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evolution of western Cumbria, England is reassessed following a comprehensive review of both published and extensive unpublished records from the Sellafield area, together with targeted fieldwork.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evolution of western Cumbria, England is reassessed following a comprehensive review of both published and extensive unpublished records from the Sellafield area, together with targeted fieldwork.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.
{"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.
{"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}
Pub Date : 2024-12-01DOI: 10.1016/j.pgeola.2024.09.004
David M. Martill , Danielle Milbank , Mike Romano , Roy E. Smith
An enigmatic partial trackway from the Aalenian to Bathonian (Middle Jurassic) Ravenscar Group of Whitby, North Yorkshire bears a striking resemblance to the pterosaur trace Pteraichinus. It also displays some similarities with the xiphosuran trackway Kouphichnium. The trackway is assigned to a new ichnogenus and ichnospecies Pseudopteraichnus whitbyensis. Using tetrapods as a comparator, Pseudopteraichnus is characterised by an elongate ‘heel’, a sub-triangular ‘tarsus’ and four unequal ‘digits’. A possible fifth digit is located posterolaterally. The track maker is unknown.
{"title":"Enigmatic trace fossil from the Middle Jurassic Ravenscar Group of Yorkshire, England","authors":"David M. Martill , Danielle Milbank , Mike Romano , Roy E. Smith","doi":"10.1016/j.pgeola.2024.09.004","DOIUrl":"10.1016/j.pgeola.2024.09.004","url":null,"abstract":"<div><div>An enigmatic partial trackway from the Aalenian to Bathonian (Middle Jurassic) Ravenscar Group of Whitby, North Yorkshire bears a striking resemblance to the pterosaur trace <em>Pteraichinus</em>. It also displays some similarities with the xiphosuran trackway <em>Kouphichnium</em>. The trackway is assigned to a new ichnogenus and ichnospecies <em>Pseudopteraichnus whitbyensis</em>. Using tetrapods as a comparator, <em>Pseudopteraichnus</em> is characterised by an elongate ‘heel’, a sub-triangular ‘tarsus’ and four unequal ‘digits’. A possible fifth digit is located posterolaterally. The track maker is unknown.</div></div>","PeriodicalId":49672,"journal":{"name":"Proceedings of the Geologists Association","volume":"135 6","pages":"Pages 676-684"},"PeriodicalIF":1.2,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143151422","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.2024.09.002
Dariusz Krzyszkowski , Lucyna Wachecka-Kotkowska , Marcin Krawczyk , David Bridgland
This article addresses the development of Pleistocene terraces in the Bystrzyca River catchment (Sudetic Foreland, Southwestern Poland) in the vicinity of the Sudetic Marginal Fault, within the Roztoka–Mokrzeszów Graben. Nineteen research sites located within the Świdnica Plain are documented in this paper, representative of terraces of the Bystrzyca and its Piława and Witoszówka tributaries, with reporting on analyses of structure, grain size, petrography, quartz-grain morphoscopy, and heavy minerals. The Bystrzyca River, flowing in the largest and deepest valley in the Sowie Mountains, crossing the fault zone and extending into the Sudetic Foreland, has been influenced by significant tectonic and glacial events. During the Middle Pleistocene a fluvial piedmont fan was formed and survives as traces of higher-level (pre-Saalian) terraces. The main fluvial terraces are recognized as follows: an Upper Terrace, from the Saalian, a Middle Terrace from the Upper Pleistocene Last Glacial (Weichselian) and, in the valley bottom, a Lateglacial–Holocene Lower Terrace and a Holocene Lowermost Terrace. The sediments forming these terraces document a complex history of tectonic uplift, glacio-isostatic rebound, and climatic changes. Notable features include a sequence of alluvial fans and terraces shaped by neotectonic activity, particularly during the Late Quaternary.
{"title":"Deformation of terrace surfaces in the Bystrzyca River valley, central Sudetic Foreland, SW Poland","authors":"Dariusz Krzyszkowski , Lucyna Wachecka-Kotkowska , Marcin Krawczyk , David Bridgland","doi":"10.1016/j.pgeola.2024.09.002","DOIUrl":"10.1016/j.pgeola.2024.09.002","url":null,"abstract":"<div><div>This article addresses the development of Pleistocene terraces in the Bystrzyca River catchment (Sudetic Foreland, Southwestern Poland) in the vicinity of the Sudetic Marginal Fault, within the Roztoka–Mokrzeszów Graben. Nineteen research sites located within the Świdnica Plain are documented in this paper, representative of terraces of the Bystrzyca and its Piława and Witoszówka tributaries, with reporting on analyses of structure, grain size, petrography, quartz-grain morphoscopy, and heavy minerals. The Bystrzyca River, flowing in the largest and deepest valley in the Sowie Mountains, crossing the fault zone and extending into the Sudetic Foreland, has been influenced by significant tectonic and glacial events. During the Middle Pleistocene a fluvial piedmont fan was formed and survives as traces of higher-level (pre-Saalian) terraces. The main fluvial terraces are recognized as follows: an Upper Terrace, from the Saalian, a Middle Terrace from the Upper Pleistocene Last Glacial (Weichselian) and, in the valley bottom, a Lateglacial–Holocene Lower Terrace and a Holocene Lowermost Terrace. The sediments forming these terraces document a complex history of tectonic uplift, glacio-isostatic rebound, and climatic changes. Notable features include a sequence of alluvial fans and terraces shaped by neotectonic activity, particularly during the Late Quaternary.</div></div>","PeriodicalId":49672,"journal":{"name":"Proceedings of the Geologists Association","volume":"135 6","pages":"Pages 639-659"},"PeriodicalIF":1.2,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143152504","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 : 2024-10-01DOI: 10.1016/j.pgeola.2024.08.004
Robin I. Knight
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.
{"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}
Pub Date : 2024-10-01DOI: 10.1016/j.pgeola.2024.08.002
Yingshun Tang , Ming Li , Zhengyu Song , Honghe Xu , Hui Wang , Edmund A. Jarzembowski , Bo Wang
A new archostematan beetle, Brochocoleus sonidensis 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.
{"title":"A new Early Cretaceous ommatine beetle (Insecta: Coleoptera: Archostemata) from Inner Mongolia, China","authors":"Yingshun Tang , Ming Li , Zhengyu Song , Honghe Xu , Hui Wang , Edmund A. Jarzembowski , 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}
Pub Date : 2024-10-01DOI: 10.1016/j.pgeola.2024.03.003
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 Cenomanian (Rotalipora sp. cf. R. cushmani Total Range Zone), the upper part of the Adahri Formation to the Cenomanian–Turonian Transition to the lower Turonian (Whiteinella archaeocretacea Partial Range Zone and Helvetoglobotruncana helvetica Total-Range Zone, respectively), the lower member of the Yabous Formation to the middle Turonian (Marginotruncana sigali Partial Range Zone), and the upper member of the Yabous Formation to the upper Turonian (Marginotruncana schneegansi Partial Range Zone). The Turonian–Coniancian boundary was dated approximately. This biozonation 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 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 sequence stratigraphy has allowed the recognition of three third-order depositional sequences grouped into two megasequences and correlated to a regional scale.
该报告首次描述了奥雷斯山脉北部上元古-下元古碳酸盐岩的地层特征和古环境条件。共确认了四个地层，分别为 Arris、Adahri、Yabous 和 Bou Ouali。浮游有孔虫使我们能够将 Arris 地层的上部和 Adahri 地层的下部归入中-上震旦纪（Rotalipora sp.cushmani Total Range Zone），将 Adahri Formation 的上部归入仙人漫纪-都龙纪过渡到下都龙纪（Whiteinella archaeocretacea Partial Range Zone 和 Helvetoglobotruncana helvetica Total-Range Zone、分别），雅布斯地层下统至都龙纪中统（Marginotruncana sigali 部分范围区），雅布斯地层上统至都龙纪上统（Marginotruncana schneegansi 部分范围区）。都元古代-康熙元年界线的年代大致确定。这种生物区系可与阿尔及利亚境外的几个上震旦纪-下震旦纪地段相关联，主要是在泰西和北方地区。根据野外数据和微成因研究，这些地层被划分为 11 个微成因类型（MT 1 至 MT 11），这些微成因类型根据沉积环境进行了描述，并分为三个主要成因组合（FA 1、FA 2 和 FA 3）：(i) 深陆架-盆地面带；(ii) 边缘沙滩、开放-海洋/限制平台面带；(iii) 外部平台和坡脚/斜坡面带。通过对地层序列的分析，可以确认三个三阶沉积序列，分为两个巨序列，并与区域尺度相关联。
{"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}
Pub Date : 2024-10-01DOI: 10.1016/j.pgeola.2024.08.005
James B. Innes , Mairead M. Rutherford , David R. Bridgland , Ben R. Gearey , Malcolm C. Lillie , Wishart A. Mitchell , Charlotte E. O'Brien , Richard T. Jones , Gareth J. Thompson
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-Ulmus Decline mid-Holocene. Although the calcareous nature of the sediment and lack of terrestrial plant macrofossils precluded radiocarbon dating of sediments pre-dating the Ulmus 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 Betula frequencies, replaced by Juniperus, 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 Ulmus Decline occurs near the top of the profile, after which the assemblage is dominated by Alnus 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 Betula woodland was much better established.
在英格兰东北部蒂斯河和斯威尔河交汇处的一个湖盆遗址 Pepper Arden Bottoms 进行的调查发现了岩石地层、花粉和植物大化石序列，从而可以重建从大冰期间冰期到全新世中期乌尔姆斯衰退后的沉积和植被历史。虽然沉积物的钙质性质和陆生植物大化石的缺乏排除了对榆树衰退之前沉积物进行放射性碳测年的可能性，但花粉分析显示沉积物从腊肠冰期间冰期中期开始积累，湖泊流域直到全新世之前一直植被稀少，木本类群含量较低，禾本科植物和莎草占主导地位。花粉地层中出现了间冰期晚期的寒冷阶段 GI-1b，桦树的频率大幅下降，被杜松取代，耐寒草本植物（主要是禾本科和莎草）的频率上升。在整个拉特格拉冰期地层中，微炭的频率一直很高，这可能表明这里有自然的火灾机制，但全新世则没有微炭，这表明附近几乎没有中石器时代或新石器时代的活动，这一点也从缺乏扰动迹象的花粉中得到了证实。拉特格拉冰期（洛蒙湖）的花粉完全以桧柏科和禾本科花粉为主，很少有乔木和灌木。全新世记录了冰期后嗜热树木的陆续迁移，并确认了前生物涛动和 8.2 ka BP 寒冷事件可能造成的影响。在剖面顶部附近出现了榆树衰退现象，之后随着湖泊陆地化，湖泊被沼泽和桤木林所占据，桤木树群开始占据主导地位。非常开阔的腊特拉冰期植被使该地点跻身英格兰东北部腊特拉冰期林地发展较差的北部地区，与之形成鲜明对比的是，在北约克郡南部的地点，腊特拉冰期的桦树林地发展得要好得多。
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