Depositional Record最新文献

{"title":"Application of micro-CT to resolve textural properties and assess primary sedimentary structures of deep-marine sandstones","authors":"P. H. Cornard,&nbsp;G. Degenhart,&nbsp;P. Tropper,&nbsp;J. Moernaut,&nbsp;M. Strasser","doi":"10.1002/dep2.261","DOIUrl":"10.1002/dep2.261","url":null,"abstract":"<p>Over the past decade, there has been growing interest in the sedimentological community to use micro X-ray computed tomography to analyse microfacies in sediment cores. However, little attention has been paid to the application of micro-computed tomography in lithified deposits, even though this can allow their texture to be characterised in three dimensions, providing key information about sedimentary structures. A novel application of micro-computed tomography in lithified sediment-gravity flow deposits is presented with the objective of characterising their internal 3D sedimentary structures. This technique is applied to three deep-marine sandstones showing different compositional properties: Cretaceous Gosau Group (Austria), Eocene Hecho Group (Spain) and the Oligocene Annot Formation (France). From micro-computed tomography data the size of particles and their distribution throughout the sample is reconstructed in 3D permitting a better visualisation of sedimentary textures. Particle distributions computed from micro-computed tomography are similar to those computed from thin section image analysis, corroborating the reliability of the micro-computed tomography to evaluate grain-size trends. Micro-computed tomography is complemented with micro-X-ray fluorescence and thin section petrographic analyses. In cases where mineral composition or grain size are homogeneous or matrix and grains have similar mineral composition, sedimentary structures do not appear visible from micro-X-ray fluorescence or thin section analyses. By separating particles based on their computed tomography density, it is possible to isolate the coarsest fraction, highlighting the sedimentary structures. This study demonstrates (i) the potential of micro-computed tomography in analyses of sedimentary structures from outcrop data and (ii) the importance of the mineralogical composition and degree of grain sorting in assessing the origin of structureless deposits. Considering the importance of visualising sedimentary structures when interpreting depositional processes, micro-computed tomography is a new and reliable tool to assess the physical properties of sandstones and to analyse their internal 3D sedimentary structures.</p>","PeriodicalId":54144,"journal":{"name":"Depositional Record","volume":"10 5","pages":"559-580"},"PeriodicalIF":1.9,"publicationDate":"2023-12-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/dep2.261","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139180994","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":"Biogenicity of amorphous organic matter and bacteriomorph acritarchs preserved in wrinkle structures from the Ediacaran Cíjara Formation, Spain","authors":"J. Javier Álvaro,&nbsp;José E. Ortiz,&nbsp;Carlos Neto de Carvalho,&nbsp;Ignacio López-Cilla,&nbsp;Yolanda Sánchez-Palencia,&nbsp;Trinidad Torres","doi":"10.1002/dep2.258","DOIUrl":"10.1002/dep2.258","url":null,"abstract":"<p>Establishing the biogenicity of sedimentary surface textures with unresolved microbial origin is critical to any environmental and geobiological interpretation of clastic settings. Here, some Ediacaran wrinkle structures and associated carbonaceous greywacke samples containing mat fragments rich in ‘bacteriomorph acritarchs’ are investigated. Their biogenicity was evaluated with transmitted light and scanning electron microscopy, epifluorescence and Raman spectroscopy, and confirmed by the presence of distinct cyanobacterial biomarkers. The comparison of results yielded by these techniques validates the use of Raman spectroscopy on Neoproterozoic kerogen (organic-walled microfossils and amorphous organic material) under low metamorphic conditions. Raman spectrographs also allowed recognition of associated rare-earth element-rich phosphate (monazite) and subsidiary metal sulphide concentrations, and interpreted as a result of biosorption and/or mat trapping under normal oxic conditions. These microbial mat features represent cyanobacterial bloom-forming <i>Bavlinella</i> acritarchs, which characterise eutrophic episodes in a semi-enclosed retroarc basin sandwiched between an active Cadomian arc and West Gondwana.</p>","PeriodicalId":54144,"journal":{"name":"Depositional Record","volume":"10 1","pages":"51-69"},"PeriodicalIF":2.4,"publicationDate":"2023-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/dep2.258","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139183546","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":"Sequence stratigraphical and palaeoenvironmental implications of Cenomanian–Santonian dinocyst assemblages from the Trans-Sahara epicontinental seaway: a multivariate statistical approach","authors":"Musa B. Usman,&nbsp;David W. Jolley,&nbsp;Alexander T. Brasier,&nbsp;Adrian J. Boyce","doi":"10.1002/dep2.260","DOIUrl":"10.1002/dep2.260","url":null,"abstract":"<p>The Cretaceous was punctuated by episodic flooding of continental margins forming epicontinental seas. The Trans-Sahara Seaway was one of these epicontinental seas, connecting the Gulf of Guinea with the Tethys Ocean. In this study, data including microplankton abundances, stable carbon isotopes of organic material and elemental geochemistry were integrated with traditional sedimentological analyses from the Trans-Sahara Seaway. The carbon isotopic data provide the first evidence that oceanic anoxic event 2 was present in the Trans-Sahara Seaway, and palynology shows it was associated with an increase in peridinioid dinocyst abundance. A combined study of microplankton assemblages and sedimentology reveals palaeoenvironmental trends linked to sea-level change. Lowstand system tracts were characterised by increased siliciclastic grain size, low microplankton diversity, and were dominated by Chlorophyceae. Transgressive system tracts were associated with diversity increases during rising sea level, with open marine gonyaulacoid dinocysts dominating the assemblages. Maximum flooding surfaces were recognised by the highest increase in biological diversity in argillaceous deposits. As sea level started to fall, the peridinioid dinocysts became dominant, with decreased microplankton diversity during highstand systems tracts. This combination of sedimentology and interpretation of dinocyst assemblages allows the identification of shallow to deeper marine depositional sequences of Cenomanian–Santonian strata within the Yola Sub-basin. This approach could be used to delineate marine depositional sequences where using conventional sedimentological methods alone is very challenging.</p>","PeriodicalId":54144,"journal":{"name":"Depositional Record","volume":"10 1","pages":"91-123"},"PeriodicalIF":2.4,"publicationDate":"2023-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/dep2.260","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139183549","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":"Flow dynamics as Froude-supercritical turbidity currents encounter metre-scale slope minibasin topography","authors":"Rebecca G. Englert,&nbsp;Stephen M. Hubbard,&nbsp;Brian W. Romans,&nbsp;Sebastian Kaempfe,&nbsp;Daniel Bell,&nbsp;Paul R. Nesbit,&nbsp;Lisa Stright","doi":"10.1002/dep2.262","DOIUrl":"https://doi.org/10.1002/dep2.262","url":null,"abstract":"<p>Seafloor topography can affect turbidity current dynamics on deep-water slopes, significantly influencing the dispersal of sediment. Despite the common occurrence of topographic complexity, there are few detailed investigations of topographic interactions and their effect on downslope flow evolution in intraslope environments. In this study, the sedimentology and architecture of an Upper Cretaceous intraslope fan succession deposited within an extensional, fault-bound minibasin are described from a rare, well-exposed, near-continuous, oblique depositional-dip outcrop of the Tres Pasos Formation, Chile. The 2 to 8 m thick studied interval transitions downslope from high-energy heterolithic strata, including metre-scale steep-faced scours, to non-amalgamated thick-bedded sandstones. Abrupt increases in sandstone percentage, sandstone bed thickness and grain size occur on the hangingwall blocks of south-east and north-east-dipping normal faults that bound the minibasin. Sandstone beds are dominated by backset or wavy low-angle stratification proximally, contain compositional banding near faults, and are characterised by increased proportions of planar laminated and structureless turbidite divisions downslope along the transect. Experimental observations of turbidity current interactions with topography are synthesised into a qualitative framework, which is used to interpret flow processes and characteristics from deposit trends. The results reconstruct the response of Froude-supercritical, stratified turbidity currents with denser basal layers when encountering metre-scale fault scarps. The analysis shows that metre-scale topographic features can substantially alter the flow properties of stratified turbidity currents, and their downslope flow evolution to include the development of transitional, depositional and flow-stripped sediment gravity currents. However, in comparison to base-of-slope settings, overall flow conditions are interpreted to be more uniform over slope breaks and zones of flow expansion in a partially confined intraslope environment. These findings have considerable implications for understanding flow response to similar scale morphological features on the seafloor and the potential for flow transformations in intraslope settings.</p>","PeriodicalId":54144,"journal":{"name":"Depositional Record","volume":"10 5","pages":"527-558"},"PeriodicalIF":1.9,"publicationDate":"2023-12-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/dep2.262","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142685305","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":"Characterising the heterogeneous nature of tufa mounds by integrating petrographic, petrophysical, acoustic and electromagnetic measurements","authors":"S. Schröder,&nbsp;J. P. Corella,&nbsp;X. M. Pellicer,&nbsp;P. Rook,&nbsp;A. Kara,&nbsp;X. Comas","doi":"10.1002/dep2.259","DOIUrl":"10.1002/dep2.259","url":null,"abstract":"<p>Determination of the physical properties of subsurface geological bodies is essential for georesource management and geotechnical applications. In the absence of direct measurements, this usually passes via geophysical methods such as seismic and ground-penetrating radar. These require conversion to physical properties, and measurements at different scales to test for consistency. This approach is non-trivial in geobodies with heterogeneous patterns of properties. Tufa mounds—in-situ terrestrial carbonate buildups precipitating from geothermal waters—are characterised by high contrasts in facies and petrophysical properties from microscale to macroscale, and are therefore ideally suited to test the ability of non-invasive geophysical methods to estimate such contrasts, and to develop petrophysical models based on geophysical properties. Here, a laboratory-based study of a Pleistocene tufa mound in Spain is presented that combines (1) petrography, (2) digital 2D pore network analysis, (3) gas porosity and permeability measurements, (4) acoustic velocity measurements and (5) electromagnetic wave velocity and porosity determination from ground-penetrating radar, to develop empirical petrophysical models. These results show the consistency of petrophysical properties determined with different methods across various observational scales. Electromagnetically derived porosity positively correlates with gas porosity. Petrophysical properties depend on measurable rock fabric parameters and the degree of cementation, which provide predictive tools for subsurface geobodies. Strongly cemented peloidal-thrombolitic fabrics with intergranular and intercrystalline pores, and a dominance of small complex pores best transmit acoustic waves. Weak cementation and a significant fraction of large simple pores (framework, vegetation moulds) increase porosity and permeability of shrubby fabrics, while causing lower acoustic velocity. This study demonstrates that ground-penetrating radar models can be used in combination with direct measurements of physical subsurface properties to capture highly contrasting physical properties associated with different sedimentary facies that would not be achievable with other methods, thus improving the understanding of formational processes.</p>","PeriodicalId":54144,"journal":{"name":"Depositional Record","volume":"10 1","pages":"70-90"},"PeriodicalIF":2.4,"publicationDate":"2023-11-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/dep2.259","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139254383","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":"Testing geological proxies for deep-time tidal model simulations","authors":"B. Guo,&nbsp;L. A. M. Fitzgerald,&nbsp;J. M. Hewitt,&nbsp;O. Pampaloni,&nbsp;J. A. M. Green","doi":"10.1002/dep2.256","DOIUrl":"10.1002/dep2.256","url":null,"abstract":"<p>Tides are a key driver of a range of Earth system processes, and we now have the capacity to simulate tidal dynamics on a range of temporal and spatial scales. Deep-time tidal model simulations have been used to provide insight into past ocean circulation patterns, evolution of life and the developments of the Earth-Moon system's orbital configuration. However, these tidal model simulations are relatively poorly constrained and validated because of a lack of readily available proxies. The feasibility of using two types of proxy is explored here; (1) sedimentary deposits which can directly estimate palaeotidal ranges, and (2) black shale, to constrain three palaeotidal model simulations for different time slices. Specifically, three palaeotidal range proxies were used for the early Devonian (400 Ma), three palaeotidal range proxies and five black shales for the lower Jurassic (185 Ma), and eight black shales for the early Cretaceous (95 Ma). Both tidal proxies confirm the tidal model results in most locations. The model results for 400 Ma and 185 Ma matched 2/3 of the palaeotidal range proxies for each of these periods. The locations of black shale were compared with tidal front locations predicted by the model outputs based on the Simpson–Hunter parameter and the model results from 95 to 185 Ma agree with the black shale proxies in 10/13 of the locations. In the cases where there is a disagreement, the model resolution is probably too low to fully resolve the details of the coastal topography, or—in one case—the palaeobathymetry is incorrect. Consequently, it is argued that it is worth expanding this type of work, and that such data can be used to validate both models and reconstructions.</p>","PeriodicalId":54144,"journal":{"name":"Depositional Record","volume":"10 5","pages":"515-526"},"PeriodicalIF":1.9,"publicationDate":"2023-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/dep2.256","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135889007","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 origin of planar lamination in fine-grained sediment deposited by subaqueous sediment gravity flows","authors":"Omar N. Al-Mufti,&nbsp;R. William C. Arnott","doi":"10.1002/dep2.257","DOIUrl":"10.1002/dep2.257","url":null,"abstract":"<p>Planar lamination is a ubiquitous component of modern and ancient fine-grained sediments deposited by subaqueous sediment gravity flows. These sediments commonly exhibit alternating sub-millimetre-thick, sharply bounded silt-rich and clay-rich layers that change little in thickness or sediment texture over lateral distances that range up to at least several tens of metres. Silt-rich layers are moderately to well-sorted and a few tens to hundreds of microns to a single silt-grain thick. In contrast, clay-rich layers are more poorly sorted, and a few tens to hundreds of microns thick. The thickness and regular alternation of these texturally differentiated interlayers, in addition to the absence of features suggesting transport bypass or deposition by migrating rugged bed forms, suggest alternating physical processes and related modes of deposition in the near-bed region immediately above the bed. Previous interpretations have focussed on clay flocculation, which is difficult to reconcile with the high fluid shear conditions in the near-bed region. Here it is suggested that in the millimetre to sub-millimetre-thick viscous sublayer at the base of a hydraulically smooth turbulent flow, a combination of high fluid shear and sediment concentration initially leads to shear thinning and enhanced mobility in the lower part of the flow, and for silt to continue settling to the bed forming a well-sorted silt lamina. As silt settles and clay-size sediment increases in concentration, hydrodynamic lubrication forces strengthen and reduce mobility of the near-bed part of the flow. This condition is then perturbed by a bedward-directed outer flow disturbance that dramatically increases frictional stresses and effective fluid viscosity and ultimately shear jamming that causes gelling and deposition of a poorly sorted clay-rich layer. This process is then repeated multiple times to build up a deposit composed of alternating silt-rich and clay-rich laminae overlain by structureless mud deposited directly from suspension.</p>","PeriodicalId":54144,"journal":{"name":"Depositional Record","volume":"10 5","pages":"496-514"},"PeriodicalIF":1.9,"publicationDate":"2023-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/dep2.257","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135758764","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":"An integrated petrographical and geochemical study of the Tredian Formation in the Salt and Trans-Indus Surghar ranges, North-West Pakistan: Implications for palaeoclimate","authors":"Kamil Ahmed Qureshi,&nbsp;Muhammad Rizwan,&nbsp;Hammad Tariq Janjuhah,&nbsp;Ihtisham Islam,&nbsp;George Kontakiotis,&nbsp;Ahmer Bilal,&nbsp;Mohamad Arif","doi":"10.1002/dep2.255","DOIUrl":"10.1002/dep2.255","url":null,"abstract":"<p>The Middle Triassic Tredian Formation is well exposed in the western region of the Salt Range. It is mostly composed of sandstone with minor alternations of shales and dolomite. This is the first integrated attempt using petrographical and geochemical features to reveal palaeoclimate during deposition of the Tredian Formation. This work sheds light on the petrographical and geochemical properties of the Tredian sandstone in order to date various layers and evaluate the palaeoclimate. The formation was sampled at two distinct stratigraphic layers for petrographic and geochemical analysis of major and trace elements. The sandstone of the Tredian Formation is sub-feldspathic to feldspathic arenite with sub-angular to rounded grains that are moderately to extensively sorted. The relative proportions of the quartz, feldspars and lithoclasts in the examined sandstone samples shows that the Tredian sediments originated from the interior of the craton during a transitional continental regime. Chemical index of alteration values of 59, chemical index of weathering values of 67, and plagioclase index of alteration values of 74.5 indicate a low to moderate degree of weathering in the Tredian sediment source region. Based on the silica content, SiO₂/Al₂O₃ ratios (2.7–6.1; mean 4.1), and chemical maturity index, it is deduced that the Tredian Formation was deposited in chemically immature to sub-mature and dry to semi-arid conditions. Geochemical proxies indicate the acidic source of sediment and deposition on the passive margin of the Indian Plate. The trace element characteristics of the sediments, especially the Rb/Sr, Cu/Zn, Ni/Co, V/Cr and Sr/Ba ratios, indicate that the sediments originated from the first weathering cycle and support the notion that they were deposited in an oxidising continental environment. A semi-arid to arid palaeoclimate predominated through the Middle Triassic at the north-western passive continental margin of the Indian Plate in the south-eastern Neo-Tethys.</p>","PeriodicalId":54144,"journal":{"name":"Depositional Record","volume":"10 1","pages":"33-50"},"PeriodicalIF":2.4,"publicationDate":"2023-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/dep2.255","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135758628","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":"Discussion on ‘Middle Jurassic multi-scale transgressive–regressive cycles: An example from the Lusitanian Basin’, by Magalhães et al., Depositional Record, 2023, 9(1), 174–202","authors":"Ana C. Azerêdo,&nbsp;Vânia F. Correia,&nbsp;Ángela Fraguas","doi":"10.1002/dep2.252","DOIUrl":"10.1002/dep2.252","url":null,"abstract":"&lt;p&gt;The paper by Magalhães et al. (&lt;span&gt;2023&lt;/span&gt;) concerns the Jurassic coastal outcrop between Consolação and São Bernardino beaches, in the western-central Lusitanian Basin (LB), Portugal (Figure 1). The authors used a sequence stratigraphic approach, defining multi-scale cycles and, based on nannofossils and dinoflagellate cysts (dinocysts) data, they re-assigned the section to the Middle Jurassic ‘Candeeiros Formation’; formerly the section had been established as part of the Upper Jurassic Alcobaça Formation (namely Fürsich et al., &lt;span&gt;2022&lt;/span&gt;; Leinfelder, &lt;span&gt;1986&lt;/span&gt;; Manuppella et al., &lt;span&gt;1999&lt;/span&gt;; Schneider et al., &lt;span&gt;2009&lt;/span&gt;; Werner, &lt;span&gt;1986&lt;/span&gt;). Although the sedimentology and sequence analysis were detailed, we consider their assessment to be incorrect and oversimplified including, for example, the assigned age of the unit and the top of the section. Moreover, the new fossil data are too briefly discussed and based on limited data, and the local/regional geology is barely discussed.&lt;/p&gt;&lt;p&gt;The Alcobaça Formation, recently formalised by Fürsich et al. (&lt;span&gt;2022&lt;/span&gt;), is an important unit of the Upper Jurassic of the LB (Figure 2). Fürsich et al. (&lt;span&gt;2022&lt;/span&gt;) provided an extensive literature overview, in which the formation is thoroughly described, illustrated and correlated within the basin (including the Consolação section); they presented facies analysis, macropalaeontological and micropalaeontological taxonomic and palaeoecological data and palaeogeographical interpretations. However, this seminal work is not mentioned by Magalhães et al. (&lt;span&gt;2023&lt;/span&gt;). The Alcobaça Formation is a mixed siliciclastic-carbonate succession; its age is constrained by macrofossil and microfossil data and strontium isotope values, and has been confidently considered to be mainly of Kimmeridgian age, although possible slight age extensions of its base and top have been discussed (Fürsich et al., &lt;span&gt;2022&lt;/span&gt;; Kullberg &amp; Rocha, &lt;span&gt;2014&lt;/span&gt;; Leinfelder, &lt;span&gt;1986&lt;/span&gt;; Manuppella et al., &lt;span&gt;1999&lt;/span&gt;; Schneider et al., &lt;span&gt;2009&lt;/span&gt;; Werner, &lt;span&gt;1986&lt;/span&gt;).&lt;/p&gt;&lt;p&gt;If the part of the section described by Magalhães et al. (&lt;span&gt;2023&lt;/span&gt;) were Middle Jurassic strata, then the local succession would be: the outcrops of Kimmeridgian Alcobaça Formation at the Consolação section, succeeded southwards by the Middle Jurassic (Bathonian/Callovian) ‘Candeeiros Formation’, in turn overlain by the much later Upper Jurassic Lourinhã Formation, the intervening units locally (and implausibly) not present. No considerations of plausible depositional geometries or regional correlations with nearby formations were made to support the drastic sequence changes implied.&lt;/p&gt;&lt;p&gt;At Cesareda zone, about 9 km eastwards, and at Baleal Peninsula, about 7 km north-westwards (Figure 1), Middle Jurassic carbonate outcrops occur, dated by ammonites from, respectively, Bajocian to Callovian and Bajocian/Bath","PeriodicalId":54144,"journal":{"name":"Depositional Record","volume":"9 4","pages":"1153-1160"},"PeriodicalIF":2.4,"publicationDate":"2023-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/dep2.252","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134947438","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":"Comment on: Magalhães et al., Middle Jurassic multi-scale transgressive–regressive cycles: An example from the Lusitanian Basin, The Depositional Record, 9, 174–202","authors":"S. Schneider,&nbsp;F. T. Fürsich,&nbsp;W. Werner,&nbsp;C. S. Pierce","doi":"10.1002/dep2.253","DOIUrl":"10.1002/dep2.253","url":null,"abstract":"&lt;p&gt;In a recently published paper, Magalhães et al. (&lt;span&gt;2023&lt;/span&gt;) re-studied the coastal section between the villages of Consolação and São Bernardino south of Peniche, central Portugal, and determined a novel Bathonian to early Callovian age for the exposed strata. They identified low-frequency to high-frequency transgressive–regressive sequences, and interpreted the depositional settings as offshore to shoreface for siliciclastic strata, with subordinate carbonate intervals associated with inner to outer ramp settings. Based on these new results, they assigned the studied strata to the Candeeiros Formation. We show that these conclusions are based on misinterpretation and the non-consideration of previously published contradictory data.&lt;/p&gt;&lt;p&gt;The Jurassic sedimentary succession of the Lusitanian Basin is unusually well-exposed along the Atlantic coast, and offers unique opportunities for study. The coastal section between the villages of Consolação and São Bernardino is a prime example, and has been studied repeatedly (Fürsich et al., &lt;span&gt;2022&lt;/span&gt;; Mateus et al., &lt;span&gt;2017&lt;/span&gt;; Taylor et al., &lt;span&gt;2014&lt;/span&gt;; Werner, &lt;span&gt;1986&lt;/span&gt;), but a modern sequence stratigraphic analysis of this succession has never been attempted. As such, the study of Magalhães et al. (&lt;span&gt;2023&lt;/span&gt;) generally comes as a welcome addition. However, this study falls short in several aspects. Most significantly, its dissonance with previously published contradictory literature is not taken into account, and the interpretation of the data generated is selective and model-driven. We address these issues in the following sections, drawing on the literature, including a recently published study by the present authors (Fürsich et al., &lt;span&gt;2022&lt;/span&gt;), accessible online approximately half a year before the submission of the manuscript of Magalhães et al. (&lt;span&gt;2023&lt;/span&gt;), but not considered in their paper.&lt;/p&gt;&lt;p&gt;Magalhães et al. (&lt;span&gt;2023&lt;/span&gt;) characterise the geodynamic evolution of the Lusitanian Basin in sufficient detail, and the literature cited in this section is relevant and up to date. However, despite the sequence stratigraphic focus of their study, the sedimentological evolution of the basin is barely addressed. In the context of a presumed Middle Jurassic age for the strata at Consolação, it would have been essential to focus on the Early to Middle Jurassic evolution of depositional environments in the Lusitanian Basin, but the lithostratigraphic scheme used is outdated, and numerous key studies are not cited. Magalhães et al. (&lt;span&gt;2023&lt;/span&gt;) use the oversimplified scheme of largely concordant successive Coimbra, Brenha and Candeeiros formations, which was established by Shell Prospex Portuguesa in the 1970s, but never formally published (Witt, &lt;span&gt;1977&lt;/span&gt;). This scheme has been superseded by much more detailed lithostratigraphy. In its revised, restricted sense, the Coimbra Formation of Moitinho de Almeida et al. (&lt;span&gt;19","PeriodicalId":54144,"journal":{"name":"Depositional Record","volume":"9 4","pages":"1161-1166"},"PeriodicalIF":2.4,"publicationDate":"2023-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/dep2.253","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134947439","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}