide-generated currents during deposition. In a transgressive upward-fining succession, seven facies associations are identified based on differences in sedimentological and ichnological indicators, and further grouped into two environments (tide-dominated estuary and open coast tidal flat), which are both considered as first-order tidal coastal environments. Deposits of estuaries are occupied by mixed <em>Cruziana-Skolithos</em> ichnofacies and dominance of channel-bar complexes, while local storm-influenced structures, higher ichnodiversity and bioturbation intensity, and well-expressed <em>Cruziana and Skolithos</em> ichnofacies clearly characterize the open coast. River-dominated paleovalley evolved into the tide-dominated estuary and then transformed into the open coast tidal flat as global sea-level rose, with increasing ichnodiversity, bioturbation intensity, and weakening fluvial influence. For the first time in the region, distinct deposits of estuary and open coast are recognized, indicating the development of facies diversity during long-term transgression. High accommodation, topographic features, limited sediment supply, and sea level rise are responsible for the spatiotemporal differential distribution of these two depositional systems. At the regional scale, tidal environments, river-influenced, and river-dominated deltas were distributed along the coastline from northwest to southeast due to the relatively increasing sediment supply from the Arabian Shield towards the southeast. The results of this study improve our understanding of regional paleogeography in the central Mesopotamian Basin, NE Arabian Plate, during the Barremian, and provide a case for understanding the diversity and sedimentary evolution of tidal facies models, which can be applied to other transgressive sequences in deep-time basins worldwide.</div></div>","PeriodicalId":21575,"journal":{"name":"Sedimentary Geology","volume":"489 ","pages":"Article 106958"},"PeriodicalIF":2.9,"publicationDate":"2025-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145057183","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 : 2025-09-01DOI: 10.1016/j.sedgeo.2025.106957
Ondřej Bábek , Hedvika Weinerová , Lukáš Ackerman , Daniel Šimíček , Jaroslav Kapusta , Ladislav Strnad
The palaeoclimatic significance of continental red beds (CRB) is the subject of a long-standing debate. The CRBs are strikingly often found in association with arid, aeolian sediments, humid fluvial sediments and palaeosols, reflecting variable climatic regimes. In this study, diffuse reflectance spectroscopy (DRS) is used in combination with facies analysis, petrology, bulk-rock and in-situ major and trace element geochemistry, and molybdenum stable isotopes to better understand the origin and distribution of the hematite pigment in a spectrum of Permo-Triassic aeolian, fluvial and pedogenic facies of the Colorado Plateau, Utah. Their red colour is characterized by high (> 30) percentage of red-band (625–700 nm) reflectance in the DRS spectra and high hematite-to-goethite peak height ratios (1.5 to 5.7) from their first derivatives. Most hematite occurs in form of submicronic to micron-sized, platy crystals in altered biotite grains, clayey grain coatings, clayey matrix, pyrite framboid pseudomorphs, and as pore-filling cement. Hematite is most abundant in palaeosols, but also present in aeolian, sand dune and damp interdune deposits, fluvial channel-fill, sandy and gravelly bars, and floodplain deposits. Iron for the hematitization was supplied from reductive release of Fe2+ from biotite and clay minerals. The hematitization itself occurred under oxic conditions, associated with formation of kaolinite, mobilization of V, Mo, As, U, and fractionation of rare earth elements and Mo isotopes, especially in lateritic palaeosols. Hematitization during weathering, pedogenesis, transportation and early diagenesis, and reworking and redeposition of the red material by rivers and wind is thought to be the principal mechanism of the formation of red beds in the Colorado Plateau. The processes of hematitization and the fluvial-aeolian dynamics were controlled by alternation of wetter and drier periods likely caused by the Permo-Triassic Pangean mega-monsoonal climatic regime.
{"title":"Petrological and geochemical evidence of hematite growth and dispersal in Permo-Triassic red beds under the Pangea mega-monsoon climate, Colorado Plateau, Utah","authors":"Ondřej Bábek , Hedvika Weinerová , Lukáš Ackerman , Daniel Šimíček , Jaroslav Kapusta , Ladislav Strnad","doi":"10.1016/j.sedgeo.2025.106957","DOIUrl":"10.1016/j.sedgeo.2025.106957","url":null,"abstract":"<div><div>The palaeoclimatic significance of continental red beds (CRB) is the subject of a long-standing debate. The CRBs are strikingly often found in association with arid, aeolian sediments, humid fluvial sediments and palaeosols, reflecting variable climatic regimes. In this study, diffuse reflectance spectroscopy (DRS) is used in combination with facies analysis, petrology, bulk-rock and in-situ major and trace element geochemistry, and molybdenum stable isotopes to better understand the origin and distribution of the hematite pigment in a spectrum of Permo-Triassic aeolian, fluvial and pedogenic facies of the Colorado Plateau, Utah. Their red colour is characterized by high (> 30) percentage of red-band (625–700 nm) reflectance in the DRS spectra and high hematite-to-goethite peak height ratios (1.5 to 5.7) from their first derivatives. Most hematite occurs in form of submicronic to micron-sized, platy crystals in altered biotite grains, clayey grain coatings, clayey matrix, pyrite framboid pseudomorphs, and as pore-filling cement. Hematite is most abundant in palaeosols, but also present in aeolian, sand dune and damp interdune deposits, fluvial channel-fill, sandy and gravelly bars, and floodplain deposits. Iron for the hematitization was supplied from reductive release of Fe<sup>2+</sup> from biotite and clay minerals. The hematitization itself occurred under oxic conditions, associated with formation of kaolinite, mobilization of V, Mo, As, U, and fractionation of rare earth elements and Mo isotopes, especially in lateritic palaeosols. Hematitization during weathering, pedogenesis, transportation and early diagenesis, and reworking and redeposition of the red material by rivers and wind is thought to be the principal mechanism of the formation of red beds in the Colorado Plateau. The processes of hematitization and the fluvial-aeolian dynamics were controlled by alternation of wetter and drier periods likely caused by the Permo-Triassic Pangean mega-monsoonal climatic regime.</div></div>","PeriodicalId":21575,"journal":{"name":"Sedimentary Geology","volume":"489 ","pages":"Article 106957"},"PeriodicalIF":2.9,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145057213","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 : 2025-08-14DOI: 10.1016/j.sedgeo.2025.106948
Haocheng Shi , Benzhong Xian , Yichen Liu , Zhiyun Yu , Lin Zhao , Junyang Geng , Rongheng Tian , Qianran Wu , Li Liu , Yujie Shuai , Yi Shu
Unlike marine sedimentary basins, lacustrine sedimentary basins are more sensitive to small-scale climatic changes (fourth-order and higher sequences: spanning thousands to tens of thousands of years), and exhibit characteristics such as rapid sedimentary facies transitions and strong heterogeneity. Frequent changes in the sedimentary environment significantly influence the development of sedimentary systems and the formation of sequence structures. These factors present new challenges for understanding the sequence architecture and sedimentary evolution in deep-water zones in lacustrine depression basins. Taking the Middle Jurassic Lianggaoshan Formation in the eastern Sichuan Basin, China, as an example, in this paper, we integrate data from cores, well logs, element geochemistry, and 3D seismic surveys. By applying the transgression–regression cycle theory and high-frequency sequence stratigraphy of lacustrine depression basins, we analyze the genetic mechanisms and distribution patterns of different types of sandstone interlayers within the shale interval and investigate the effect of high-frequency climatic changes on sedimentary processes in lacustrine basins. A high-frequency sequence pattern for lacustrine depression basins is established. The results indicate that within the third-order sequence of the Lianggaoshan Formation, during the shale-deposition interval (maximum water abundance period), the lacustrine depression basins were controlled by the 405 ka (fourth-order sequence) climatic cycle, which still demonstrates basin-scale expansion and contraction. In the shale interval, climate-driven lake transgression-regression cycles within fourth-order sequences promoted frequent interbedding of high sedimentation rate, coarse-grained deposits (e.g., deltaic deposits and hyperpycnal flow deposits) and low sedimentation rate, fine-grained deposits (e.g., suspension settling: shallow-water mudstone and deep-water shale). This reveals a high-frequency sequence stratigraphy pattern that demonstrates the coupling mechanism between the sedimentary processes and climatic forcing in lacustrine depression basins. Within the fourth-order sequences, the early transgressive systems tract and late regressive systems tract are characterized by shallow water and arid conditions, which resulted in the development of organic-poor mudstones, while deltaic sandstones prograde into the center of the basin. In contrast, the late transgressive systems tract and early regressive systems tract are marked by deep water and humid conditions, which led to the formation of organic-rich shales, accompanied by hyperpycnal flow sandstones entering the center of the basin. This resulted in the formation of multiple sets of strongly heterogeneous interbedded organic-poor mudstone and organic-rich shale assemblages. The findings establish a high-frequency sequence pattern for these basins, elucidate their internal depositional and facies evolution processes, an
{"title":"High-frequency sequence patterns in lacustrine basins: Insights from delta-hyperpycnal flow systems in the Middle Jurassic shale interval, Sichuan Basin, China","authors":"Haocheng Shi , Benzhong Xian , Yichen Liu , Zhiyun Yu , Lin Zhao , Junyang Geng , Rongheng Tian , Qianran Wu , Li Liu , Yujie Shuai , Yi Shu","doi":"10.1016/j.sedgeo.2025.106948","DOIUrl":"10.1016/j.sedgeo.2025.106948","url":null,"abstract":"<div><div>Unlike marine sedimentary basins, lacustrine sedimentary basins are more sensitive to small-scale climatic changes (fourth-order and higher sequences: spanning thousands to tens of thousands of years), and exhibit characteristics such as rapid sedimentary facies transitions and strong heterogeneity. Frequent changes in the sedimentary environment significantly influence the development of sedimentary systems and the formation of sequence structures. These factors present new challenges for understanding the sequence architecture and sedimentary evolution in deep-water zones in lacustrine depression basins. Taking the Middle Jurassic Lianggaoshan Formation in the eastern Sichuan Basin, China, as an example, in this paper, we integrate data from cores, well logs, element geochemistry, and 3D seismic surveys. By applying the transgression–regression cycle theory and high-frequency sequence stratigraphy of lacustrine depression basins, we analyze the genetic mechanisms and distribution patterns of different types of sandstone interlayers within the shale interval and investigate the effect of high-frequency climatic changes on sedimentary processes in lacustrine basins. A high-frequency sequence pattern for lacustrine depression basins is established. The results indicate that within the third-order sequence of the Lianggaoshan Formation, during the shale-deposition interval (maximum water abundance period), the lacustrine depression basins were controlled by the 405 ka (fourth-order sequence) climatic cycle, which still demonstrates basin-scale expansion and contraction. In the shale interval, climate-driven lake transgression-regression cycles within fourth-order sequences promoted frequent interbedding of high sedimentation rate, coarse-grained deposits (e.g., deltaic deposits and hyperpycnal flow deposits) and low sedimentation rate, fine-grained deposits (e.g., suspension settling: shallow-water mudstone and deep-water shale). This reveals a high-frequency sequence stratigraphy pattern that demonstrates the coupling mechanism between the sedimentary processes and climatic forcing in lacustrine depression basins. Within the fourth-order sequences, the early transgressive systems tract and late regressive systems tract are characterized by shallow water and arid conditions, which resulted in the development of organic-poor mudstones, while deltaic sandstones prograde into the center of the basin. In contrast, the late transgressive systems tract and early regressive systems tract are marked by deep water and humid conditions, which led to the formation of organic-rich shales, accompanied by hyperpycnal flow sandstones entering the center of the basin. This resulted in the formation of multiple sets of strongly heterogeneous interbedded organic-poor mudstone and organic-rich shale assemblages. The findings establish a high-frequency sequence pattern for these basins, elucidate their internal depositional and facies evolution processes, an","PeriodicalId":21575,"journal":{"name":"Sedimentary Geology","volume":"487 ","pages":"Article 106948"},"PeriodicalIF":2.9,"publicationDate":"2025-08-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144889096","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 stromatolitic tufa with annual growth bands and a large growth rate is a promising archive for high-resolution paleoclimate reconstruction. However, a tufa formed in a fluvial setting typically lacks continuity of deposition. To obtain a continuous record, a potential study material is a cascade-type tufa growing below a waterfall. Here, we study tufas along Kobaru Beach on Tokunoshima Island, Japan, where cascade-type tufas are developed. Oxygen and carbon isotope ratios (δ18O and δ13C) of tufa samples collected from three sites with different sedimentary settings provide information about precipitation patterns and water temperature. A tufa sample from a fluvial setting exhibits clear annual growth rings, rapid growth rates, and seasonal changes in isotopic composition over approximately 20 years. Tufas of the stalagmite-type and cascade-type, having less clear annual growth rings and lower growth rates, preserve continuous records over the last 200 years, the longest record from the modern tufas. The δ13C of the cascade-type tufa shows a decreasing trend from the 1980s, which is interpreted as a result of fossil fuel consumption and an increase in rainfall. In addition, the δ13C of the cascade-type tufa tends to increase in dry intervals and decrease in humid intervals. On the other hand, an approximately 20-year periodicity is observed in the δ18O. Analysis of rainwater samples implies that the δ18O of tufa reflects the seasonality of rainfall, which is inherited from the rainwater δ18O. This interpretation is verified by the consistency between the actual record and the seasonality reconstructed by the tufa δ18O. While cascade-type tufas do not provide sub-annual resolution, they serve as valuable centennial-scale climate archives, which allow us to investigate decadal-scale climate variability, such as Pacific Decadal Oscillation.
{"title":"High-resolution isotopic records for the last 200 years from cascade tufas on Kobaru Beach, Tokunoshima Island, Japan","authors":"Akira Murata , Akihiro Kano , Aki Sakuma , Hirokazu Kato","doi":"10.1016/j.sedgeo.2025.106949","DOIUrl":"10.1016/j.sedgeo.2025.106949","url":null,"abstract":"<div><div>A stromatolitic tufa with annual growth bands and a large growth rate is a promising archive for high-resolution paleoclimate reconstruction. However, a tufa formed in a fluvial setting typically lacks continuity of deposition. To obtain a continuous record, a potential study material is a cascade-type tufa growing below a waterfall. Here, we study tufas along Kobaru Beach on Tokunoshima Island, Japan, where cascade-type tufas are developed. Oxygen and carbon isotope ratios (δ<sup>18</sup>O and δ<sup>13</sup>C) of tufa samples collected from three sites with different sedimentary settings provide information about precipitation patterns and water temperature. A tufa sample from a fluvial setting exhibits clear annual growth rings, rapid growth rates, and seasonal changes in isotopic composition over approximately 20 years. Tufas of the stalagmite-type and cascade-type, having less clear annual growth rings and lower growth rates, preserve continuous records over the last 200 years, the longest record from the modern tufas. The δ<sup>13</sup>C of the cascade-type tufa shows a decreasing trend from the 1980s, which is interpreted as a result of fossil fuel consumption and an increase in rainfall. In addition, the δ<sup>13</sup>C of the cascade-type tufa tends to increase in dry intervals and decrease in humid intervals. On the other hand, an approximately 20-year periodicity is observed in the δ<sup>18</sup>O. Analysis of rainwater samples implies that the δ<sup>18</sup>O of tufa reflects the seasonality of rainfall, which is inherited from the rainwater δ<sup>18</sup>O. This interpretation is verified by the consistency between the actual record and the seasonality reconstructed by the tufa δ<sup>18</sup>O. While cascade-type tufas do not provide sub-annual resolution, they serve as valuable centennial-scale climate archives, which allow us to investigate decadal-scale climate variability, such as Pacific Decadal Oscillation.</div></div>","PeriodicalId":21575,"journal":{"name":"Sedimentary Geology","volume":"487 ","pages":"Article 106949"},"PeriodicalIF":2.9,"publicationDate":"2025-08-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144879912","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 : 2025-08-13DOI: 10.1016/j.sedgeo.2025.106947
Gustavo Kenji Lacerda-Orita , Fernando Pérez-Valera , Jesús M. Soria , Hugo Corbí , Jingjing Liu , Núria Sierra-Ramirez , Enrique Gomez-Rivas , Luis Gibert
The Tabernas Basin (SE-Spain), renowned for its Tortonian turbidites, also records thick Messinian successions (>200 m) that offer valuable insights into the Messinian Salinity Crisis (MSC). Yet, the stratigraphic correlation of the Tabernas sediments with the classic successions of the nearby Sorbas Basin remains unclear. This study presents a composite stratigraphic section (named Yesón Alto) that covers the pre-evaporitic, syn-evaporitic, and supra-evaporitic stages of the MSC recorded in Tabernas Basin, offering detailed paleoenvironmental and chronostratigraphic characterization. We provide new constraints on the connections between two marginal basins of the Betic Cordillera and on the paleoenvironmental changes that took place in the Western Mediterranean during the MSC. During the Late Messinian pre-evaporitic phase, siltstones and shales alternating with distal turbidites recorded shifts between warm-oligotrophic and cold-eutrophic planktonic foraminiferal assemblages, indicating the influence of precession-driven climatic fluctuations on the water column. Progressive basin restriction led to the development of an incipient hybrid carbonate shelf, subjected to significant siliciclastic influx. 16 key planktonic foraminifera bioevents and a magnetic reversal (C3An.1n to C3r at 6.035 Ma) have been identified and correlated with the astronomically calibrated cycles of the Sorbas Basin, suggesting the possible synchronous onset of the MSC in both basins. The evaporitic stage in Tabernas is represented by four selenitic gypsum beds intercalated with siliciclastic and carbonate deposits. Facies analysis and gypsum isotopic compositions (δ34Ssulfate and δ18Osulfate) suggest that evaporites represent the initial cycles of the Primary Lower Gypsum (PLG) of the MSC Stage 1 in the Mediterranean. Below gypsum bed PLG 4, an inter-evaporitic level rich in marine fauna indicates the episodic re-establishment of near-normal marine conditions after periods of evaporite precipitation. The Supra-evaporitic unit, comprising deltaic-fluvial conglomerates and sandstones, reflects a regional regressive trend and marks the continentalization of the basin's margins. The progradation of these continental deposits over the evaporitic basin was favored by an eastward uplift trend in the Betic Cordillera, ultimately leading to exposure of the Tabernas Basin before or during Stages 2 and 3 of the MSC. The paleoenvironmental evolution of the Tabernas Basin indicates that marine connections with the Sorbas Basin persisted before and during the early MSC and that tectonics associated with climatic factors played a key role in the evolution of its sedimentary systems.
{"title":"A new sedimentary record from the Tabernas Basin: Implications for the Messinian Salinity Crisis in the Western Mediterranean","authors":"Gustavo Kenji Lacerda-Orita , Fernando Pérez-Valera , Jesús M. Soria , Hugo Corbí , Jingjing Liu , Núria Sierra-Ramirez , Enrique Gomez-Rivas , Luis Gibert","doi":"10.1016/j.sedgeo.2025.106947","DOIUrl":"10.1016/j.sedgeo.2025.106947","url":null,"abstract":"<div><div>The Tabernas Basin (SE-Spain), renowned for its Tortonian turbidites, also records thick Messinian successions (>200 m) that offer valuable insights into the Messinian Salinity Crisis (MSC). Yet, the stratigraphic correlation of the Tabernas sediments with the classic successions of the nearby Sorbas Basin remains unclear. This study presents a composite stratigraphic section (named Yesón Alto) that covers the pre-evaporitic, syn-evaporitic, and supra-evaporitic stages of the MSC recorded in Tabernas Basin, offering detailed paleoenvironmental and chronostratigraphic characterization. We provide new constraints on the connections between two marginal basins of the Betic Cordillera and on the paleoenvironmental changes that took place in the Western Mediterranean during the MSC. During the Late Messinian pre-evaporitic phase, siltstones and shales alternating with distal turbidites recorded shifts between warm-oligotrophic and cold-eutrophic planktonic foraminiferal assemblages, indicating the influence of precession-driven climatic fluctuations on the water column. Progressive basin restriction led to the development of an incipient hybrid carbonate shelf, subjected to significant siliciclastic influx. 16 key planktonic foraminifera bioevents and a magnetic reversal (C3An.1n to C3r at 6.035 Ma) have been identified and correlated with the astronomically calibrated cycles of the Sorbas Basin, suggesting the possible synchronous onset of the MSC in both basins. The evaporitic stage in Tabernas is represented by four selenitic gypsum beds intercalated with siliciclastic and carbonate deposits. Facies analysis and gypsum isotopic compositions (δ<sup>34</sup>S<sub>sulfate</sub> and δ<sup>18</sup>O<sub>sulfate</sub>) suggest that evaporites represent the initial cycles of the Primary Lower Gypsum (PLG) of the MSC Stage 1 in the Mediterranean. Below gypsum bed PLG 4, an inter-evaporitic level rich in marine fauna indicates the episodic re-establishment of near-normal marine conditions after periods of evaporite precipitation. The Supra-evaporitic unit, comprising deltaic-fluvial conglomerates and sandstones, reflects a regional regressive trend and marks the continentalization of the basin's margins. The progradation of these continental deposits over the evaporitic basin was favored by an eastward uplift trend in the Betic Cordillera, ultimately leading to exposure of the Tabernas Basin before or during Stages 2 and 3 of the MSC. The paleoenvironmental evolution of the Tabernas Basin indicates that marine connections with the Sorbas Basin persisted before and during the early MSC and that tectonics associated with climatic factors played a key role in the evolution of its sedimentary systems.</div></div>","PeriodicalId":21575,"journal":{"name":"Sedimentary Geology","volume":"487 ","pages":"Article 106947"},"PeriodicalIF":2.9,"publicationDate":"2025-08-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144865276","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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