Pub Date : 2025-12-01DOI: 10.1016/j.pgeola.2025.101148
Orkun Türe, Serhat Tuna Çelikkollu
Structures are typically built on solid-state soils, assuming they will support the loads. However, if these soils are loose and saturated, their strength decreases during earthquakes. If this critical process is not considered during the structural design, the consequences can be catastrophic. Consequently, determination of liquefiable and non-liquefiable soils and mapping their spatial distribution over an area have always been significant tasks in urbanisation especially in regions with high population density. Fethiye Basin, which is located at the edge of the Hellenic Trench, is such a high-density tourist destination with its population exceeding one million during summers. The region is known to be struck by a Ms = 7.1 earthquake in 1957 which resulted in the collapse of almost all of the buildings within the area. Moreover, latest research indicates that the region may be struck by a high magnitude earthquake in the following years and such event will be a significant threat for the residents and the visitors. Accordingly, a liquefaction hazard map of the Fethiye Basin was developed based on Liquefaction Potential Index (LPI) values. The western coastal part of the basin, where population density is high and groundwater is shallow, exhibits high liquefaction susceptibility. In contrast, the eastern part is relatively safe due to deeper groundwater levels.
{"title":"Liquefaction geo-hazard in the Fethiye Basin at the edge of Hellenic Trench","authors":"Orkun Türe, Serhat Tuna Çelikkollu","doi":"10.1016/j.pgeola.2025.101148","DOIUrl":"10.1016/j.pgeola.2025.101148","url":null,"abstract":"<div><div>Structures are typically built on solid-state soils, assuming they will support the loads. However, if these soils are loose and saturated, their strength decreases during earthquakes. If this critical process is not considered during the structural design, the consequences can be catastrophic. Consequently, determination of liquefiable and non-liquefiable soils and mapping their spatial distribution over an area have always been significant tasks in urbanisation especially in regions with high population density. Fethiye Basin, which is located at the edge of the Hellenic Trench, is such a high-density tourist destination with its population exceeding one million during summers. The region is known to be struck by a Ms = 7.1 earthquake in 1957 which resulted in the collapse of almost all of the buildings within the area. Moreover, latest research indicates that the region may be struck by a high magnitude earthquake in the following years and such event will be a significant threat for the residents and the visitors. Accordingly, a liquefaction hazard map of the Fethiye Basin was developed based on Liquefaction Potential Index (LPI) values. The western coastal part of the basin, where population density is high and groundwater is shallow, exhibits high liquefaction susceptibility. In contrast, the eastern part is relatively safe due to deeper groundwater levels.</div></div>","PeriodicalId":49672,"journal":{"name":"Proceedings of the Geologists Association","volume":"136 6","pages":"Article 101148"},"PeriodicalIF":1.3,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145719056","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 : 2025-12-01DOI: 10.1016/j.pgeola.2025.101142
Owain Evans , Cindy Howells , Nathan Wintle , Michael J. Benton
A large jaw of a predatory archosaur from the latest Triassic of South Wales, named Zanclodon cambrensis, has long intrigued vertebrate palaeontologists. Could it be the oldest large theropod dinosaur? Here we reanalyse the specimen based on a new 3D digital reconstruction. We confirm first that it is indeed latest Triassic in age, most likely extracted from sandstones of the Cotham Member of the Lilstock Formation (Penarth Group, Rhaetian). Anatomically it shows features of theropod dinosaurs rather than other large non-dinosaurian predatory archosaurs of the Triassic. It shares general characteristics with European coelophysoids of similar age such as Liliensternus and Dracoraptor but is considerably larger. It is not a megalosauroid, as suggested previously, but it is unclear whether it might be an averostran or tetanuran. Its close similarity to Dilophosaurus suggests that this left-hand mandible specimen represents a more derived basal neotheropod and we assign it to a new genus, as Newtonsaurus cambrensis.
{"title":"Re-assessment of a large archosaur dentary from the Late Triassic of South Wales, United Kingdom","authors":"Owain Evans , Cindy Howells , Nathan Wintle , Michael J. Benton","doi":"10.1016/j.pgeola.2025.101142","DOIUrl":"10.1016/j.pgeola.2025.101142","url":null,"abstract":"<div><div>A large jaw of a predatory archosaur from the latest Triassic of South Wales, named <em>Zanclodon cambrensis</em>, has long intrigued vertebrate palaeontologists. Could it be the oldest large theropod dinosaur? Here we reanalyse the specimen based on a new 3D digital reconstruction. We confirm first that it is indeed latest Triassic in age, most likely extracted from sandstones of the Cotham Member of the Lilstock Formation (Penarth Group, Rhaetian). Anatomically it shows features of theropod dinosaurs rather than other large non-dinosaurian predatory archosaurs of the Triassic. It shares general characteristics with European coelophysoids of similar age such as <em>Liliensternus</em> and <em>Dracoraptor</em> but is considerably larger. It is not a megalosauroid, as suggested previously, but it is unclear whether it might be an averostran or tetanuran. Its close similarity to <em>Dilophosaurus</em> suggests that this left-hand mandible specimen represents a more derived basal neotheropod and we assign it to a new genus, as <em>Newtonsaurus cambrensis</em>.</div></div>","PeriodicalId":49672,"journal":{"name":"Proceedings of the Geologists Association","volume":"136 6","pages":"Article 101142"},"PeriodicalIF":1.3,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145718873","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 : 2025-12-01DOI: 10.1016/j.pgeola.2025.101136
Andrew Davies, Michael D. Simmons
Relative sea-level curves obtained from analysis of the stratigraphic record provide crucial insights into various aspects of the Earth system. In recent years, several studies have employed sediment noise modelling (DYNOT and lag-1 autocorrelation coefficient) of astronomically tuned records to obtain information on changes in water depth and relative sea-level. Many of these studies provide support for aquifer-eustasy by demonstrating an out of phase relationship between relative lake level (from sediment noise modelling) and published eustatic curves. However, few studies have validated the sea/lake level curves derived from sediment noise modelling with independent water depth indicators. Here sediment noise modelling is critically evaluated using data from the Upper Jurassic Kimmeridge Clay Formation of the southern UK, where astronomical forcing has previously been demonstrated. Sediment noise modelling-derived water depth records are compared to detrital quartz-silt concentrations, previously shown to be an excellent proxy for relative sea-level changes through correlation with contemporaneous proximal successions. There is minimal correlation between the sediment noise modelling results and the independent quartz-silt record. Consequently, more research is required to demonstrate the validity of sediment noise modelling as a proxy for water depth change in sedimentary successions. This work implies that support for aquifer-eustasy as a primary driver of short-term, moderate magnitude sea-level change from sediment noise modelling studies should be re-evaluated.
{"title":"An assessment of sediment noise modelling on the Upper Jurassic Kimmeridge Clay: Implications for aquifer-eustasy","authors":"Andrew Davies, Michael D. Simmons","doi":"10.1016/j.pgeola.2025.101136","DOIUrl":"10.1016/j.pgeola.2025.101136","url":null,"abstract":"<div><div>Relative sea-level curves obtained from analysis of the stratigraphic record provide crucial insights into various aspects of the Earth system. In recent years, several studies have employed sediment noise modelling (DYNOT and lag-1 autocorrelation coefficient) of astronomically tuned records to obtain information on changes in water depth and relative sea-level. Many of these studies provide support for aquifer-eustasy by demonstrating an out of phase relationship between relative lake level (from sediment noise modelling) and published eustatic curves. However, few studies have validated the sea/lake level curves derived from sediment noise modelling with independent water depth indicators. Here sediment noise modelling is critically evaluated using data from the Upper Jurassic Kimmeridge Clay Formation of the southern UK, where astronomical forcing has previously been demonstrated. Sediment noise modelling-derived water depth records are compared to detrital quartz-silt concentrations, previously shown to be an excellent proxy for relative sea-level changes through correlation with contemporaneous proximal successions. There is minimal correlation between the sediment noise modelling results and the independent quartz-silt record. Consequently, more research is required to demonstrate the validity of sediment noise modelling as a proxy for water depth change in sedimentary successions. This work implies that support for aquifer-eustasy as a primary driver of short-term, moderate magnitude sea-level change from sediment noise modelling studies should be re-evaluated.</div></div>","PeriodicalId":49672,"journal":{"name":"Proceedings of the Geologists Association","volume":"136 6","pages":"Article 101136"},"PeriodicalIF":1.3,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145718869","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 : 2025-12-01DOI: 10.1016/j.pgeola.2025.101143
Madani Benyoucef , Marcin Krajewski , Sixto Rafael Fernández-López , Imad Bouchemla , Fayçal Mekki , Mariusz A. Salamon , Mohammed Adaci , Mohamed Amine Zaidi , Djamel Belloumou
This study, based on lithostratigraphical and biostratigraphical analyses, focuses on ammonites, trace fossils, and sedimentary facies of the Bajocian Teniet El Klakh Formation in the Ain Sefra area of the Western Saharan Atlas, Algeria. This formation represents a key Middle Jurassic succession within the Maghrebian Tethys realm, marking the transition from the Liassic carbonate platform and the Upper Jurassic coastal–continental clastic deposits. Field observations, combined with microscopic analyses allowed the recognition of thirteen siliciclastic and carbonate facies types (FT1–FT13), each interpreted in terms of its depositional environment. These facies types are grouped into three main facies associations (FA1–FA3), corresponding to distinct palaeoenvironmental settings: (i) lower shoreface to offshore transition, (ii) storm-dominated upper shoreface, and (iii) shoal. The trace fossils Palaeophycus heberti, Paleodictyon strozzii, Protopaleodictyon cf. submontanum, Zoophycos brianteus, Zoophycos cauda-galli, and Zoophycos villae are reported here for the first time from the Bajocian of the Saharan Atlas. Contrary to earlier interpretations, the newly identified ammonite assemblages indicate a Lower to Upper Bajocian age (Humphriesianum and Niortense zones) for the Teniet El Klakh Formation.
本文在岩石地层和生物地层分析的基础上,对阿尔及利亚西撒哈拉地图集Ain Sefra地区Bajocian Teniet El Klakh组的古石、微量化石和沉积相进行了研究。该地层代表了马格里布-特提斯领域内一个关键的中侏罗世演替,标志着从晚侏罗世碳酸盐岩台地到上侏罗世海岸-大陆碎屑沉积的过渡。现场观察结合显微分析,识别出13种硅岩和碳酸盐相类型(FT1-FT13),并根据沉积环境对每种类型进行了解释。这些相类型分为三个主要相组合(FA1-FA3),对应于不同的古环境背景:(i)下滨面向近海过渡,(ii)风暴主导的上滨面,(iii)浅滩。在撒哈拉地图集的巴约西亚地区,首次报道了heberti、strozzii、submontanum、zotopaleodictyon、brianteus、cauda-galli和Zoophycos villae等化石。与先前的解释相反,新鉴定的菊石组合表明Teniet El Klakh组的下至上巴约西亚时代(Humphriesianum和Niortense带)。
{"title":"Stratigraphical and sedimentological insights into the Bajocian (Middle Jurassic) Teniet El Klakh Formation, Western Saharan Atlas, Algeria","authors":"Madani Benyoucef , Marcin Krajewski , Sixto Rafael Fernández-López , Imad Bouchemla , Fayçal Mekki , Mariusz A. Salamon , Mohammed Adaci , Mohamed Amine Zaidi , Djamel Belloumou","doi":"10.1016/j.pgeola.2025.101143","DOIUrl":"10.1016/j.pgeola.2025.101143","url":null,"abstract":"<div><div>This study, based on lithostratigraphical and biostratigraphical analyses, focuses on ammonites, trace fossils, and sedimentary facies of the Bajocian Teniet El Klakh Formation in the Ain Sefra area of the Western Saharan Atlas, Algeria. This formation represents a key Middle Jurassic succession within the Maghrebian Tethys realm, marking the transition from the Liassic carbonate platform and the Upper Jurassic coastal–continental clastic deposits. Field observations, combined with microscopic analyses allowed the recognition of thirteen siliciclastic and carbonate facies types (FT1–FT13), each interpreted in terms of its depositional environment. These facies types are grouped into three main facies associations (FA1–FA3), corresponding to distinct palaeoenvironmental settings: (i) lower shoreface to offshore transition, (ii) storm-dominated upper shoreface, and (iii) shoal. The trace fossils <em>Palaeophycus heberti</em>, <em>Paleodictyon strozzii</em>, <em>Protopaleodictyon</em> cf. <em>submontanum</em>, <em>Zoophycos brianteus</em>, <em>Zoophycos cauda-galli</em>, and <em>Zoophycos villae</em> are reported here for the first time from the Bajocian of the Saharan Atlas. Contrary to earlier interpretations, the newly identified ammonite assemblages indicate a Lower to Upper Bajocian age (Humphriesianum and Niortense zones) for the Teniet El Klakh Formation.</div></div>","PeriodicalId":49672,"journal":{"name":"Proceedings of the Geologists Association","volume":"136 6","pages":"Article 101143"},"PeriodicalIF":1.3,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145719055","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 : 2025-12-01DOI: 10.1016/j.pgeola.2025.101152
Peter Wilson , David Jarman , Maria Miguens-Rodriguez , Derek Fabel
The temporal dynamics of the Robinson rock slope failure (RSF), the largest such feature in the Lake District of northwest England, have been assessed through cosmogenic (10Be) surface-exposure dating of quartz veins on the headscarp/rupture surface and an upper-mid-slope antiscarp. Movement along the headscarp/rupture surface began during the Lateglacial ~ 15.4–14.3 ka, and movement could have continued, incrementally or episodically, until the mid-Holocene ~ 4.6 ka. Displacement rates for the headscarp/rupture surface averaged over that time are in the range 3–4.5 mm/a. These are the first rates to be reported for an RSF in Britain and Ireland. Ages from the upper-mid-slope antiscarp (~ 8–6.5 ka) indicate early-mid-Holocene movement, although 10Be inheritance may have aged these samples somewhat. Reasons for RSF activity at Robinson at those times are complex, but probably involved paraglacial stress release augmented by the concentrated erosion of bedrock in a trough below a glacial breach, along with the structural characteristics of the local bedrock. The cosmogenic ages suggest that other RSFs in this area may have a longer history of instability than hitherto thought.
{"title":"Late Quaternary evolution of a large rock slope deformation (Robinson, English Lake District) – a first such exploration by cosmogenic exposure dating in the British mountains","authors":"Peter Wilson , David Jarman , Maria Miguens-Rodriguez , Derek Fabel","doi":"10.1016/j.pgeola.2025.101152","DOIUrl":"10.1016/j.pgeola.2025.101152","url":null,"abstract":"<div><div>The temporal dynamics of the Robinson rock slope failure (RSF), the largest such feature in the Lake District of northwest England, have been assessed through cosmogenic (<sup>10</sup>Be) surface-exposure dating of quartz veins on the headscarp/rupture surface and an upper-mid-slope antiscarp. Movement along the headscarp/rupture surface began during the Lateglacial ~<!--> <!-->15.4–14.3 ka, and movement could have continued, incrementally or episodically, until the mid-Holocene ~<!--> <!-->4.6 ka. Displacement rates for the headscarp/rupture surface averaged over that time are in the range 3–4.5 mm/a. These are the first rates to be reported for an RSF in Britain and Ireland. Ages from the upper-mid-slope antiscarp (~<!--> <!-->8–6.5 ka) indicate early-mid-Holocene movement, although <sup>10</sup>Be inheritance may have aged these samples somewhat. Reasons for RSF activity at Robinson at those times are complex, but probably involved paraglacial stress release augmented by the concentrated erosion of bedrock in a trough below a glacial breach, along with the structural characteristics of the local bedrock. The cosmogenic ages suggest that other RSFs in this area may have a longer history of instability than hitherto thought.</div></div>","PeriodicalId":49672,"journal":{"name":"Proceedings of the Geologists Association","volume":"136 6","pages":"Article 101152"},"PeriodicalIF":1.3,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145719060","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 : 2025-12-01DOI: 10.1016/j.pgeola.2025.101140
James R. Thomka
The bioerosional ichnogenus Lacrimichnus is herein described from the Upper Carboniferous (Pennsylvanian) Ames Limestone Member of the Glenshaw Formation of eastern Ohio, USA, where it occurs in a basal plate belonging to a cromyocrinid cladid crinoid. This trace is generally regarded as a ‘homing scar’ produced by gastropods, including platyceratids, which are frequently parasitic on crinoid hosts. Although North American cromyocrinids are not known to serve as common hosts to platyceratids, this occurrence provides suggestive evidence that a cromyocrinid–platyceratid relationship may have existed in North America, similar to what has been documented elsewhere. The present specimen of Lacrimichnus represents a rare example of this ichnogenus from Pennsylvanian strata, the first from a North American cromyocrinid crinoid, and the first example from an isolated crinoid ossicle. It is recommended that Lacrimichnus be consistently documented and recorded as such instead of ‘platyceratid attachment scars’ or similar phrases.
{"title":"Lacrimichnus in a cromyocrinid crinoid from the Upper Carboniferous of Ohio, USA, and its bearing on parasitism of Palaeozoic crinoids","authors":"James R. Thomka","doi":"10.1016/j.pgeola.2025.101140","DOIUrl":"10.1016/j.pgeola.2025.101140","url":null,"abstract":"<div><div>The bioerosional ichnogenus <em>Lacrimichnus</em> is herein described from the Upper Carboniferous (Pennsylvanian) Ames Limestone Member of the Glenshaw Formation of eastern Ohio, USA, where it occurs in a basal plate belonging to a cromyocrinid cladid crinoid. This trace is generally regarded as a ‘homing scar’ produced by gastropods, including platyceratids, which are frequently parasitic on crinoid hosts. Although North American cromyocrinids are not known to serve as common hosts to platyceratids, this occurrence provides suggestive evidence that a cromyocrinid–platyceratid relationship may have existed in North America, similar to what has been documented elsewhere. The present specimen of <em>Lacrimichnus</em> represents a rare example of this ichnogenus from Pennsylvanian strata, the first from a North American cromyocrinid crinoid, and the first example from an isolated crinoid ossicle. It is recommended that <em>Lacrimichnus</em> be consistently documented and recorded as such instead of ‘platyceratid attachment scars’ or similar phrases.</div></div>","PeriodicalId":49672,"journal":{"name":"Proceedings of the Geologists Association","volume":"136 6","pages":"Article 101140"},"PeriodicalIF":1.3,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145718872","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 : 2025-12-01DOI: 10.1016/j.pgeola.2025.101149
Charles W. Helm , Given Banda , Hayley C. Cawthra , Richard M. Cowling , Jan C. De Vynck , Mark G. Dixon , Pieter-Jan Gräbe , Jean A. Malan , Willo M. Stear , Guy H.H. Thesen
Aeolianites of the Wankoe Formation, of Pliocene age, are encountered in the southern Cape of South Africa. Until now, and in contrast with the prevalence of vertebrate tracksites in the coastal Pleistocene Waenhuiskrans Formation, no vertebrate tracks have been identified in the Wankoe Formation. However, our studies indicate that the formation is richly fossiliferous and that vertebrate tracks are commonly encountered in suitable areas, although non-karstified outcrops are in general sparsely distributed. Whilst many of the tracks are only evident in profile, a vertebrate trackway in the Grootbos Private Nature Reserve, for example, comprises five tracks preserved in plan view. Although identification to trackmaker species is not possible, several plausible trackmaker taxa can be postulated. In combination, these tracksites appear to contain the first recorded Pliocene vertebrate tracks described from southern Africa. Pedestalling of tracks has been noted at two sites, suggesting that this unusual form of track preservation could be sought elsewhere in Wankoe Formation deposits. A dedicated search, focusing on areas with substantial cliff exposures, should yield further discoveries.
{"title":"Vertebrate tracks in Pliocene aeolianite deposits of the Wankoe Formation, Western Cape Province, South Africa","authors":"Charles W. Helm , Given Banda , Hayley C. Cawthra , Richard M. Cowling , Jan C. De Vynck , Mark G. Dixon , Pieter-Jan Gräbe , Jean A. Malan , Willo M. Stear , Guy H.H. Thesen","doi":"10.1016/j.pgeola.2025.101149","DOIUrl":"10.1016/j.pgeola.2025.101149","url":null,"abstract":"<div><div>Aeolianites of the Wankoe Formation, of Pliocene age, are encountered in the southern Cape of South Africa. Until now, and in contrast with the prevalence of vertebrate tracksites in the coastal Pleistocene Waenhuiskrans Formation, no vertebrate tracks have been identified in the Wankoe Formation. However, our studies indicate that the formation is richly fossiliferous and that vertebrate tracks are commonly encountered in suitable areas, although non-karstified outcrops are in general sparsely distributed. Whilst many of the tracks are only evident in profile, a vertebrate trackway in the Grootbos Private Nature Reserve, for example, comprises five tracks preserved in plan view. Although identification to trackmaker species is not possible, several plausible trackmaker taxa can be postulated. In combination, these tracksites appear to contain the first recorded Pliocene vertebrate tracks described from southern Africa. Pedestalling of tracks has been noted at two sites, suggesting that this unusual form of track preservation could be sought elsewhere in Wankoe Formation deposits. A dedicated search, focusing on areas with substantial cliff exposures, should yield further discoveries.</div></div>","PeriodicalId":49672,"journal":{"name":"Proceedings of the Geologists Association","volume":"136 6","pages":"Article 101149"},"PeriodicalIF":1.3,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145719057","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 : 2025-12-01DOI: 10.1016/j.pgeola.2025.101138
Yannan Lü, Xiaoxue Du, Leidan Ning, Qianqi Zhang
Three new procercopid species, Stellularis bifurcata Ning & Zhang sp. nov., Stellularis latimaculata Du & Zhang sp. nov. and Stellularis pulchra Lü & Zhang sp. nov., are established from the Lower Cretaceous Jiufotang Formation in Kazuo County, western Liaoning Province, NE China. The two-branched vein M in S. bifurcata sp. nov., the unique patches in S. latimaculata sp. nov. and the two-branched vein CuA1 in S. pulchra sp. nov. constitute the diagnostic features of each species separately. The new species augment the diversity of genus Stellularis Chen D., Yao & Ren, 2015 and S. bifurcata sp. nov. is the longest known tegmen in the genus Stellularis.
在辽西卡左县下白垩统九福塘组发现了三种原足类新种,即双歧星aris Ning &; Zhang sp. nov、latimaculata Du & Zhang sp. nov和pulchra Stellularis Lü &; Zhang sp. nov。two-branched静脉M s bifurcata sp. 11月,在美国独特的补丁latimaculata sp. 11月和美国two-branched静脉CuA1 pulchra sp. 11月分别构成每个物种的诊断特征。Chen D., Yao & Ren, 2015, S. bifurcata sp. 11 .是目前已知最长的被盖星属植物。
{"title":"New species of Stellularis (Hemiptera: Cicadomorpha: Procercopidae) from the Lower Cretaceous Jiufotang Formation in northeastern China","authors":"Yannan Lü, Xiaoxue Du, Leidan Ning, Qianqi Zhang","doi":"10.1016/j.pgeola.2025.101138","DOIUrl":"10.1016/j.pgeola.2025.101138","url":null,"abstract":"<div><div>Three new procercopid species, <em>Stellularis bifurcata</em> Ning & Zhang sp. nov., <em>Stellularis latimaculata</em> Du & Zhang sp. nov. and <em>Stellularis pulchra</em> Lü & Zhang sp. nov., are established from the Lower Cretaceous Jiufotang Formation in Kazuo County, western Liaoning Province, NE China. The two-branched vein M in <em>S. bifurcata</em> sp. nov., the unique patches in <em>S. latimaculata</em> sp. nov. and the two-branched vein CuA<sub>1</sub> in <em>S. pulchra</em> sp. nov. constitute the diagnostic features of each species separately. The new species augment the diversity of genus <em>Stellularis</em> Chen D., Yao & Ren, 2015 and <em>S. bifurcata</em> sp. nov. is the longest known tegmen in the genus <em>Stellularis</em>.</div></div>","PeriodicalId":49672,"journal":{"name":"Proceedings of the Geologists Association","volume":"136 6","pages":"Article 101138"},"PeriodicalIF":1.3,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145718871","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}
The Plio-Quaternary volcanism of Saka, located in the Guercif region in northeastern Morocco, holds significant geological interest in the study of mantle-derived magma and magmatic differentiation processes. Its historical activity has been mainly effusive, producing a variety of volcanic rocks ranging from ultrabasic to acidic compositions. In this study, around forty samples were collected, prepared as polished thin sections, and analyzed under a petrographic microscope. Twelve representative samples were selected for major and trace element analyses, carried out by inductively coupled plasma-mass spectrometry (ICP-MS) with laser ablation. The volcanic rocks of Saka are primarily composed of basanite, basalt, trachy-andesite, and trachyte, forming a strongly differentiated alkaline series evolving from alkaline basalts to trachytes. Geochemical analyses reveal enrichment in SiO2, Al₂O₃, Na₂O, and K₂O, and depletion in MgO and CaO, indicating a process of assimilation and fractional crystallization. A good correlation is observed between certain trace elements (U, Nb, Ta, La, Zr, Hf, Yb, Rb, Y) and the differentiation index. The Saka lavas are mantle-derived and exhibit characteristics like ocean island basalts (OIBs) with HIMU (high μ, μ = 238U/204Pb) signatures. Geotectonically, Saka volcanism developed in an intraplate extensional setting, classified as Within-Plate Basalt (WPB) and Within-Plate Volcanic Zone (WPVZ), likely related to lithospheric thinning and subduction rollback in the Alboran region, favouring mantle decompression and magma ascent along pre-existing faults.
{"title":"Petrogenesis of lava from Saka (Guercif, Morocco): Source characterization and magma evolution","authors":"Abdallah Elaaraj , Maham Eboubekrine Sedigh , Ali Lhachmi , Hassan Tabyaoui , Abdennabi Alitane , Massimo Tiepolo , Iliass Naouadir","doi":"10.1016/j.pgeola.2025.101151","DOIUrl":"10.1016/j.pgeola.2025.101151","url":null,"abstract":"<div><div>The Plio-Quaternary volcanism of Saka, located in the Guercif region in northeastern Morocco, holds significant geological interest in the study of mantle-derived magma and magmatic differentiation processes. Its historical activity has been mainly effusive, producing a variety of volcanic rocks ranging from ultrabasic to acidic compositions. In this study, around forty samples were collected, prepared as polished thin sections, and analyzed under a petrographic microscope. Twelve representative samples were selected for major and trace element analyses, carried out by inductively coupled plasma-mass spectrometry (ICP-MS) with laser ablation. The volcanic rocks of Saka are primarily composed of basanite, basalt, trachy-andesite, and trachyte, forming a strongly differentiated alkaline series evolving from alkaline basalts to trachytes. Geochemical analyses reveal enrichment in SiO<sub>2</sub>, Al₂O₃, Na₂O, and K₂O, and depletion in MgO and CaO, indicating a process of assimilation and fractional crystallization. A good correlation is observed between certain trace elements (U, Nb, Ta, La, Zr, Hf, Yb, Rb, Y) and the differentiation index. The Saka lavas are mantle-derived and exhibit characteristics like ocean island basalts (OIBs) with HIMU (high <em>μ</em>, μ = <sup>238</sup>U/<sup>204</sup>Pb) signatures. Geotectonically, Saka volcanism developed in an intraplate extensional setting, classified as Within-Plate Basalt (WPB) and Within-Plate Volcanic Zone (WPVZ), likely related to lithospheric thinning and subduction rollback in the Alboran region, favouring mantle decompression and magma ascent along pre-existing faults.</div></div>","PeriodicalId":49672,"journal":{"name":"Proceedings of the Geologists Association","volume":"136 6","pages":"Article 101151"},"PeriodicalIF":1.3,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145719059","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 : 2025-12-01DOI: 10.1016/j.pgeola.2025.101137
Iliass Naouadir , Samira Adil , El Hassane Chellai , Mohammed Ettaki , Abdallah Elaaraj , Abdennabi Alitane , Mario Parise , Márton Veress
The El Menzel Causse, located in the northern Middle Atlas, showcases a remarkable yet largely underexplored karstic geodiversity. The richness and uniqueness of this region, particularly its exokarstic and endokarstic features, as well as its position at the boundary between the Tabular and Folded Middle Atlas, motivated our study. This research marks the first comprehensive analysis of the genesis and evolution of both endokarstic and exokarstic forms within the Middle Atlas. The observed karstic features, such as lapies, poljes, uvalas, caves, dry valleys, and karst springs, illustrate a wide morphological diversity. By combining field surveys, petrographic analysis, and advanced techniques such as satellite data, we conducted a detailed study of karstic processes and the factors influencing karstogenesis. Our results in the Middle Atlas highlight the complexity and interdependence of the factors involved, including climatic, pedological, lithological, stratigraphic, petrographic, morphostructural, hydrological, paleogeographic, and geodynamic elements. The convergence of these factors has led to a diverse array of karstic forms, shaping the distinct landscape of the Middle Atlas. In conclusion, this multidisciplinary study offers new insights into the mechanisms of karstic geodiversity in the region. Our findings provide valuable perspectives not only for understanding the karsts of the Moroccan Atlas but also for other similar orogenic belts, such as the Alps, underscoring the importance of continued research in this field.
El Menzel Causse位于阿特拉斯中部北部,展示了一个非凡的,但在很大程度上未被开发的岩溶地质多样性。该地区的丰富性和独特性,特别是其外岩溶和内岩溶的特征,以及其在中地图集和折叠地图集之间的位置,促使我们进行研究。这项研究首次全面分析了中阿特拉斯地区内岩溶和外岩溶形式的成因和演化。观察到的岩溶特征,如青玉、水柱、洞、干谷和岩溶泉,说明了广泛的形态多样性。结合野外调查、岩石学分析和卫星资料等先进技术,对岩溶过程及影响岩溶形成的因素进行了详细研究。我们在中阿特拉斯的结果突出了所涉及因素的复杂性和相互依赖性,包括气候、土壤学、岩性、地层、岩石学、形态构造、水文、古地理和地球动力学因素。这些因素的融合导致了喀斯特形式的多样化,塑造了中阿特拉斯独特的景观。综上所述,该多学科研究为该地区岩溶地质多样性的形成机制提供了新的认识。我们的发现不仅为了解摩洛哥阿特拉斯的岩溶提供了有价值的视角,也为其他类似的造山带,如阿尔卑斯山,提供了有价值的视角,强调了在这一领域继续研究的重要性。
{"title":"Analysis of karst factors and paleoenvironmental significance of endo- and exokarst landforms in the Middle Atlas of Morocco","authors":"Iliass Naouadir , Samira Adil , El Hassane Chellai , Mohammed Ettaki , Abdallah Elaaraj , Abdennabi Alitane , Mario Parise , Márton Veress","doi":"10.1016/j.pgeola.2025.101137","DOIUrl":"10.1016/j.pgeola.2025.101137","url":null,"abstract":"<div><div>The El Menzel Causse, located in the northern Middle Atlas, showcases a remarkable yet largely underexplored karstic geodiversity. The richness and uniqueness of this region, particularly its exokarstic and endokarstic features, as well as its position at the boundary between the Tabular and Folded Middle Atlas, motivated our study. This research marks the first comprehensive analysis of the genesis and evolution of both endokarstic and exokarstic forms within the Middle Atlas. The observed karstic features, such as lapies, poljes, uvalas, caves, dry valleys, and karst springs, illustrate a wide morphological diversity. By combining field surveys, petrographic analysis, and advanced techniques such as satellite data, we conducted a detailed study of karstic processes and the factors influencing karstogenesis. Our results in the Middle Atlas highlight the complexity and interdependence of the factors involved, including climatic, pedological, lithological, stratigraphic, petrographic, morphostructural, hydrological, paleogeographic, and geodynamic elements. The convergence of these factors has led to a diverse array of karstic forms, shaping the distinct landscape of the Middle Atlas. In conclusion, this multidisciplinary study offers new insights into the mechanisms of karstic geodiversity in the region. Our findings provide valuable perspectives not only for understanding the karsts of the Moroccan Atlas but also for other similar orogenic belts, such as the Alps, underscoring the importance of continued research in this field.</div></div>","PeriodicalId":49672,"journal":{"name":"Proceedings of the Geologists Association","volume":"136 6","pages":"Article 101137"},"PeriodicalIF":1.3,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145718870","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}