Pub Date : 2025-01-21DOI: 10.1016/j.pgeola.2024.12.006
Consuelo Sendino , Stephen Kershaw
Sponges of the Lower Greensand Group (LGS) are well preserved and occur in sediments of a sandy matrix. Abundant in the Faringdon Sponge Gravel Member (FSG), these sponges, mostly Calcareans, are found in Oxfordshire, with notable preservation at Little Coxwell quarries. This study provides descriptions of common species following the updated Porifera classification and recent sponge taxonomy research, illustrated with specimens from the Natural History Museum, London (NHM), British Geological Survey (BGS), and Natural History Museum Basel (NMB) collections. The following taxa are recorded and described: 1) Calcareans: Barroisia anastomosans (Parkinson, 1822), Barroisia clavata (Keeping, 1883), Barroisia irregularis (Hinde, 1884), Dehukia crassa (de Fromentel, 1861), [Elasmoierea] faringdonensis (Mantell, 1854), [Elasmoierea] mantelli (Hinde, 1884), Peronidella gillieroni (de Loriol, 1869), Peronidella prolifera (Hinde, 1884), Peronidella ramosa (Roemer, 1839), Oculospongia dilatate (Roemer, 1864), Tremospongia pulvinaria (Goldfuss, 1826), Raphidonema contortum (Hinde, 1884), Raphidonema porcatum (Sharpe, 1854), Raphidonema farringdonensis (Sharpe, 1854), Raphidonema macropora (Sharpe, 1854), Raphidonema pustulatum (Hinde, 1884), Endostoma foraminosa (Goldfuss, 1826); and 2) Hexactinellids: Lonsda contortuplicata (Lonsdale, 1849). Key findings include the identification of Tethyan biogeographic affinities and ecological adaptations that highlight the role of these sponges in early reef-like systems. By refining species descriptions and linking them to broader Cretaceous ecosystems, this work enhances understanding of sponge biodiversity, evolutionary strategies, and their contributions to carbonate platform development during periods of environmental change.
{"title":"A revision of sponges from the Faringdon Sponge Gravel Member and Atherfield Clay Formation, Lower Greensand Group of England","authors":"Consuelo Sendino , Stephen Kershaw","doi":"10.1016/j.pgeola.2024.12.006","DOIUrl":"10.1016/j.pgeola.2024.12.006","url":null,"abstract":"<div><div>Sponges of the Lower Greensand Group (LGS) are well preserved and occur in sediments of a sandy matrix. Abundant in the Faringdon Sponge Gravel Member (FSG), these sponges, mostly Calcareans, are found in Oxfordshire, with notable preservation at Little Coxwell quarries. This study provides descriptions of common species following the updated Porifera classification and recent sponge taxonomy research, illustrated with specimens from the Natural History Museum, London (NHM), British Geological Survey (BGS), and Natural History Museum Basel (NMB) collections. The following taxa are recorded and described: 1) Calcareans: <em>Barroisia anastomosans</em> (Parkinson, 1822), <em>Barroisia clavata</em> (Keeping, 1883), <em>Barroisia irregularis</em> (Hinde, 1884), <em>Dehukia crassa</em> (de Fromentel, 1861), <em>[Elasmoierea] faringdonensis</em> (Mantell, 1854), <em>[Elasmoierea] mantelli</em> (Hinde, 1884), <em>Peronidella gillieroni</em> (de Loriol, 1869), <em>Peronidella prolifera</em> (Hinde, 1884), <em>Peronidella ramosa</em> (Roemer, 1839), <em>Oculospongia dilatate</em> (Roemer, 1864), <em>Tremospongia pulvinaria</em> (Goldfuss, 1826), <em>Raphidonema contortum</em> (Hinde, 1884), <em>Raphidonema porcatum</em> (Sharpe, 1854), <em>Raphidonema farringdonensis</em> (Sharpe, 1854), <em>Raphidonema macropora</em> (Sharpe, 1854), <em>Raphidonema pustulatum</em> (Hinde, 1884), <em>Endostoma foraminosa</em> (Goldfuss, 1826); and 2) Hexactinellids: <em>Lonsda contortuplicata</em> (Lonsdale, 1849). Key findings include the identification of Tethyan biogeographic affinities and ecological adaptations that highlight the role of these sponges in early reef-like systems. By refining species descriptions and linking them to broader Cretaceous ecosystems, this work enhances understanding of sponge biodiversity, evolutionary strategies, and their contributions to carbonate platform development during periods of environmental change.</div></div>","PeriodicalId":49672,"journal":{"name":"Proceedings of the Geologists Association","volume":"136 3","pages":"Article 101091"},"PeriodicalIF":1.2,"publicationDate":"2025-01-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143947765","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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 : 2025-01-17DOI: 10.1016/j.pgeola.2024.12.005
V. Paul Wright , Peter Hodges , Jennifer M. Huggett , Susan B. Marriott
Temporary exposures recording the Upper Triassic–Lower Jurassic transition near Bridgend, South Wales provided a rare opportunity to assess how this major stratigraphical interval is manifested in terrestrial deposits in close proximity to the intensively studied marine and marginal marine successions in SW Britain. Following the progradation and exposure of a shoreline sandbody, up to 8 m of coastal plain deposits formed during a subsequent punctuated transgression. These deposits host a series of palaeosols with unusual carbonate textures, complex mottling styles and marked lateral variability, with evidence of several changes in hydrological conditions. Initially calcrete-bearing soils capped the shoreline sandstones but were overprinted by ferroan-carbonate-bearing gleys likely marking the influence of marine waters. Subsequently, a transition to well-drained soils with calcrete horizons occurred. Continued mud grade deposition was marked by the development of pseudo-gley conditions culminating in gleyed soils, overlain by marine sediments. This provides an example of the often complex polyphase and polygenetic nature of palaeosols encountered in aggrading sedimentary systems.
{"title":"Palaeosols from the Upper Triassic of South Wales","authors":"V. Paul Wright , Peter Hodges , Jennifer M. Huggett , Susan B. Marriott","doi":"10.1016/j.pgeola.2024.12.005","DOIUrl":"10.1016/j.pgeola.2024.12.005","url":null,"abstract":"<div><div>Temporary exposures recording the Upper Triassic–Lower Jurassic transition near Bridgend, South Wales provided a rare opportunity to assess how this major stratigraphical interval is manifested in terrestrial deposits in close proximity to the intensively studied marine and marginal marine successions in SW Britain. Following the progradation and exposure of a shoreline sandbody, up to 8 m of coastal plain deposits formed during a subsequent punctuated transgression. These deposits host a series of palaeosols with unusual carbonate textures, complex mottling styles and marked lateral variability, with evidence of several changes in hydrological conditions. Initially calcrete-bearing soils capped the shoreline sandstones but were overprinted by ferroan-carbonate-bearing gleys likely marking the influence of marine waters. Subsequently, a transition to well-drained soils with calcrete horizons occurred. Continued mud grade deposition was marked by the development of pseudo-gley conditions culminating in gleyed soils, overlain by marine sediments. This provides an example of the often complex polyphase and polygenetic nature of palaeosols encountered in aggrading sedimentary systems.</div></div>","PeriodicalId":49672,"journal":{"name":"Proceedings of the Geologists Association","volume":"136 3","pages":"Article 101090"},"PeriodicalIF":1.2,"publicationDate":"2025-01-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143947764","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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 : 2025-01-17DOI: 10.1016/j.pgeola.2024.12.003
Kirsty M. Edgar , Richard J. Butler , Jonathan G. Larwood , Joshua J.P. Smith
Dinosaur tracks (footprints) provide useful information on the palaeoecology and distribution of dinosaurs over time, complementing the skeletal (body) fossil record. These tracks are amongst the most popular and recognisable trace fossils in the natural world, attracting significant public interest and drawing visitors to sites in England, Scotland, and Wales. Beyond their scientific importance, they offer valuable aesthetic and educational opportunities in the tourism and education sectors. However, the protection, monitoring, communication, and scientific understanding of these sites vary widely. Here we review the nature of the fourteen in-situ dinosaur track sites present in the UK today, and subsequently use an established quantitative system to determine the relative scientific and cultural ‘value’ of each site. We find that the relative scientific and cultural value of UK track sites varies considerably, and that the two value types do not correlate with one another. UK sites with considerable national and international scientific value include the Late Triassic dinosaur track site Bendrick Rock, in South Wales, and the Middle Jurassic site Ardley Quarry, in Oxfordshire. By contrast, the Early Cretaceous dinosaur track sites at Hanover Point, Isle of Wight, and Spyway Quarry, Dorset have relatively high cultural value due to their accessibility and visitor appeal, but modest scientific value. This assessment helps identify threats and opportunities for UK dinosaur track sites, guiding future conservation, scientific research, and public engagement efforts.
{"title":"Determining the relative scientific and cultural “value” of the UK's in-situ dinosaur track sites","authors":"Kirsty M. Edgar , Richard J. Butler , Jonathan G. Larwood , Joshua J.P. Smith","doi":"10.1016/j.pgeola.2024.12.003","DOIUrl":"10.1016/j.pgeola.2024.12.003","url":null,"abstract":"<div><div>Dinosaur tracks (footprints) provide useful information on the palaeoecology and distribution of dinosaurs over time, complementing the skeletal (body) fossil record. These tracks are amongst the most popular and recognisable trace fossils in the natural world, attracting significant public interest and drawing visitors to sites in England, Scotland, and Wales. Beyond their scientific importance, they offer valuable aesthetic and educational opportunities in the tourism and education sectors. However, the protection, monitoring, communication, and scientific understanding of these sites vary widely. Here we review the nature of the fourteen <em>in-situ</em> dinosaur track sites present in the UK today, and subsequently use an established quantitative system to determine the relative scientific and cultural ‘value’ of each site. We find that the relative scientific and cultural value of UK track sites varies considerably, and that the two value types do not correlate with one another. UK sites with considerable national and international scientific value include the Late Triassic dinosaur track site Bendrick Rock, in South Wales, and the Middle Jurassic site Ardley Quarry, in Oxfordshire. By contrast, the Early Cretaceous dinosaur track sites at Hanover Point, Isle of Wight, and Spyway Quarry, Dorset have relatively high cultural value due to their accessibility and visitor appeal, but modest scientific value. This assessment helps identify threats and opportunities for UK dinosaur track sites, guiding future conservation, scientific research, and public engagement efforts.</div></div>","PeriodicalId":49672,"journal":{"name":"Proceedings of the Geologists Association","volume":"136 3","pages":"Article 101088"},"PeriodicalIF":1.2,"publicationDate":"2025-01-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143947740","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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 : 2025-01-09DOI: 10.1016/j.pgeola.2024.12.004
Samuel L.A. Cooper , Megan Jacobs , Lucrezia Ferrari , David M. Martill
An articulated and mostly complete skull roof of the enigmatic Early Jurassic chondrosteid fish, †Gyrosteus mirabilis Woodward ex Agassiz is described from the Whitby Mudstone Formation (Toarcian) of Whitby, Yorkshire. Known since the 1830s, isolated bones attributable to this taxon are frequently found along the Whitby coast, although articulated remains are rarely reported. The fragmentary nature of Gyrosteus mirabilis, the largest non-reptilian animal from the British Lower Jurassic, has led some researchers to propose it as a subjective synonym of †Chondrosteus Egerton ex Agassiz, from the Lower Lias of Dorset, and others to suggest synonymy with the similarly massive †Strongylosteus Jaekel from the Upper Lias (Toarcian) of Germany. Here, we compare the skull roof anatomies of †Gyrosteus mirabilis with †Chondrosteus acipenseroides and †Strongylosteus hindenburgi and present new criteria to differentiate between these taxa. We find the skull roofs of Chondrosteus and Strongylosteus to be vastly different with Gyrosteus representing something of an ‘intermediate’ morphology with closer affinities to Strongylosteus. The presence of a medial parietal and rostral bones is shared between Gyrosteus and Strongylosteus but these are absent in Chondrosteus. Our results support the taxonomic validity of both Gyrosteus mirabilis and Strongylosteus hindenburgi as monotypic genera distinct from Chondrosteus acipenseroides.
在约克郡惠特比的惠特比泥岩组（Toarcian）中，发现了一种神秘的早侏罗世软骨鱼，†Gyrosteus mirabilis Woodward ex Agassiz的关节状且基本完整的头骨顶。自19世纪30年代以来，人们就知道，在惠特比海岸经常发现属于这个分类群的孤立骨骼，尽管铰接的遗骸很少被报道。来自英国下侏罗纪的最大的非爬行类动物Gyrosteus mirabilis的碎片性使得一些研究人员认为它是来自多塞特（Dorset）下利亚斯（Toarcian）的†Chondrosteus Egerton ex Agassiz的主观同义词，而另一些人则认为它是来自德国上利亚斯（Toarcian）的同样巨大的†Strongylosteus Jaekel的同义词。本文比较了†Gyrosteus mirabilis与†Chondrosteus acpenserides和†Strongylosteus hindenburgi的头骨顶解剖结构，并提出了区分这些分类群的新标准。我们发现软骨龙和圆形龙的头骨顶部有很大的不同，圆形龙代表了一种与圆形龙更接近的“中间”形态。在Gyrosteus和Strongylosteus之间有共同的内侧顶骨和吻骨，但在Chondrosteus中没有。我们的研究结果支持了奇异Gyrosteus mirabilis和hindenburgi Strongylosteus作为单型属的有效性。
{"title":"Skull roof anatomy of the Early Jurassic (Toarcian) acipenseriform †Gyrosteus mirabilis Woodward ex Agassiz, from Yorkshire, England, elucidates diversity of †Chondrosteidae","authors":"Samuel L.A. Cooper , Megan Jacobs , Lucrezia Ferrari , David M. Martill","doi":"10.1016/j.pgeola.2024.12.004","DOIUrl":"10.1016/j.pgeola.2024.12.004","url":null,"abstract":"<div><div>An articulated and mostly complete skull roof of the enigmatic Early Jurassic chondrosteid fish, <sup>†</sup><em>Gyrosteus mirabilis</em> Woodward ex Agassiz is described from the Whitby Mudstone Formation (Toarcian) of Whitby, Yorkshire. Known since the 1830s, isolated bones attributable to this taxon are frequently found along the Whitby coast, although articulated remains are rarely reported. The fragmentary nature of <em>Gyrosteus mirabilis</em>, the largest non-reptilian animal from the British Lower Jurassic, has led some researchers to propose it as a subjective synonym of <sup>†</sup><em>Chondrosteus</em> Egerton ex Agassiz, from the Lower Lias of Dorset, and others to suggest synonymy with the similarly massive <sup>†</sup><em>Strongylosteus</em> Jaekel from the Upper Lias (Toarcian) of Germany. Here, we compare the skull roof anatomies of <sup>†</sup><em>Gyrosteus mirabilis</em> with <sup>†</sup><em>Chondrosteus acipenseroides</em> and <sup>†</sup><em>Strongylosteus hindenburgi</em> and present new criteria to differentiate between these taxa. We find the skull roofs of <em>Chondrosteus</em> and <em>Strongylosteus</em> to be vastly different with <em>Gyrosteus</em> representing something of an ‘intermediate’ morphology with closer affinities to <em>Strongylosteus</em>. The presence of a medial parietal and rostral bones is shared between <em>Gyrosteus</em> and <em>Strongylosteus</em> but these are absent in <em>Chondrosteus</em>. Our results support the taxonomic validity of both <em>Gyrosteus mirabilis</em> and <em>Strongylosteus hindenburgi</em> as monotypic genera distinct from <em>Chondrosteus acipenseroides</em>.</div></div>","PeriodicalId":49672,"journal":{"name":"Proceedings of the Geologists Association","volume":"136 3","pages":"Article 101089"},"PeriodicalIF":1.2,"publicationDate":"2025-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143947517","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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 : 2024-12-24DOI: 10.1016/j.pgeola.2024.12.002
Jonathan R. Lee , Sam Roberson
Repeated cycles of Quaternary glaciation have had a major impact on the morphology and shallow sub-surface properties of much of the UK landscape and continental shelf. Understanding the extent of glaciation involves understanding of our landscape history but is also critical to the broad range of applied users that interact with the shallow sub-surface including engineers, hydrogeologists, planners and decision makers. Numerous interpretations of the onshore extent of the Anglian and Late Devensian glaciations have been published. However, many are not clearly evidenced or justified, being sometimes based on anecdotal evidence or supposition, with the levels of associated uncertainty not effectively communicated. As part of this work, the long-term record of Quaternary glaciation within the UK is reviewed and the types of geological and geomorphological information that can be employed to interpret their former extent are assessed. We also examine the range of factors that may influence the relative preservation of this evidence. As part of this assessment, we recommend abandoning the term ‘glacial limit’ (and other related synonyms) when interpreting the extent of glaciation within the geological record. Instead, we recommend using the term limit of preserved evidence which more accurately reflects the spatial context of such evidence. Finally, we present new onshore linework for the limit of preserved evidence of both the Anglian and Late Devensian glaciations, presenting how this linework was captured and the associated levels of uncertainty.
{"title":"Refining the known extent of major onshore Quaternary glaciation in the UK — Types of evidence, nomenclature and uncertainty","authors":"Jonathan R. Lee , Sam Roberson","doi":"10.1016/j.pgeola.2024.12.002","DOIUrl":"10.1016/j.pgeola.2024.12.002","url":null,"abstract":"<div><div>Repeated cycles of Quaternary glaciation have had a major impact on the morphology and shallow sub-surface properties of much of the UK landscape and continental shelf. Understanding the extent of glaciation involves understanding of our landscape history but is also critical to the broad range of applied users that interact with the shallow sub-surface including engineers, hydrogeologists, planners and decision makers. Numerous interpretations of the onshore extent of the Anglian and Late Devensian glaciations have been published. However, many are not clearly evidenced or justified, being sometimes based on anecdotal evidence or supposition, with the levels of associated uncertainty not effectively communicated. As part of this work, the long-term record of Quaternary glaciation within the UK is reviewed and the types of geological and geomorphological information that can be employed to interpret their former extent are assessed. We also examine the range of factors that may influence the relative preservation of this evidence. As part of this assessment, we recommend abandoning the term ‘glacial limit’ (and other related synonyms) when interpreting the extent of glaciation within the geological record. Instead, we recommend using the term <em>limit of preserved evidence</em> which more accurately reflects the spatial context of such evidence. Finally, we present new onshore linework for the limit of preserved evidence of both the Anglian and Late Devensian glaciations, presenting how this linework was captured and the associated levels of uncertainty.</div></div>","PeriodicalId":49672,"journal":{"name":"Proceedings of the Geologists Association","volume":"136 3","pages":"Article 101087"},"PeriodicalIF":1.2,"publicationDate":"2024-12-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143947739","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Typical liquefaction-induced soft-sediment deformation structures were recognised in the Neogene-age tide-dominated estuarine sedimentary succession Bled El Trayfa in the Tafna basin (NW Algeria). Although NW Algeria was tectonically active during late Neogene, we suggest that another trigger mechanism that is not related to earthquakes is responsible for the liquefaction phenomenon and the development of soft-sediment deformation structures in the area. The sedimentary succession called the Bled El Trayfa exhibits tidal rhythmites, heterolithic beddings, bi-directional cross-laminae, and tidal bore couplets deposited in tidal flats within the intertidal environment. A tidal bore, defined as upstream-propagating hydraulic jumps associated with the flood tide in estuarine rivers, is proposed as the main trigger mechanism responsible for the liquefaction phenomenon and the development of soft-sediment deformation structures. This suggestion was made on a set of observed arguments: firstly, the presence of draping massive sand underlain by erosional surfaces indicating scouring by upstream-propagating bores, followed by a very rapid deposition in a tide-dominated estuarine from the intertidal environment and secondly, the formation of distinctive (typical) soft-sediment deformation structures, characterised by convoluted and folded structure like flow rolls along with associated dewatering structures. Alongside flow rolls as typical and dominant soft-sediment deformation structures, the succession also includes load casts, recumbent folds, water-escape structures, convolute laminations, ball-and-pillow structures, and flame structures. Even though the relationship between the tidal bore and sediment deformation structures has been proved in some current researches, the Bled El Trayfa succession was considered among the rare areas where this relationship was identified as the origin of SSDSs in ancient rock record.
在阿尔及利亚西北部塔夫纳盆地新近系以潮汐为主导的河口沉积序列Bled El Trayfa中发现了典型的液化软沉积变形构造。尽管阿尔及利亚西北部晚新近纪构造活动活跃，但我们认为该地区的液化现象和软沉积变形构造的发育有另一种与地震无关的触发机制。该沉积序列显示潮间带环境中潮滩上的潮节律岩、异质层理、双向交叉纹层和潮孔对联沉积。潮涌是指河口河流中与涨潮相关的上游传播的水力跳跃，它是液化现象和软沉积变形结构形成的主要触发机制。这一建议是基于一系列观察到的论点提出的：首先，在侵蚀表面下存在着大量的覆盖砂，表明上游传播钻孔的冲刷，其次是潮间带环境中潮汐主导的河口的快速沉积，其次，形成了独特的（典型的）软沉积变形结构，其特征是像流卷一样的卷曲和折叠结构以及相关的脱水结构。除了以流卷为典型和主导的软沉积变形构造外，还包括荷载浇筑、平卧褶皱、泄水构造、卷曲层状构造、球枕构造和火焰构造。尽管目前已有一些研究证实了潮涌与沉积物变形构造之间的关系，但在古岩石记录中，这种关系被确定为ssds起源的罕见地区被认为是Bled El Trayfa演替。
{"title":"Soft-sediment deformation structures of tide origin: A case study from the late Miocene Tafna Basin (NW Algeria)","authors":"Mostapha Benzina , Abdelmalik Draoui , Hakim Hebib , Małgorzata Pisarska-Jamroży","doi":"10.1016/j.pgeola.2024.12.001","DOIUrl":"10.1016/j.pgeola.2024.12.001","url":null,"abstract":"<div><div>Typical liquefaction-induced soft-sediment deformation structures were recognised in the Neogene-age tide-dominated estuarine sedimentary succession Bled El Trayfa in the Tafna basin (NW Algeria). Although NW Algeria was tectonically active during late Neogene, we suggest that another trigger mechanism that is not related to earthquakes is responsible for the liquefaction phenomenon and the development of soft-sediment deformation structures in the area. The sedimentary succession called the Bled El Trayfa exhibits tidal rhythmites, heterolithic beddings, bi-directional cross-laminae, and tidal bore couplets deposited in tidal flats within the intertidal environment. A tidal bore, defined as upstream-propagating hydraulic jumps associated with the flood tide in estuarine rivers, is proposed as the main trigger mechanism responsible for the liquefaction phenomenon and the development of soft-sediment deformation structures. This suggestion was made on a set of observed arguments: firstly, the presence of draping massive sand underlain by erosional surfaces indicating scouring by upstream-propagating bores, followed by a very rapid deposition in a tide-dominated estuarine from the intertidal environment and secondly, the formation of distinctive (typical) soft-sediment deformation structures, characterised by convoluted and folded structure like flow rolls along with associated dewatering structures. Alongside flow rolls as typical and dominant soft-sediment deformation structures, the succession also includes load casts, recumbent folds, water-escape structures, convolute laminations, ball-and-pillow structures, and flame structures. Even though the relationship between the tidal bore and sediment deformation structures has been proved in some current researches, the Bled El Trayfa succession was considered among the rare areas where this relationship was identified as the origin of SSDSs in ancient rock record.</div></div>","PeriodicalId":49672,"journal":{"name":"Proceedings of the Geologists Association","volume":"136 3","pages":"Article 101086"},"PeriodicalIF":1.2,"publicationDate":"2024-12-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143947738","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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 : 2024-12-01DOI: 10.1016/j.pgeola.2024.11.001
Jon W. Merritt , Nicholas T. Smith , Emrys Phillips , Clive A. Auton
The glacial evolution of western Cumbria, England is reassessed following a comprehensive review of both published and extensive unpublished records from the Sellafield area, together with targeted fieldwork. The exercise scrutinises evidence for glacial readvances across former ice-dammed lakes, determining their occurrence, relative age, extent and legacy. It is concluded that the area was affected by at least two substantial glacial readvances following the maximum build-up of ice during the last, Late Devensian (Weichselian/Wisconsin) glaciation. The earlier Gosforth Oscillation involved locally sourced ice together with ice that circulated around the north of the Lake District into the Irish Sea basin whilst most of the region was substantially glaciated. The subsequent Fishgarth Wood Readvance involved ice flowing from the north, but when an ice centre positioned over the western Southern Uplands of Scotland had become dominant. Glacial oscillations across the coastal plain have resulted in a complex interdigitating sequence of sediments of contrasting permeability and physical properties, commonly preserved within buried valleys. The genesis of some thin units of clay-rich diamicton and pebbly clay previously interpreted as till is discussed in the light of ongoing debate concerning their possible glaciolacustrine origin.
{"title":"A detailed investigation into the legacy of glacial readvances and ice-dammed lakes around Sellafield, West Cumbria: Implications for 3D modelling, hydrogeology and ground engineering","authors":"Jon W. Merritt , Nicholas T. Smith , Emrys Phillips , Clive A. Auton","doi":"10.1016/j.pgeola.2024.11.001","DOIUrl":"10.1016/j.pgeola.2024.11.001","url":null,"abstract":"<div><div>The glacial evolution of western Cumbria, England is reassessed following a comprehensive review of both published and extensive unpublished records from the Sellafield area, together with targeted fieldwork. The exercise scrutinises evidence for glacial readvances across former ice-dammed lakes, determining their occurrence, relative age, extent and legacy. It is concluded that the area was affected by at least two substantial glacial readvances following the maximum build-up of ice during the last, Late Devensian (Weichselian/Wisconsin) glaciation. The earlier Gosforth Oscillation involved locally sourced ice together with ice that circulated around the north of the Lake District into the Irish Sea basin whilst most of the region was substantially glaciated. The subsequent Fishgarth Wood Readvance involved ice flowing from the north, but when an ice centre positioned over the western Southern Uplands of Scotland had become dominant. Glacial oscillations across the coastal plain have resulted in a complex interdigitating sequence of sediments of contrasting permeability and physical properties, commonly preserved within buried valleys. The genesis of some thin units of clay-rich diamicton and pebbly clay previously interpreted as till is discussed in the light of ongoing debate concerning their possible glaciolacustrine origin.</div></div>","PeriodicalId":49672,"journal":{"name":"Proceedings of the Geologists Association","volume":"135 6","pages":"Pages 695-743"},"PeriodicalIF":1.2,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143151420","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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 : 2024-12-01DOI: 10.1016/j.pgeola.2024.07.001
Andy S. Gale , John W.M. Jagt
A new species of the “living fossil” crinoid Cyathidium, C. phosphaticola, is described from lower Campanian phosphatic chalks in southern England and northern France. The squat, robust stalkless crinoid lived in high-energy conditions in phosphate chalk basins, attached to the surface of the basal hardground. Other Cretaceous and lower Paleogene occurrences of the genus, from France, the Czech Republic and Denmark are briefly reviewed.
{"title":"The aberrant crinoid Cyathidium (Echinodermata, Crinoidea, Cyrtocrinida) from lower Campanian phosphatic chalk in West Sussex (UK) and Picardie (France)","authors":"Andy S. Gale , John W.M. Jagt","doi":"10.1016/j.pgeola.2024.07.001","DOIUrl":"10.1016/j.pgeola.2024.07.001","url":null,"abstract":"<div><div>A new species of the “living fossil” crinoid <em>Cyathidium</em>, <em>C. phosphaticola</em>, is described from lower Campanian phosphatic chalks in southern England and northern France. The squat, robust stalkless crinoid lived in high-energy conditions in phosphate chalk basins, attached to the surface of the basal hardground. Other Cretaceous and lower Paleogene occurrences of the genus, from France, the Czech Republic and Denmark are briefly reviewed.</div></div>","PeriodicalId":49672,"journal":{"name":"Proceedings of the Geologists Association","volume":"135 6","pages":"Pages 631-638"},"PeriodicalIF":1.2,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142199411","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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 : 2024-12-01DOI: 10.1016/j.pgeola.2024.10.001
Andrew S. Gale , David J. Ward
A new genus and species of starfish in the family Solasteridae, Lacosteaster lauerorum gen. et sp. nov., are described from the mid-Miocene of Lacoste, south-east France. The genus differs from all known extant solasterids and the only other fossil (Middle Jurassic) representative of the family in the presence of single, large conical spines on ossicles of the undersurface, and large bladed spines surrounding the mouth.
记述了法国东南部Lacoste中新世中期海星科一新属和新种，lacostaster lauerorum gen. et sp. nov.。该属不同于所有已知的现存太阳小行星和该科的唯一代表化石（中侏罗世），在其下表面的小骨上有单个的大圆锥形刺，在嘴周围有大的叶片状刺。
{"title":"A new sun star (Echinodermata, Asteroidea, Solasteridae) from the mid-Miocene of Lacoste, France","authors":"Andrew S. Gale , David J. Ward","doi":"10.1016/j.pgeola.2024.10.001","DOIUrl":"10.1016/j.pgeola.2024.10.001","url":null,"abstract":"<div><div>A new genus and species of starfish in the family Solasteridae, <em>Lacosteaster lauerorum</em> gen. et sp. nov., are described from the mid-Miocene of Lacoste, south-east France. The genus differs from all known extant solasterids and the only other fossil (Middle Jurassic) representative of the family in the presence of single, large conical spines on ossicles of the undersurface, and large bladed spines surrounding the mouth.</div></div>","PeriodicalId":49672,"journal":{"name":"Proceedings of the Geologists Association","volume":"135 6","pages":"Pages 685-694"},"PeriodicalIF":1.2,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143151423","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-12-01DOI: 10.1016/j.pgeola.2024.09.003
Darren Withers , David M. Martill , Roy E. Smith , Michael Ashton , Anusuya Chinsamy , Charles Wood , Richard Forrest
An incomplete, but large hollow bone is identified as pterosaurian on account of its pneumatic nature, thin bone wall, palaeohistology and the characteristic surface texture of the peridermal bone. Despite being incomplete it is tentatively identified as a ?left ulna, and is remarkable for its size. Coming from the lower Middle Jurassic Lincolnshire Limestone Formation of Rutland, eastern England, this is the first record anywhere in the World of a Bajocian pterosaur, and probably the first pterosaur recorded from Rutland. It is most likely from Discites to Laeviuscula zones part of the lower Bajocian succession, and represents one of the largest Jurassic pterosaurs yet recorded, with a wingspan tentatively estimated at between 3.5 and 4.0 m. The taxonomic identity of the new specimen is uncertain, but it is likely allied to the Pterodactyloidea on account of its size, although presently it remains Pterosauria fam. et gen., et sp. indet.
由于其气动性质、薄骨壁、古组织学和表皮骨的特征表面纹理，一个不完整但大的空心骨被确定为翼龙骨。尽管它是不完整的，但它暂时被确定为左尺骨，并且它的大小非常引人注目。来自英格兰东部拉特兰郡中侏罗世林肯郡石灰岩地层，这是世界上第一个记录到的巴约西亚翼龙，也可能是拉特兰郡记录到的第一个翼龙。它很可能来自discite到Laeviuscula地带，是巴约西亚下部演替的一部分，是迄今为止有记录的最大的侏罗纪翼龙之一，翼展初步估计在3.5到4.0 米之间。新标本的分类身份尚不确定，但由于其大小，它可能属于翼手亚科，尽管目前它仍然是翼龙家族。Et gen., Et sp.；
{"title":"A large pterosaur from the Middle Jurassic (lower Bajocian) of Rutland, United Kingdom","authors":"Darren Withers , David M. Martill , Roy E. Smith , Michael Ashton , Anusuya Chinsamy , Charles Wood , Richard Forrest","doi":"10.1016/j.pgeola.2024.09.003","DOIUrl":"10.1016/j.pgeola.2024.09.003","url":null,"abstract":"<div><div>An incomplete, but large hollow bone is identified as pterosaurian on account of its pneumatic nature, thin bone wall, palaeohistology and the characteristic surface texture of the peridermal bone. Despite being incomplete it is tentatively identified as a ?left ulna, and is remarkable for its size. Coming from the lower Middle Jurassic Lincolnshire Limestone Formation of Rutland, eastern England, this is the first record anywhere in the World of a Bajocian pterosaur, and probably the first pterosaur recorded from Rutland. It is most likely from Discites to Laeviuscula zones part of the lower Bajocian succession, and represents one of the largest Jurassic pterosaurs yet recorded, with a wingspan tentatively estimated at between 3.5 and 4.0 m. The taxonomic identity of the new specimen is uncertain, but it is likely allied to the Pterodactyloidea on account of its size, although presently it remains Pterosauria fam. et gen., et sp. indet.</div></div>","PeriodicalId":49672,"journal":{"name":"Proceedings of the Geologists Association","volume":"135 6","pages":"Pages 660-675"},"PeriodicalIF":1.2,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143151421","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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