{"title":"Hydrologically sensitive carbonates: Tectonic and groundwater controls on synrift sedimentation in the Late Jurassic–Early Cretaceous of the western Cameros Basin, Northern Spain","authors":"Nigel H. Platt, V. Paul Wright","doi":"10.1002/dep2.317","DOIUrl":"https://doi.org/10.1002/dep2.317","url":null,"abstract":"<p>Basin hydrology and subcrop are key controls on carbonate sedimentation in continental basins. Hydrologically sensitive carbonates can record groundwater fluctuations within an aquifer in deep time. Late Jurassic extension, footwall uplift, erosion and karstification of marine Jurassic carbonates in the western Cameros Basin (Spain) saw deposition of ?Upper Kimmeridgian-Tithonian syntectonic alluvial fan deposits (Señora de Brezales Formation). Biogenic laminar calcretes and phreatophytic rhizocretions record roots exploiting capillary fringe groundwater. Progressive infill of rift topography and footwall erosion lowered sedimentary gradients and clastic supply during deposition of the ?Tithonian–Berriasian Rupelo Formation. Distal alluvial marls (Las Viñas Member) contain charophytes, with 2 m thick carbonate lenses at the top reflecting intermittent rise of groundwater in ponds on the basin floor. Stacked palustrine limestones with rare charophytes and laminar calcretes (Ladera Member) record overstep of seasonal carbonate wetlands onto basin margins and footwall highs with intense pedogenetic modification during lengthy seasonal exposure. Overlying Berriasian charophyte-ostracod wackestones, displaying microkarst cavities and interbedded intraclastic conglomerates, with vivianite sauropod bones, footprints and polygonal desiccation cracks at the top (Mambrillas de Lara Member) record open lacustrine conditions with limited subaerial exposure and high water tables. Desiccation-cracked limestones and marls with correlatable evaporite horizons (Rio Cabrera Member) contain marginal marine foraminifera and dasycladaceae at the top. Lagoonal conditions reflected transgression to seaward and intermittent marine connection via the Basco-Cantabrian Basin. The distribution and thicknesses of hydrologically sensitive carbonates reflected onlap onto a faulted and karstified marine Jurassic carbonate pediment and the subtle influence on hydroperiod of fault (and potentially localised Triassic salt) controlled differential subsidence and transgressive groundwater rise. Hydrological facies evolution reflects progressive basin infilling and eustasy beyond. Transitions in this continental succession from clastic to carbonate facies and from closed to open hydrology record hydrological change over time rather than contemporaneous deposition under Walther's Law.</p>","PeriodicalId":54144,"journal":{"name":"Depositional Record","volume":"11 2","pages":"537-564"},"PeriodicalIF":1.9,"publicationDate":"2024-11-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/dep2.317","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143846095","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A. A. Valencia, J. E. A. Storms, H. R. A. Jagers, H. van der Vegt
{"title":"The influence of syn-depositional compaction on clastic sediment distribution in river-dominated deltas: A modelling study","authors":"A. A. Valencia, J. E. A. Storms, H. R. A. Jagers, H. van der Vegt","doi":"10.1002/dep2.318","DOIUrl":"https://doi.org/10.1002/dep2.318","url":null,"abstract":"<p>Syn-sedimentary compaction or consolidation is an important process in deltaic environments because it affects both the local morphodynamics and hydrodynamics as well as the delta-scale accommodation space. However, the impact of syn-depositional compaction on the sediment distribution and the interdependency between different delta areas related to the sediment budget are not fully understood. This paper simulates syn-depositional compaction using improved 1D grain-size compaction formulations, integrated into hydrodynamic and morphodynamic modelling software Delft3D. The updated code is used to model sedimentation in mud-rich deltas under various compaction rate scenarios, which represents the maximum compaction rate potential of sediment that experiences the highest overburden stress in the delta. The simulated deltas are analysed by first classifying their plan-view area development into depositional elements: distributary channel, underfilled channel, delta plain, mouth bar, delta front and pro delta depositional elements. Then, sedimentation by mass, accommodation space and depositional segment metrics are calculated using the interpreted depositional elements. The results for zero compaction rate scenarios (0 mm year<sup>−1</sup>) show that limited space-varying and temporal-varying accommodation is available to deposit sediment in the delta plain depositional element. Therefore, the sedimentation mainly occurs in the mouth bar depositional element. For low-mid compaction rate scenarios (0.01–1 mm year<sup>−1</sup>), the additional syn-depositional accommodation space in the delta plain depositional element increases sedimentation in this area, limiting sedimentation in the mouth bar depositional element. For high compaction rate scenarios (>1 mm year<sup>−1</sup>), a further increase in the accommodation space in the delta plain depositional element leads to lateral sedimentation attributed to channel relocation, where the sedimentation mainly occurs in the mouth bar depositional element. This study shows that, although considered a gradual process, syn-sedimentary compaction does impact long-term delta evolution by influencing the distribution of sedimentation in the delta.</p>","PeriodicalId":54144,"journal":{"name":"Depositional Record","volume":"11 2","pages":"565-582"},"PeriodicalIF":1.9,"publicationDate":"2024-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/dep2.318","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143846027","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Davide Carraro, Sean P. Gaynor, Dario Ventra, Alexey Ulyanov, Andrea Moscariello
{"title":"Testing the fidelity of zircon as a provenance indicator in fluvial-fan successions: An example from the Palaeogene Colton Formation, Central Utah, USA","authors":"Davide Carraro, Sean P. Gaynor, Dario Ventra, Alexey Ulyanov, Andrea Moscariello","doi":"10.1002/dep2.316","DOIUrl":"https://doi.org/10.1002/dep2.316","url":null,"abstract":"<p>The stratigraphic, spatial and temporal variability of detrital zircon age populations in continental sedimentary successions is a critical tool in understanding palaeodrainage networks and how these systems distributed detritus within sedimentary basins. However, multiple factors, such as variations in sediment-transport processes, the scale of the depositional environment and the architecture of the sedimentary succession are often overlooked in detrital zircon studies. This article presents detrital zircon U–Pb geochronology from the fluvial-dominated Colton Formation in the western Uinta Basin (Utah, USA) to assess the system's provenance and evolution. Significant differences in zircon age populations between the Colton Formation and the overlying Green River Formation suggest a reorganisation of the source-to-sink system during the transition between the two lithostratigraphic units. Notably, detrital zircon age spectra are not homogeneous across the Colton Formation, therefore physical morphometric parameters were used to verify the possible influence of selective bias during sediment transport. These data reveal that a relatively finer-grained population of Precambrian, and to a less extent Mesozoic, zircon grains were affected by hydraulic sorting during transport, resulting in a greater relative abundance of older zircon grains in the distal reaches of the distributive fluvial system, whose basinward decrease in competence would have increased the relative proportion of finer zircon fractions in sandstones. Furthermore, there are different trends in the distributions of zircon age populations relative to their stratigraphic position, highlighting the complex architecture of the fluvial palaeo-fan. The spatial and stratigraphic variability of provenance signals in fluvial-fan successions must be carefully evaluated to improve the reliability of source-to-sink models and palaeodrainage reconstructions, as autogenically controlled noise can be generated during the dispersal of detrital zircon in fluvial sedimentary systems.</p>","PeriodicalId":54144,"journal":{"name":"Depositional Record","volume":"11 2","pages":"511-536"},"PeriodicalIF":1.9,"publicationDate":"2024-10-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/dep2.316","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143846250","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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":"Facies variations in gravelly cyclic steps deposited from turbidity currents: Miocene fan delta front deposits compared with a modern active fan delta, central Japan","authors":"Takeshi Nakajima, Yoshiki Saito","doi":"10.1002/dep2.315","DOIUrl":"https://doi.org/10.1002/dep2.315","url":null,"abstract":"<p>Gravelly cyclic steps formed by turbidity currents have recently been widely recognised in the geological record. However, the comparison between modern and ancient gravelly cyclic steps remains challenging. In this study, the facies variations of gravelly cyclic steps deposited from turbidity currents in an outcrop of Miocene fan delta front deposits in central Japan are compared with the geomorphic evolution of analogous cyclic steps on the active fan delta front in modern geological systems. These cyclic steps share common characteristics in setting, grain size and dimensions, allowing direct comparison between ancient and modern examples. Repeat bathymetric surveys of the modern Kurobe River fan delta have revealed various types of upslope migrating bedforms interpreted as cyclic steps. Most of these are short-lived due to erosion of thalwegs by powerful surge-type turbidity currents triggered by slope failures or burial of thalwegs by deposition, possibly from river-fed hyperpycnal flows. Such erosion and burial events occur annually on the fan delta front, resulting in compensational cycles. Sedimentary facies of the Miocene fan delta front deposits include conglomerate with a gently upslope dipping erosional base, backset-stratified sandstone and foreset-stratified sandstone, which are interpreted as deposits of hydraulic jumps in high-density turbidity currents in scours on the stoss sides of cyclic steps. Parallel-stratified conglomerate sandstone is an additional component. Although previous facies models of gravelly cyclic steps have focussed on deposits on stoss sides, a comparison of modern and ancient examples suggests that facies on the lee sides could be parallel-stratified conglomerate sandstone and undulating bedforms, reflecting supercritical flow conditions. The present study also suggests that hyperpycnal and surge-type high-density turbidity currents may deposit different types of facies and play different roles in the construction and destruction of cyclic steps. The present study has significant implications for facies models of gravelly cyclic steps.</p>","PeriodicalId":54144,"journal":{"name":"Depositional Record","volume":"11 2","pages":"490-510"},"PeriodicalIF":1.9,"publicationDate":"2024-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/dep2.315","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143845993","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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":"Description of the Late Holocene South-east Saline Everglades, Florida palustrine depositional environment with comparisons to other Holocene environments","authors":"John F. Meeder","doi":"10.1002/dep2.314","DOIUrl":"https://doi.org/10.1002/dep2.314","url":null,"abstract":"<p>A transgressive palustrine depositional model is described for the South-east Saline Everglades, Florida. The origin, development and termination of freshwater carbonate mud (marl) deposition along the very low gradient Late Pleistocene carbonate ramp are responses to changing rates of rising sea level during the Late Holocene. The onset of the Late Holocene is defined by a decrease in the rate of sea-level rise from between 2 and 3 to <1 mm year<sup>−1</sup>. Freshwater marl deposition began with this decrease <i>ca</i> 3165 ± 187 year BP, in a shallow (<0.3 m deep), ephemeral wetland that developed landward of a fringing mangrove forest and is maintained by seasonal Everglades water delivery. Sedimentation kept pace with sea-level rise forming a 1.2 m thick wedge shaped, landward thinning deposit. The rate of global sea-level rise began to accelerate <i>ca</i> 1900, the Anthropocene Marine Transgression, and presently the regional rate is 9.4 mm year<sup>−1</sup>. Saltwater encroachment rates >80 m year<sup>−1</sup> are driven by sea-level rise. Saltwater encroachment resulted in retreat and transformation of coastal communities and their biogenic facies, resulting in a decrease in freshwater wetlands and marl production. Inundation ponding, mangrove overstep and the beginning of submergence are the responses to the accelerating rate of sea-level rise, however, small scale topographic and tidal ingress differences create considerable variability between Biscayne Bay and Florida Bay coastal basins. The freshwater marl producing habitat will probably be lost within 55 years, and submergence within the next century at the present rate of sea-level rise. The unique South-east Saline Everglades depositional environment is compared to other Holocene palustrine depositional environments.</p>","PeriodicalId":54144,"journal":{"name":"Depositional Record","volume":"11 1","pages":"467-485"},"PeriodicalIF":1.9,"publicationDate":"2024-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/dep2.314","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143446897","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Reyhan Kara Gülbay, Merve Özyurt, Sadettin Korkmaz
{"title":"Sedimentary factors controlling the organic matter enrichment in oil shale, Seyitömer Lacustrine Basin, Western Anatolia: New implications from organic and inorganic geochemistry","authors":"Reyhan Kara Gülbay, Merve Özyurt, Sadettin Korkmaz","doi":"10.1002/dep2.313","DOIUrl":"https://doi.org/10.1002/dep2.313","url":null,"abstract":"<p>Western Anatolia, an important segment of the Alp-Himalayan Belt, hosts numerous Neogene lacustrine basins with potential oil shale reserves surpassing 1.6 billion tonnes. Among these basins, the Seyitömer Basin (Kütahya) stands out, containing oil shales that are intercalated with claystone, marl, limestone and coal layers. This study presents a comprehensive dataset of organic and inorganic chemistry to gain insight into the palaeoclimate and palaeoenvironmental factors that control the enrichment of organic matter. The studied samples exhibit high total organic carbon contents, averaging 12.85% (ranging from 2.22 to 36.21%), high hydrogen indices (486–812 mgHC/g rock) and low oxygen indices (33–70 mgCO<sub>2</sub>/g total organic carbon), indicating their substantial hydrocarbon-source potential. These characteristics indicate predominantly ‘excellent’ to occasionally ‘very good’ source rock qualities and very high oil potential. Their pyrolysis, gas chromatography and gas chromatography–mass spectrometer parameters indicate an immature-early mature characteristic for Seyitömer oil shale samples. They comprise dominantly Type-I kerogen with minor Type-II kerogen and lacustrine algal organic matter. Their sedimentological characteristics, along with various geochemical values, such as total organic carbon versus S, B versus Ga and dibenzothiophene/phenanthrene, reveal a moderately deep fresh/brackish to saline lacustrine environment. The Ga/Rb, K/Al and Sr/Cu ratios suggest dominantly humid and warm climate conditions, occasionally interrupted by periods of less humidity. The prevalence of warm and humid climate conditions leads to intense chemical weathering processes, supported by high Chemical Index of Alteration and low Rb/Sr ratios in the associated oil shale samples. Intense chemical weathering and high runoff resulted in dissolved nutrient enrichment, promoting ecological dynamics favourable to increased productivity. Their low Pr/Ph and Mo/total organic carbon ratios, high Ni/Co ratio and, relatively low Mo<sub>EF</sub>/U<sub>EF</sub> ratio, along with well-developed lamination of the oil shales, indicate the presence of anoxic conditions in the bottom water. These anoxic conditions would have facilitated the preservation potential of organic matter in the samples. Thus, the palaeoclimate conditions integrated with sedimentary factors have an important role in the ecological dynamic and physical–chemical environmental conditions, ultimately contributing to the organic matter enrichment of the studied samples. This work provides a case study to better understand the sedimentary factors controlling organic matter enrichment in the lacustrine basins of the Alp-orogenic belt.</p>","PeriodicalId":54144,"journal":{"name":"Depositional Record","volume":"11 1","pages":"444-466"},"PeriodicalIF":1.9,"publicationDate":"2024-10-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/dep2.313","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143446988","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Alexandrea Arnold, John Mering, Lauren Chari, Cristian Román-Palacios, Huashu Li, Victoria Petrys,hyn, Bryce Mitsunaga, Ben Elliott, John Wilson, Jamie Lucarelli, Ronny Boch, Daniel Ibarra, Lin Li, Majie Fan, Darrell Kaufman, Andrew Cohen, Rob Dunbar, James Russell, Stefan Lalonde, Priyadarsi D. Roy, Martin Dietzel, Xingqi Liu, Fengming Chang, Robert A. Eagle, Aradhna Tripati
{"title":"Comparative clumped isotope temperature relationships in freshwater carbonates","authors":"Alexandrea Arnold, John Mering, Lauren Chari, Cristian Román-Palacios, Huashu Li, Victoria Petrys,hyn, Bryce Mitsunaga, Ben Elliott, John Wilson, Jamie Lucarelli, Ronny Boch, Daniel Ibarra, Lin Li, Majie Fan, Darrell Kaufman, Andrew Cohen, Rob Dunbar, James Russell, Stefan Lalonde, Priyadarsi D. Roy, Martin Dietzel, Xingqi Liu, Fengming Chang, Robert A. Eagle, Aradhna Tripati","doi":"10.1002/dep2.312","DOIUrl":"https://doi.org/10.1002/dep2.312","url":null,"abstract":"<p>Lacustrine, riverine and spring carbonates represent archives of terrestrial climates and their geochemistry has been used to study palaeoenvironments. Clumped isotope thermometry is an emerging tool that has been applied to freshwater carbonates. Limited work has been done to evaluate comparative relationships between clumped isotopes and temperature in different types of modern freshwater carbonates. This study assembles an extensive calibration data set with 135 samples of modern freshwater carbonates from 96 sites and constrains the relationship between independent observations of water temperature and the clumped isotopic composition of carbonates (denoted by Δ<sub>47</sub>), including new measurements, and recalculates published data in accordance with current community-defined standard values. For temperature reconstruction, the study reports a composite freshwater calibration and material-specific calibrations for biogenic carbonates (freshwater gastropods and bivalves), fine-grained carbonate (e.g. micrites), biologically mediated carbonates (microbialites and tufas) and travertines. Material-specific calibration trends show a convergence of slopes that are in agreement with recently published syntheses, but statistically significant differences in intercepts occur between some materials (e.g. some biogenics, fine-grained carbonates). These differences may arise due to unresolved seasonal biases, kinetic isotope effects and/or varying degrees of biological influence. The impact of different calibrations is shown through application to new data for glacial and deglacial age travertines from Austria and published data sets. While material-specific calibrations may yield more accurate results for biogenic and fine-grained carbonate samples, the use of material-specific and the composite freshwater calibrations generally produces values within 1.0–1.5°C of each other, and typically fall within calibration uncertainty given limitations of precision.</p>","PeriodicalId":54144,"journal":{"name":"Depositional Record","volume":"11 1","pages":"418-443"},"PeriodicalIF":1.9,"publicationDate":"2024-10-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/dep2.312","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143446989","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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":"The role of organic matter in Brazilian Pre-Salt carbonates","authors":"Ilana Lehn, Crisógono de Oliveira Vasconcelos","doi":"10.1002/dep2.311","DOIUrl":"https://doi.org/10.1002/dep2.311","url":null,"abstract":"<p>Diverse types of organic matter morphology were identified in Brazilian Pre-salt carbonates. Stromatolites and laminated facies contain organic layers, filaments and rounded features inside calcite structures, as shrubs and spherulites. Analyses with optical and fluorescent microscopy, scanning electron microscopy with energy-dispersive X-ray spectroscopy, and ion mass spectrometry indicate the presence of organic compounds in thin sections. Fluorescent microscopy shows a high signal for organic portions in the thin section, mainly inside calcite structures and within the matrix. Scanning electron microscopy with energy-dispersive X-ray spectroscopy elemental mapping indicates the presence of carbon in the stromatolite facies, associated either with calcium and oxygen, indicating carbonate, or isolated from other elements, representing carbon content in the samples. The presence of organic matter along and inside calcite structures indicate a strong microbial influence in Brazilian Pre-Salt carbonates precipitation. The purpose of this research is to show that the presence of organic matter is connected to the process of carbonate precipitation and/or dissolution. The occurrence of these organic compounds in distinguishing facies raises the discussion of biotic versus abiotic genesis of the Pre-salt lacustrine reservoirs.</p>","PeriodicalId":54144,"journal":{"name":"Depositional Record","volume":"11 1","pages":"403-417"},"PeriodicalIF":1.9,"publicationDate":"2024-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/dep2.311","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143446795","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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":"The early–middle Cambrian siliciclastic tide-dominated succession in eastern Korea","authors":"Min-Kyu Oh, Taejin Choi, Jeong-Hyun Lee","doi":"10.1002/dep2.310","DOIUrl":"https://doi.org/10.1002/dep2.310","url":null,"abstract":"<p>The basal Taebaek Group (Myeonsan and Myobong formations) illustrates second-order transgression on the eastern Sino-Korean Block during the early–middle Cambrian (Stage 3?–Wuliuan). The irregular palaeotopography of Precambrian basement led to the development of localised alluvial fans and fan deltas. As transgression continued, tidally influenced estuarine and associated shallow subtidal flats developed. Continued transgression resulted in a relatively deep subtidal environment, with postulated carbonate shoals serving as barriers. Stacking of facies indicates a general deepening-upward trend, transitioning from terrestrial–nearshore to marine environments dominated by tidal effects. The study area subsequently experienced shallowing, leading to the emergence of tidal inlet and dune environments. Siliciclastic input was attenuated, facilitating the development of carbonate shoal complexes. The overall transgressive succession of the basal Taebaek Group aligns with similar sequences observed in the Sino-Korean Block and western Laurentia, where the lowermost Cambrian strata which formed in various depositional environments on the uneven basement rocks were followed by extensive tide-dominated siliciclastic successions. These successions were then overlain by epeiric carbonate platforms that developed synchronously across the area as siliciclastic input diminished with the continued transgression. This comparison demonstrates that the transgressive sequences in the Sino-Korean Block and western Laurentia can be understood within a framework that explains how extensive Cambrian carbonate platforms initially developed due to a second-order eustatic sea-level rise during the Cambrian greenhouse period.</p>","PeriodicalId":54144,"journal":{"name":"Depositional Record","volume":"10 4","pages":"441-466"},"PeriodicalIF":1.9,"publicationDate":"2024-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/dep2.310","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142273093","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Carys Lock, Miranda Reid, Jaco H. Baas, Jeff Peakall
{"title":"Preservation of groove mark striae formed by armoured mud clasts: The role of armour sediment size and bed yield stress","authors":"Carys Lock, Miranda Reid, Jaco H. Baas, Jeff Peakall","doi":"10.1002/dep2.309","DOIUrl":"https://doi.org/10.1002/dep2.309","url":null,"abstract":"<p>Striated grooves in tool marks are common at the base of sandstones, especially in deep-marine successions, but their use in physical-process and environmental reconstruction is underdeveloped. To fill this gap in knowledge, striations in the central groove of chevron marks and in chevron-less groove marks were formed in the laboratory by dragging tools armoured with silt, sand or gravel across muddy substrates. These experiments simulated the formation of striated grooves by armoured mud clasts carried at the base of quasi-laminar and fully laminar debris flows, aiming to: (1) delineate the bed shear strengths for the formation of striated grooves at different armour sediment sizes; (2) examine how the preservation potential of striated grooves depends on clay bed rheology and size of armour sediment and (3) discuss how the pre-lithification clay bed consolidation state and size of armour sediment can be reconstructed from striated grooves in the geological record. The experimental results revealed that tools with small-diameter silt and sand armours dragged along soft beds lack striations or, at best, leave poorly defined striations, whereas firm beds and gravel armours exhibit well-defined striations. The spacing of striations formed by gravel clasts corresponds well with the clast diameter, implying that striation spacing is a good proxy for the diameter of armoured gravel under natural conditions. In contrast, the spacing of striae formed by sand armours is greater than the grain diameter, suggesting that the spacing of fine striations can only be used to predict a maximum armour sand size. A comparison of different processes of formation of armoured mud clasts demonstrated that the armouring of mud clasts most probably happens after incorporation of the clasts by erosion into the head of the debris flow and subsequent movement across a loose sandy or gravelly bed surface.</p>","PeriodicalId":54144,"journal":{"name":"Depositional Record","volume":"10 4","pages":"426-440"},"PeriodicalIF":1.9,"publicationDate":"2024-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/dep2.309","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142273147","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}