Proceedings of the Geologists Association最新文献

{"title":"New information on the Dyrham Formation (Lower Jurassic, Pliensbachian) of the East Midlands Shelf, UK","authors":"Robin I. Knight","doi":"10.1016/j.pgeola.2024.08.004","DOIUrl":"10.1016/j.pgeola.2024.08.004","url":null,"abstract":"<div><div>Previously unpublished Lower Jurassic sections of the East Midlands Shelf, along with reassessment of museum collections and previously published successions, indicate that seafloor sedimentation was dominated by complex erosional and depositional processes driven by dynamic and complex shelfal seafloor energy regimes during the Davoei and Margaritatus Zones of the Pliensbachian. The possible influence of tectonically driven relative sea level fluctuations is uncertain. Distinct condensation events, marked by authigenic mineralisation and clast reworking, can be identified at the Davoei–Margaritatus zonal boundary at the base of the Stokesi Subzone (‘Lower Authigenic Mineral Bed’), and at the boundary between the Stokesi and Subnodosus Subzones (‘Upper Authigenic Mineral Bed’). These correspond to a recognised candidate sequence boundary and candidate maximum flooding surface respectively. The Stokesi Subzone is well defined in all the studied sections by the ammonites between the two marker beds, whilst the Subnodosus Subzone can only be proven at Middleton Cheney. Nutrient supply for mineralisation observed in the ‘Authigenic Mineral Beds’ was derived from the erosion of uppermost Davoei Zone and lowermost Stokesi Subzone sediments. The high concentrations of authigenic mineralisation ions in the Davoei sediments were generated by large amounts of organic material derived from continental run-off.</div></div>","PeriodicalId":49672,"journal":{"name":"Proceedings of the Geologists Association","volume":"135 5","pages":"Pages 545-568"},"PeriodicalIF":1.2,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142540226","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}

{"title":"A new Early Cretaceous ommatine beetle (Insecta: Coleoptera: Archostemata) from Inner Mongolia, China","authors":"Yingshun Tang ,&nbsp;Ming Li ,&nbsp;Zhengyu Song ,&nbsp;Honghe Xu ,&nbsp;Hui Wang ,&nbsp;Edmund A. Jarzembowski ,&nbsp;Bo Wang","doi":"10.1016/j.pgeola.2024.08.002","DOIUrl":"10.1016/j.pgeola.2024.08.002","url":null,"abstract":"<div><div>A new archostematan beetle, <em>Brochocoleus sonidensis</em> sp. nov. (Insecta: Coleoptera: Archostemata) is described based on a specimen preserved in the dorsal aspect from the Lower Cretaceous Damoguaihe Formation of Inner Mongolia, China. The new species is the first body species of the genus disinterred in China and can be distinguished from the other congeners based on its largest known size, not strong forward convergence of the lateral edges of the prothorax, and the unique combination of the aspect ratios of the pronotum and head.</div></div>","PeriodicalId":49672,"journal":{"name":"Proceedings of the Geologists Association","volume":"135 5","pages":"Pages 528-532"},"PeriodicalIF":1.2,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142540228","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}

{"title":"Stratigraphy and sedimentology of the upper Cenomanian–lower Coniacian in the Northern Aures Range (Algeria)","authors":"","doi":"10.1016/j.pgeola.2024.03.003","DOIUrl":"10.1016/j.pgeola.2024.03.003","url":null,"abstract":"<div><div><span><span>The stratigraphical features and palaeoenvironmental conditions of the upper Cenomanian–lower Coniacian carbonates from the northern part of the Aures Range are described for the first time. Four formations have been recognised, namely the Arris, Adahri, Yabous, and Bou Ouali, respectively. Planktonic foraminifera enable us to assign the upper part of the Arris Formation and the lower part of the Adahri Formation to the Middle–Upper </span>Cenomanian (</span><em>Rotalipora</em> sp. cf. <em>R. cushmani</em><span> Total Range Zone), the upper part of the Adahri Formation to the Cenomanian–Turonian Transition to the lower Turonian (</span><em>Whiteinella archaeocretacea</em> Partial Range Zone and <em>Helvetoglobotruncana helvetica</em> Total-Range Zone, respectively), the lower member of the Yabous Formation to the middle Turonian (<em>Marginotruncana sigali</em> Partial Range Zone), and the upper member of the Yabous Formation to the upper Turonian (<em>Marginotruncana schneegansi</em><span><span><span> Partial Range Zone). The Turonian–Coniancian boundary was dated approximately. This biozonation<span> enables a correlation with several upper Cenomanian–lower Coniacian sections outside Algeria, mainly within the Tethyan and Boreal domains. Based on the field data, and microfacies studies, the strata of these formations are arranged into eleven microfacies types (MT 1 to MT 11) that are described in terms of </span></span>depositional environments, and grouped into three main facies associations (FA 1, FA 2, and FA 3): (i) a deep shelf-basin facies zone; (ii) marginal sand shoals, an open-marine/restricted platform facies zone; and (iii) an outer platform and toe-of-slope/distal slope facies zone. Analysis of the </span>sequence stratigraphy<span> has allowed the recognition of three third-order depositional sequences grouped into two megasequences and correlated to a regional scale.</span></span></div></div>","PeriodicalId":49672,"journal":{"name":"Proceedings of the Geologists Association","volume":"135 5","pages":"Pages 613-630"},"PeriodicalIF":1.2,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140282963","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}

{"title":"Lateglacial Interstadial to mid-Holocene stratigraphy and palynology at Pepper Arden Bottoms, North Yorkshire, UK","authors":"James B. Innes ,&nbsp;Mairead M. Rutherford ,&nbsp;David R. Bridgland ,&nbsp;Ben R. Gearey ,&nbsp;Malcolm C. Lillie ,&nbsp;Wishart A. Mitchell ,&nbsp;Charlotte E. O'Brien ,&nbsp;Richard T. Jones ,&nbsp;Gareth J. Thompson","doi":"10.1016/j.pgeola.2024.08.005","DOIUrl":"10.1016/j.pgeola.2024.08.005","url":null,"abstract":"<div><div>Investigations at Pepper Arden Bottoms, a lake basin site on the interfluve between the rivers Tees and Swale in northeast England, have recovered lithostratigraphical, pollen and plant macrofossil sequences which have allowed the reconstruction of sedimentary and vegetation history from the Lateglacial Interstadial to the post-<em>Ulmus</em> Decline mid-Holocene. Although the calcareous nature of the sediment and lack of terrestrial plant macrofossils precluded radiocarbon dating of sediments pre-dating the <em>Ulmus</em> Decline, pollen analyses showed sediment accumulation from the middle of the Lateglacial Interstadial, with the lake catchment remaining poorly vegetated until the Holocene, with low values for woody taxa, and grasses and sedges dominant. The late Interstadial cold phase GI-1b is present in the pollen stratigraphy, with a major reduction in <em>Betula</em> frequencies, replaced by <em>Juniperus</em>, and an increase in cold-tolerant herbs, mainly grasses and sedges. Microcharcoal frequencies are consistently substantial throughout the Lateglacial levels, probably indicating a natural fire regime, but are absent from the Holocene, suggesting little Mesolithic or Neolithic activity nearby, which is confirmed by a lack of pollen indicators of disturbance. The Lateglacial (Loch Lomond) Stadial is entirely dominated by Cyperaceae and Poaceae pollen, with very few trees and shrubs. The successive migration of postglacial thermophilous trees is recorded in the Holocene and possible effects of the Preboreal Oscillation and the 8.2 ka BP cold events are recognised. An <em>Ulmus</em> Decline occurs near the top of the profile, after which the assemblage is dominated by <em>Alnus</em> as the lake became terrestrialised and was occupied by fen and then alder carr. The very open Lateglacial vegetation adds this site to a northern group in northeast England with poor Lateglacial woodland development, in contrast to sites to the south, in North Yorkshire, where Lateglacial <em>Betula</em> woodland was much better established.</div></div>","PeriodicalId":49672,"journal":{"name":"Proceedings of the Geologists Association","volume":"135 5","pages":"Pages 569-588"},"PeriodicalIF":1.2,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142540225","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}

{"title":"The structural setting and geometry of the Faringdon Trough defined by subsurface mapping","authors":"Nigel Banks","doi":"10.1016/j.pgeola.2024.09.001","DOIUrl":"10.1016/j.pgeola.2024.09.001","url":null,"abstract":"<div><div>Data from over 80 boreholes have been used together with the surface geology to interpret the subsurface structure and stratigraphy of the Corallian to Gault (Upper Jurassic to Lower Cretaceous) sediments in the Vale of the White Horse, between Faringdon and Wantage in West Oxfordshire. The gentle regional dip to the SSE of the sediments in this area is interrupted by two major features. The first is the Faringdon Fault, first defined at outcrop just east of Faringdon. This has been traced SE from the outcrop extent for at least 8 km in the subsurface towards Wantage. It has an estimated maximum downthrow to the SW of <em>ca</em> 40 m. Contrary to previous interpretations, this fault was probably active during Kimmeridge Clay deposition.</div><div>The second feature is the Faringdon Trough, an erosional palaeovalley filled with at least 50 m of marine Lower Greensand sediments. The Trough trends SSE from Faringdon and cuts deeply through the Kimmeridge Clay to reach the underlying Corallian. A subtle structural feature, here named the Baulking Fault, has a throw of &lt;<!--> <!-->10 m and its movement was probably pre-Cretaceous, but it seems to have influenced the path and geometry of the Faringdon Trough, dividing it into two segments. Contrary to previous interpretations, subsurface mapping suggests that the main Trough has a broad U-shape in cross-section with a planar base where it rests on resistive Corallian limestone. Along its margins depositional dips of up to 9° have been widely recorded in the Lower Greensand sediments.</div></div>","PeriodicalId":49672,"journal":{"name":"Proceedings of the Geologists Association","volume":"135 5","pages":"Pages 596-612"},"PeriodicalIF":1.2,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142540326","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}

{"title":"Early Miocene lacustrine deposits from the Oued Tilatou Formation (Aurès Massif, Eastern Algeria): Sedimentology, micropalaeontology, and palaeoenvironmental implications","authors":"Somia Khanfer ,&nbsp;Fouad Djaiz ,&nbsp;Josep Sanjuan ,&nbsp;Lucas Silveira Antonietto ,&nbsp;Bachir Lamouri ,&nbsp;Amine Cherif ,&nbsp;Hicham El Asmi ,&nbsp;Cameron Manche","doi":"10.1016/j.pgeola.2024.08.003","DOIUrl":"10.1016/j.pgeola.2024.08.003","url":null,"abstract":"<div><div>Lacustrine depositional systems provide a valuable record of palaeoenvironmental conditions since they rely on a delicate balance between accommodation space and water-sediment supply controlled by tectonic activity and climatic conditions. This study presents new sedimentological and micropalaeontological information from the early Miocene lacustrine Oued Tilatou Formation, northeastern Algeria. Based on sedimentary facies and microfossil assemblages, the Oued Tilatou Formation (OTF) is divided into two discrete units, the Lower OTF and the Upper OTF. The Lower OTF is characterised by reddish clay-rich carbonate mudstone containing reworked foraminifera and ostracods interspersed by polymodal clast-supported conglomerates attributed to alluvial deposition. The Lower OTF was deposited under fluvial–palustrine conditions, marked by a notable terrigenous sediment influx. In contrast, the Upper OTF encompasses greenish charophyte-dominated (<em>Sphaerochara</em> sp.) carbonate mudstone interbedded with silty carbonate mudstone, and dolomitic wackestone containing charophyte thalli, several ostracod species, and stromatolites. The dominant ostracod taxa within this interval are <em>Mediocypris</em> sp. cf. <em>M. candonaeformis</em>, indicating freshwater–brackish water conditions. The transition in depositional facies from the Lower OTF to the Upper OTF is interpreted as reflecting changes in the environment from fluvial–palustrine to shallow water lacustrine with fluctuation in freshwater input during the Burdigalian (Early Miocene). This study provides new insights on the interplay between early Miocene climate conditions and the tectonic uplift of the Aurès Massif, and their implications for lacustrine palaeoenvironmental conditions.</div></div>","PeriodicalId":49672,"journal":{"name":"Proceedings of the Geologists Association","volume":"135 5","pages":"Pages 533-544"},"PeriodicalIF":1.2,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142540227","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}

{"title":"A Tithonian (Upper Jurassic) lake shoreline in Buckinghamshire, UK: Evidence from stromatolite distribution in the Purbeck Formation","authors":"Jonathan D. Radley ,&nbsp;Robert A. Coram","doi":"10.1016/j.pgeola.2024.08.001","DOIUrl":"10.1016/j.pgeola.2024.08.001","url":null,"abstract":"<div><div>Stromatolites in the essentially non-marine Purbeck Formation (Tithonian, Upper Jurassic) west of Aylesbury (Buckinghamshire, UK) cap an erosion surface truncating lacustrine–palustrine carbonates, previously documented from an exposure close to the site of the former Bugle Pit, Hartwell. The stromatolite occurrences in this area follow a regional northwest–southeast structural grain, evidenced by local normal faults, some demonstrably active during Late Jurassic–Early Cretaceous time. Observations from associated lithofacies and biota suggest a littoral lacustrine setting for the stromatolite ‘belt’. We hypothesise that the present-day stromatolite distribution reflects a fault-controlled palaeo-shoreline, and that growth of the stromatolites was linked to lacustrine transgression driven by syn-sedimentary movement on these faults. Littoral sand associated with the stromatolites was possibly reworked from older marine sediments undergoing erosion on a nearby fault footwall, or distally, on the western margin of the Anglo-Brabant Massif.</div></div>","PeriodicalId":49672,"journal":{"name":"Proceedings of the Geologists Association","volume":"135 5","pages":"Pages 518-527"},"PeriodicalIF":1.2,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142540229","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}

{"title":"Microvertebrates from the Lower Greensand Group (Lower Cretaceous) of Clophill, Bedfordshire, UK, and Nutfield, Surrey, UK","authors":"Lila Blake ,&nbsp;Max Fursman ,&nbsp;Christopher J. Duffin ,&nbsp;Trevor Batchelor ,&nbsp;Claudia Hildebrandt ,&nbsp;Michael J. Benton","doi":"10.1016/j.pgeola.2024.07.002","DOIUrl":"10.1016/j.pgeola.2024.07.002","url":null,"abstract":"<div><div>The Lower Greensand of southern England (early Aptian–early Albian; <em>c.</em>, 120–110 Ma) has yielded diverse faunas of vertebrates, but these have not been reported in detail. Here, we present rich faunas, mainly comprising sharks, bony fishes, and crocodyliforms, from two localities to the north and south of the London–Brabant Massif. The first, Clophill Quarry, near Leighton Buzzard in Bedfordshire, has yielded fossils from the Brown Sands Formation, representing an inshore, tidally influenced environment, such as an estuary mouth. The second, Patteson Court Quarry, Nutfield, Surrey, has produced fossils from the Sandgate Formation (Redhill Sands Member). The faunas of both locations are similar, and they share a remarkable assemblage of at least 23 chondrichthyan taxa, one <em>Edaphodon</em>-like chimaeroid, ten hybodontiform sharks, and 12 neoselachian sharks. The hybodontiform sharks comprise two morphological groups, those with high-cusped piercing teeth, sometimes with lateral cusplets and a coronal ornament of vertical ridges, and those with low-crowned crushing teeth. The 12 species of neoselachian sharks include one representative of the extinct Synechodontiformes, as well as examples of the modern orders Hexanchiformes, Lamniformes, Carchariniformes, Squatiniformes, Heterodontiformes, and Orectolobiformes. Bony fishes are represented mostly by crushing teeth of Pycnodontiformes, Aspidorhynchiformes, Amiiformes, Lepisosteiformes, and Semionotiformes. Crocodyliforms are identified from seven morphotypes of elongate, goniopholid-like teeth. Based on these fossil teeth, the fauna is 53 % chondrichthyan and 21 % osteichthyan; neoselachians represent 32–45 % of the chondrichthyans, lower than figures from the underlying Wealden.</div></div>","PeriodicalId":49672,"journal":{"name":"Proceedings of the Geologists Association","volume":"135 5","pages":"Pages 493-517"},"PeriodicalIF":1.2,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142540286","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}

{"title":"Re-assessing the age of the type locality of Nythosaurus larvatus (Therapsida, Cynodontia) and implications on the evolutionary dynamics of cynodonts","authors":"J. Benoit,&nbsp;S. Jirah,&nbsp;E.S. Lund,&nbsp;T. Lafferty,&nbsp;V. Buffa,&nbsp;L.A. Norton","doi":"10.1016/j.pgeola.2024.08.007","DOIUrl":"10.1016/j.pgeola.2024.08.007","url":null,"abstract":"<div><div><em>Nythosaurus larvatus</em> was one of the first cynodonts named and, for a long time, the only therapsid for which the endocranial cast was described. The holotype and only skull of this species is thus a landmark in the history of therapsid palaeontology. It is believed to have come from Commissie Drift 303 (Free State Province, South Africa), a locality that has been traditionally dated to the <em>Lystrosaurus declivis</em> Assemblage Zone. However, this age was mostly based on the synonymy between <em>Nythosaurus larvatus</em> and <em>Thrinaxodon liorhinus</em>, the former being the only fossil indisputably reported from this locality and the latter being an index taxon for the <em>Lystrosaurus declivis</em> Assemblage Zone. A recent revision of <em>Nythosaurus larvatus</em> also questioned the age of Commissie Drift. Here, we report the result of our fieldwork to re-assess the age of this locality. We find that the stratigraphy conforms to the lower Burgersdorp Formation and that the fossil tetrapod fauna does not match the <em>Lystrosaurus declivis</em> Assemblage Zone. The overall scarcity of fossil bones, absence of plants and dicynodonts, and relative dominance of amphibian remains all point to an assignation to the <em>Langbergia</em>–<em>Garjainia</em> Subzone of the <em>Cynognathus</em> Assemblage Zone, which is consistent with the stratigraphy. The discovery of new material attributable to cf. <em>Nythosaurus</em> bolsters the notion that this taxon is from the late Olenekian. <em>Nythosaurus larvatus</em> can safely be considered a valid taxon, and may in fact occur elsewhere in this subzone.</div></div>","PeriodicalId":49672,"journal":{"name":"Proceedings of the Geologists Association","volume":"135 5","pages":"Pages 589-595"},"PeriodicalIF":1.2,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142540287","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}

{"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":"https://doi.org/10.1016/j.pgeola.2024.07.001","url":null,"abstract":"A new species of the “living fossil” crinoid , , 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.","PeriodicalId":49672,"journal":{"name":"Proceedings of the Geologists Association","volume":"405 1","pages":""},"PeriodicalIF":1.2,"publicationDate":"2024-08-02","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}