Sedimentary Geology最新文献

{"title":"Corrigendum to “Shell beaches to beachrock: Diagenetic stable isotopic trends” [Sediment. Geol. 391 (2019) 105520]","authors":"Megan Brock Casillas, Henry S. Chafetz","doi":"10.1016/j.sedgeo.2025.106872","DOIUrl":"10.1016/j.sedgeo.2025.106872","url":null,"abstract":"","PeriodicalId":21575,"journal":{"name":"Sedimentary Geology","volume":"481 ","pages":"Article 106872"},"PeriodicalIF":2.7,"publicationDate":"2025-03-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143654777","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Sequence stratigraphy in continental endorheic basins: New contributions from the case of the northern extensional Teruel Basin","authors":"Lope Ezquerro ,&nbsp;Carlos L. Liesa ,&nbsp;José L. Simón ,&nbsp;Aránzazu Luzón","doi":"10.1016/j.sedgeo.2025.106868","DOIUrl":"10.1016/j.sedgeo.2025.106868","url":null,"abstract":"<div><div>The tectono-sedimentary analysis is a sequence stratigraphy method particularly useful in continental tectonically active basins far from the influence of sea level changes. It provides a comprehensive study of the sedimentary features and stratigraphic architecture of a basin focusing on the stratigraphical, mainly cyclic, trend of the rock record in order to define genetic (tectono-sedimentary units-TSUs) controlled by allocyclic factors: tectonics and climate. The tectono-sedimentary analysis has been traditionally used in basins related to compressive stress regimes, but their application in extensional basins is less common. In this work the results of the detailed tectono-sedimentary analysis of the northern Teruel Basin rocks are presented. Vertical and lateral distribution of mappable lithofacies associations reveal different depositional systems laterally related and the main paleogeographic changes from the Late Miocene to Early Gelasian (11–1.8 Myr). Five main alluvial progradational-retrogradational cycles integrate six TSUs with chronostratigraphical meaning, bounded by isochronous stratigraphic surfaces (sedimentary breaks) that represent maximum alluvial progradations, and define the basin geodynamic framework. A main challenge, not commonly addressed in this kind of studies, is the discrimination of the effects of tectonic and climate for each unit, which has been based on evidences of synsedimentary tectonism in combination with δ¹⁸O_PDB isotope data. It is demonstrated that the sedimentary evolution was mainly controlled by the tectonics, with the phases of tectonic activity being consistently recorded as alluvial progradations (correlative lacustrine retractions) and climate only modulating (amplifying or vanishing) the tectonic effects. Certain guidelines are proposed to adequately recognize and characterize genetic units in continental extensional basins. Our results reinforce TSUs as very valuable tools for studying active continental basins far from sea level effects and to discriminate the influence of allogenic controls in sedimentation.</div></div>","PeriodicalId":21575,"journal":{"name":"Sedimentary Geology","volume":"481 ","pages":"Article 106868"},"PeriodicalIF":2.7,"publicationDate":"2025-03-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143679208","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}

{"title":"Upwelling controls organic matter enrichment and organic carbon cycle in the shelf area of the Doushantuo Formation","authors":"Junfeng Zhang ,&nbsp;Detian Yan ,&nbsp;Dan Zhao ,&nbsp;Zeyu Lu","doi":"10.1016/j.sedgeo.2025.106873","DOIUrl":"10.1016/j.sedgeo.2025.106873","url":null,"abstract":"<div><div>As the oldest shale in South China with potential for exploration, the black shale of the second member of the Doushantuo Formation holds significant research importance and economic value because it records the organic carbon cycle during that period. Previous studies have suggested that the formation of the organic-rich black shale in the second member of the Doushantuo Formation was primarily controlled by an anoxic depositional environment. However, investigations of samples from shelf lagoons have revealed otherwise. In this research, microstructural observations, organic carbon content, elemental geochemistry and C_org-N isotopes of the black shale at the Qinglinkou section and well YD in the middle Yangtze were conducted. The results indicate that the formation mechanisms and paleoenvironment of organic-rich shale in the lower and upper halves of the second member are distinct. The presence of apatite and the characteristics of upwelling proxies suggest the occurrence of upwelling during the sedimentation period of the upper half of the second member. The research results indicate that upwelling directly enhances primary productivity levels during sedimentation in the upper half, bolstering the exchange of nutrients and elements within the water column, which facilitates organic matter enrichment and exacerbates the anoxia of deeper waters. In contrast, the organic matter enrichment in the lower half of the Doushantuo Formation's second member is conventional and is governed primarily by anoxic depositional environments; however, it lacks high productivity and is worse overall than the upper half. Moreover, because the water column is restricted, the organic carbon cycle in the lower half is slow and limited. The organic carbon cycle in the upper half benefits from the nutrients brought by upwelling, which results in better formation and preservation. The role of upwelling in altering the deep-water environment of shelf lagoons and in organic matter accumulation and the organic carbon cycle was emphasized in this study, providing guidance for the study of shale deposition globally during the same period.</div></div>","PeriodicalId":21575,"journal":{"name":"Sedimentary Geology","volume":"481 ","pages":"Article 106873"},"PeriodicalIF":2.7,"publicationDate":"2025-03-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143636551","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}

{"title":"Clay mineral of different lithofacies in a continental shallow water delta: Insights from paleoclimate and diagenesis","authors":"Shaoyun Chen ,&nbsp;Yongqiang Yang ,&nbsp;Zaixing Jiang ,&nbsp;Xiaojuan Wang ,&nbsp;Longwei Qiu ,&nbsp;Yerejiepu Habulashenmu","doi":"10.1016/j.sedgeo.2025.106869","DOIUrl":"10.1016/j.sedgeo.2025.106869","url":null,"abstract":"<div><div>Clay minerals in clastic sediments carry important geological information, with their composition and variations reflecting key geological processes. This study investigates the differential clay mineral assemblages among lithofacies within the Middle Jurassic continental shallow-water delta system of the Sichuan Basin, China. Integrated geochemical and XRD analyses demonstrate the significant influence of paleoclimate-driven weathering and diagenetic alteration on clay mineral assemblages. The invariant geochemical characteristics (such as Ti/Al) across different mudstone confirm a uniform provenance, establishing paleoclimate-controlled weathering processes as the principal determinant of clay mineral composition, with negligible provenance influence. Chemical weathering intensity, controlled by the depositional paleoclimate, is a primary factor influencing clay mineral composition in mudstones. In warm, humid climates, abundant rainfall and strong chemical weathering lead to kaolinite enrichment and smectite depletion in black shale facies. Conversely, in cooler, drier climates, physical weathering dominates, resulting in significant illite formation in red mudstone and paleosol facies. In sandstone facies, clay minerals are controlled by diagenetic fluid composition and flux. Chlorite content is related to the primary permeability of the sandstone, while illite content is influenced by K⁺ concentration in diagenetic fluids, with stronger illite enrichment in areas of intense feldspar dissolution. The smectite-to-illite transformation is common in both sandstone and mudstone facies, with its extent influenced by the openness of the diagenetic system and K⁺ availability. In humid conditions, feldspar dissolution in an open system leads to K⁺ advection into sandstone, reducing smectite-to-illite transformation in mudstones. In semi-arid conditions, feldspar dissolution occurs in closed systems during burial, with K⁺ diffusing into mudstones, promoting greater illitization in mudstones than in sandstones. This study provides insights into how paleoclimate and diagenesis control clay mineral transformations in sedimentary rocks.</div></div>","PeriodicalId":21575,"journal":{"name":"Sedimentary Geology","volume":"481 ","pages":"Article 106869"},"PeriodicalIF":2.7,"publicationDate":"2025-03-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143620406","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}

{"title":"Thermal maturity and colors of Cretaceous East Asian fossil eggs","authors":"Seung Choi ,&nbsp;Shukang Zhang ,&nbsp;Noe-Heon Kim ,&nbsp;Jin Jung Kweon ,&nbsp;Kohei Tanaka ,&nbsp;Katsuhiro Kubota ,&nbsp;Yuong-Nam Lee ,&nbsp;Junfang Xie ,&nbsp;In Sung Paik ,&nbsp;Sung Keun Lee","doi":"10.1016/j.sedgeo.2025.106855","DOIUrl":"10.1016/j.sedgeo.2025.106855","url":null,"abstract":"<div><div>Several factors influence the quality of fossil preservation, with temperature being one of the key variables. The maximum temperature that fossils have experienced during their taphonomic history affects their thermal maturity and color. Cretaceous fossil eggs of amniote vertebrates from East Asia were analyzed using Raman spectroscopy to investigate their thermal maturity. Eggs from inland regions of East Asia (Mongolia and inland China) do not show a significant thermal imprint, while eggs from the southern and eastern regions of East Asia (coastal China, Korea, and Japan) show a high thermal maturity. Although this pattern must have been caused by the combined effect of complex factors (e.g., burial depth, stratigraphic position, and local geothermal phenomenon), the rollback of the Paleo-Pacific Plate during the Cretaceous and consequent vigorous igneous activity and/or high heat flow near the subduction boundary may have been one of the main working factors. The approach of this study can be extended to fossil eggs from other continents to elucidate the relationship between thermal maturity and geological setting, and will provide a deeper understanding of fossil egg taphonomy.</div></div>","PeriodicalId":21575,"journal":{"name":"Sedimentary Geology","volume":"481 ","pages":"Article 106855"},"PeriodicalIF":2.7,"publicationDate":"2025-03-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143725983","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}

{"title":"Arc-continent collision as recorded in modern stream sand from Oecusse (Timor Island)","authors":"Victor A.S. Vicente ,&nbsp;Pedro Dinis ,&nbsp;Eduardo Garzanti ,&nbsp;Alberto Resentini ,&nbsp;Marta Barbarano ,&nbsp;Marina Cabral Pinto ,&nbsp;João Pratas","doi":"10.1016/j.sedgeo.2025.106852","DOIUrl":"10.1016/j.sedgeo.2025.106852","url":null,"abstract":"<div><div>The small territory of Oecusse in Timor Island has extremely complex geology, influenced by the collision of the Australian continent with the Banda Arc. In Oecusse, sedimentary, volcanic and metamorphic units associated with the lower plate Australian continental margin, the upper plate Banda Terrane, and synorogenic sedimentary successions are exposed. In this study, geochemistry, petrography, and heavy-mineral data on fluvial bedload sand transported by first- and second-order streams are used to better understand the status of arc-continent collision in Timor and the geological nature of the terranes involved in this tectonic process. The presence of upper mantle outliers in Oecusse is readily revealed by serpentinite grains, a heavy mineral assemblage with enstatite, olivine and Cr-spinel, and by Cr, Fe, Sc, Ti, and V concentrations comparable to the Primitive Mantle standard. Volcanic sources occur both in the Banda Terrane and Australian continental margin. The Manamas Formation (Miocene, Banda Terrane) is the most prominent volcanic source, shedding detritus dominated by mafic volcanic rock fragments, plagioclase, and clinopyroxene, with a geochemical signature similar to the Primitive Mantle. The volcanic units of the Barique Formation (Eocene-Miocene, Banda Terrane) and the Maubisse Formation (Permian, Australian continental margin) comprise compositionally heterogenous suites and are intercalated with sedimentary successions, delivering more felsic material, as indicated by the diversified assemblages of lithic fragments and heavy-minerals. Geochemically, they are characterised by lower contents of most compatible elements, higher contents of Th, Y and REE, steeper REE profiles, and stronger negative Eu anomaly than Manamas-derived detritus. These petrographic and geochemical features locally reveal a major felsic volcanic component in the Barique Formation, which cannot be related to the ongoing orogeny because of its proposed late Eocene to early Miocene age. With the exception of coastal sectors where the Manamas Formation is widely exposed, volcanic, sedimentary and low-rank meta-sedimentary rocks partially derived from the Australian lower plate tend to prevail, confirming that arc-continent collision is still at an early stage in the western part of Timor Island.</div></div>","PeriodicalId":21575,"journal":{"name":"Sedimentary Geology","volume":"481 ","pages":"Article 106852"},"PeriodicalIF":2.7,"publicationDate":"2025-03-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143654776","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Origin and deposition of deepwater homogenites from a sedimentological perspective: Examples from offshore SW Taiwan","authors":"Radha Krishna Pillutla ,&nbsp;Andrew Tien-Shun Lin ,&nbsp;Jen-Chu Yeh ,&nbsp;Gueorgui Ratzov ,&nbsp;Nathalie Babonneau ,&nbsp;Shu-Kun Hsu ,&nbsp;Chih-Chieh Su ,&nbsp;Serge Lallemand ,&nbsp;Ludvig Löwemark","doi":"10.1016/j.sedgeo.2025.106854","DOIUrl":"10.1016/j.sedgeo.2025.106854","url":null,"abstract":"<div><div>A giant piston core, MD18–3548 (20.07 m) was collected from a perched basin in the Taiwan accretionary wedge, at a water depth of 1752 m. Detailed grain-size analysis, ¹⁴C accelerator mass spectrometry (AMS) dating, and computed tomography (X-CT) scans of the core were performed. Four types of lithofacies, namely hemipelagic sediments, silty turbidite-homogenites, turbidites, and thin silty layers, are identified, along with seventeen event beds. A total of fourteen ¹⁴C AMS dating were carried out, with the depositional ages of the event beds being calculated based on the sedimentation rate of hemipelagites. The oldest event bed is ∼12 cal kyrs BP, while the youngest event bed is ∼64 cal yrs BP. All seven homogenite units are floored by a thin (usually &lt;10 cm thick), coarsening-upward first and then fining-upward unit, capped by a thick structureless mud totally devoid of bioturbation. The average thickness of homogenite units is ∼150 cm, while the thickest homogenite unit is ∼200 cm. These homogenite units can be compared to similar deposits reported elsewhere and find particularly that these units exhibit a basal layer with gradual coarsening and fining upward trend in grain size. We therefore propose a new depositional model for the silty turbidite-homogenite units in seismically-shaken enclosed basins. This model takes into account the coarsening-then-fining upward deposition of the basal layers, reported for the first time.</div></div>","PeriodicalId":21575,"journal":{"name":"Sedimentary Geology","volume":"480 ","pages":"Article 106854"},"PeriodicalIF":2.7,"publicationDate":"2025-03-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143551819","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Trace element and OH content of quartz grains in the Amazon river: Potential application in provenance analysis","authors":"R. Stalder ,&nbsp;D. Jaeger ,&nbsp;S. Andò ,&nbsp;E. Garzanti ,&nbsp;C.M. Chiessi ,&nbsp;A.O. Sawakuchi ,&nbsp;T. Ludwig ,&nbsp;M. Strasser","doi":"10.1016/j.sedgeo.2025.106853","DOIUrl":"10.1016/j.sedgeo.2025.106853","url":null,"abstract":"<div><div>Quartz grains in sediment carried by the Amazon River and five of its major tributaries were analyzed by FTIR-spectroscopy and secondary ion mass spectrometry to evaluate their potential for provenance analysis. Additionally, heavy mineral analysis was performed in the same samples to support sediment discrimination and provenance interpretation. Average defect water contents in quartz grains carried by branches with headwaters draining the Andes are higher (Solimões River 8.8 wt ppm, Madeira River 7.2 wt ppm) than in branches exclusively draining cratonic areas (Xingu River 6.5 wt ppm, Tapajós River 4.6 wt ppm, Negro River 4.7 wt ppm); values in one Amazon mainstem sample are intermediate with prevalence of the Andean signal (7.7 wt ppm). The average defect water content correlates to the fraction of grains that are defect-water rich (&gt; 10 wt ppm), ranging from 30 to 40 % for the Solimões, Madeira, and Amazon Rivers down to 10–20 % for the Tapajós and Negro Rivers. The average molecular-water signal exhibits a much clearer contrast than the OH-defect signal. Grains from cratonic tributaries (Negro, Tapajós and Xingu rivers) exhibit significantly weaker molecular water signals than grains from Andean tributaries (Solimões and Madeira rivers); slightly weaker than the latter is the signal from grains in the Amazon mainstem, reflecting a mixture of Solimões and Negro rivers quartz in the Amazon mainstem sample.</div><div>In contrast, trace-element concentrations widely overlap among samples, preventing any robust discrimination about the sources of quartz grains. Trace metals show a fair correlation between Li and Al in all samples; a weak correlation between Al and Ti (indicative of igneous origin) was observed in Negro, Xingu and Amazon River sands, but not in Solimões, Madeira and Tapajós sands. Boron correlates with Li in Tapajós river and Amazon mainstem samples and with Al in Madeira and Tapajós samples.</div><div>Heavy-minerals are mostly amphibole, epidote, augitic clinopyroxene and hypersthene in Solimões River sands largely derived from the Andes, and andalusite, amphibole and epidote in Madeira River sands. Cratonic tributaries contribute durable tourmaline and zircon with andalusite (Negro River) or staurolite and topaz (Tapajós River).</div><div>The higher content of OH defects and molecular water in quartz grains derived from the Andes than in those from cratonic areas indicates that this property can provide useful complementary information to discriminate the source of quartz grains, one of the thorniest tasks in provenance analysis.</div></div>","PeriodicalId":21575,"journal":{"name":"Sedimentary Geology","volume":"480 ","pages":"Article 106853"},"PeriodicalIF":2.7,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143551818","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Geochemical composition and grain size of surface sediments from reticulate dunes in the Tengger Desert, China","authors":"Junguang Wang ,&nbsp;Zhibao Dong ,&nbsp;Zhengcai Zhang ,&nbsp;Rongliang Liu ,&nbsp;Jiqiao Shi ,&nbsp;Ping Lü","doi":"10.1016/j.sedgeo.2025.106851","DOIUrl":"10.1016/j.sedgeo.2025.106851","url":null,"abstract":"<div><div>Reticulate dunes are the prevalent type of dunes found in deserts worldwide. However, compared to other dune types, systematic research on reticulate dunes remains limited, and aspects such as their formation mechanisms, grain size characteristics, and elemental composition characteristics remain inadequately understood. This study integrated regional wind regime data to analyse the grain size characteristics of reticulate dunes (specifically, the primary and secondary ridges) in the Tengger Desert, Considering both primary and sub-wind seasons. Additionally, we examined the elemental composition characteristics and degree of weathering of these dunes. The results indicate that the primary and secondary ridges of the reticulate dunes in the Tengger Desert are predominantly composed of fine sand and very fine sand with a mean grain size of 2.52Φ. Compared with other deserts in China and abroad, the sediments exhibit relatively finer grain sizes and better sorting. Furthermore, the grain size characteristics of surface sediments in the primary and secondary ridges exhibited two distinct distribution patterns during different wind seasons, indicating differences in the formation mechanisms of the primary and secondary ridges. The major elements in the surface sediments of the reticulate dunes in the Tengger Desert are SiO₂ and Al₂O₃, while the predominant trace elements are primarily Ba, Sr, Zr, and Cr. This indicates that the geochemical composition of the sediments is influenced not only by the intrinsic characteristics of the elements but also by the regional climate and the supply of fresh materials, which are significant factors affecting their chemical behavior and content differences. The chemical weathering indices (CIA, residual coefficient, and ICV), along with the A-CN-K and A-CNK-FM triangular diagrams, suggest that the sedimentary environment of the reticulate dune sediments in the Tengger Desert is characterised by a cold, dry climate with a low degree of weathering. The weathering process occurs during the initial stages of plagioclase chemical weathering. These findings lay the foundation for further research on the formation mechanisms, evolutionary processes, and sedimentary environments of reticulate dunes, contributing to a deeper understanding of these complex geomorphological features.</div></div>","PeriodicalId":21575,"journal":{"name":"Sedimentary Geology","volume":"480 ","pages":"Article 106851"},"PeriodicalIF":2.7,"publicationDate":"2025-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143551817","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The importance of sedimentary structures in fine-grained deposits in re-interpreting the Facies mosaic of Lower Triassic tide-influenced deltas","authors":"Ibrahim Zallum","doi":"10.1016/j.sedgeo.2025.106850","DOIUrl":"10.1016/j.sedgeo.2025.106850","url":null,"abstract":"<div><div>Despite considerable progress in their description and characterization, tide-dominated deltas remain the least understood of the three main delta classes. Fine-grained sediments of the deltaic subenvironments remain particularly understudied, especially via ultra-thin section analysis. Such analysis can aid in identifying subenvironments typically missed in paleodelta analysis (e.g., delta plains). Combined with other methods, they can prove valuable in evaluating depositional and sequence-stratigraphic models and exploring the interplay between sediment supply and channel morphologies.</div><div>This study focuses on the Lower Triassic Torrey Member of the Moenkopi Formation of southern Utah. Previous interpretations posit that the Torrey Member represents a tide-dominated delta deposited in three depositional sequences. Integrating mudstone thin section analysis helped reveal that the Torrey Member contains ten facies associations, with the facies architecture indicating deposition by tide-dominated or tide-influenced deltas over a single depositional sequence. The progradational phase is notable for its decreased channel density and concurrent increase in subaerial exposure indicators. This study posits that hyperycnal flows, including bedload transport, dominated deposition in the prodelta and delta front of the Torrey Member, with no direct evidence of tidal processes.</div><div>This study broadly demonstrates the importance of integrating mudstone thin-section analysis in paleodelta studies. This paper particularly draws particular attention to delta plain identification in semi-arid and arid settings and suggests that thin-section analysis may reveal examples previously missed in similar paleodeltas.</div></div>","PeriodicalId":21575,"journal":{"name":"Sedimentary Geology","volume":"480 ","pages":"Article 106850"},"PeriodicalIF":2.7,"publicationDate":"2025-02-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143562081","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}