Pub Date : 2022-05-17DOI: 10.37570/bgsd-2022-71-02
B. Lauridsen, Stefanie Lode, E. Sheldon, P. Frykman, K. Anderskouv, J. Ineson
Understanding of the shallow shelf system in the Danish Basin during the Early Cretaceous has benefitted significantly from studying the previously overlooked Hauterivian–Aptian section of the Vedsted Formation of the Vinding-1 drill core. The presence of chalks in this section demonstrates that carbonate-rich pelagic sediment accumulated locally in the siliciclastic-dominated Danish Basin and that benthic carbonate production was insignificant. The area was not a carbonate platform in the Early Cretaceous and does not indicate any reworked carbonate supply from platform environments in the vicinity. The scarcity of benthic macrofossils in the cored section is due to the lack of a specialised boreal chalk fauna at that time, and the adjacent nearshore environment apparently did not support any substantial benthic carbonate production. A revised biostratigraphy of the cored section is presented based primarily on calcareous nannofossils, supported by foraminifera, ostracods, and belemnites. Four lithofacies describe the spectrum from marlstone to slightly marly chalk, and the facies succession characterises four depositional units recording two discrete transgressive–regressive cycles. The study provides a depositional record that permits sequence stratigraphic correlation to the Valdemar and Adda Fields in the Central Graben.
{"title":"Lower Cretaceous (Hauterivian–Aptian) pelagic carbonates in the Danish Basin: new data from the Vinding-1 well, central Jylland, Denmark.","authors":"B. Lauridsen, Stefanie Lode, E. Sheldon, P. Frykman, K. Anderskouv, J. Ineson","doi":"10.37570/bgsd-2022-71-02","DOIUrl":"https://doi.org/10.37570/bgsd-2022-71-02","url":null,"abstract":"Understanding of the shallow shelf system in the Danish Basin during the Early Cretaceous has benefitted significantly from studying the previously overlooked Hauterivian–Aptian section of the Vedsted Formation of the Vinding-1 drill core. The presence of chalks in this section demonstrates that carbonate-rich pelagic sediment accumulated locally in the siliciclastic-dominated Danish Basin and that benthic carbonate production was insignificant. The area was not a carbonate platform in the Early Cretaceous and does not indicate any reworked carbonate supply from platform environments in the vicinity. The scarcity of benthic macrofossils in the cored section is due to the lack of a specialised boreal chalk fauna at that time, and the adjacent nearshore environment apparently did not support any substantial benthic carbonate production. A revised biostratigraphy of the cored section is presented based primarily on calcareous nannofossils, supported by foraminifera, ostracods, and belemnites. Four lithofacies describe the spectrum from marlstone to slightly marly chalk, and the facies succession characterises four depositional units recording two discrete transgressive–regressive cycles. The study provides a depositional record that permits sequence stratigraphic correlation to the Valdemar and Adda Fields in the Central Graben.","PeriodicalId":55310,"journal":{"name":"Bulletin of the Geological Society of Denmark","volume":null,"pages":null},"PeriodicalIF":1.2,"publicationDate":"2022-05-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48887042","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 : 2022-05-11DOI: 10.37570/bgsd-2022-70-07
O. Bennike, P. Astrup, B. Odgaard, C. Pearce, P. Wiberg‐Larsen
The Brabrand Sø area west of Aarhus in eastern Jylland, Denmark, was deglaciated about 18 000 to 17 000 years ago. Coring in the present-day lake area revealed Early Holocene stream deposits overlain by marine deposits. The area was transgressed by the sea at c. 8500 cal. years BP and a 12 km long, narrow fjord was formed. In the beginning, the fjord housed a species-poor marine or brackish-water fauna with molluscs Hydrobia sp. (mudsnail), Littorina littorea (winkle), Mytilus edulis (blue mussel) and Cerastoderma sp. (cockle). This phase was followed by a phase during which the fjord housed a species-rich fauna that included Ostrea edulis (European flat oyster) and Ruditapes decussatus (palourde clam). During this phase the salinity and summer water temperatures were higher than in present day Aarhus Bugt and we also see evidence for strong bottom currents. This phase was probably characterised by a fairly large tidal amplitude. Two radiocarbon ages of O. edulis shells of c. 6250 and 6700 cal. years BP indicate that such conditions peaked during the period of the Ertebølle culture. The high-salinity phase was followed by a phase with a more species-poor fauna, this phase was also characterised by a high sedimentation rate – a feature seen in other fjords in the region. We suggest that the shift could be due to a decrease in tidal amplitude. Brabrand Fjord was eventually transformed into a lake due to land uplift and closure of the connection to Aarhus Bugt due to longshore sediment transport but the timing of the transition from fjord to lake is still unknown.
{"title":"Holocene development of Brabrand Fjord, eastern Jylland, Denmark.","authors":"O. Bennike, P. Astrup, B. Odgaard, C. Pearce, P. Wiberg‐Larsen","doi":"10.37570/bgsd-2022-70-07","DOIUrl":"https://doi.org/10.37570/bgsd-2022-70-07","url":null,"abstract":"The Brabrand Sø area west of Aarhus in eastern Jylland, Denmark, was deglaciated about 18 000 to 17 000 years ago. Coring in the present-day lake area revealed Early Holocene stream deposits overlain by marine deposits. The area was transgressed by the sea at c. 8500 cal. years BP and a 12 km long, narrow fjord was formed. In the beginning, the fjord housed a species-poor marine or brackish-water fauna with molluscs Hydrobia sp. (mudsnail), Littorina littorea (winkle), Mytilus edulis (blue mussel) and Cerastoderma sp. (cockle). This phase was followed by a phase during which the fjord housed a species-rich fauna that included Ostrea edulis (European flat oyster) and Ruditapes decussatus (palourde clam). During this phase the salinity and summer water temperatures were higher than in present day Aarhus Bugt and we also see evidence for strong bottom currents. This phase was probably characterised by a fairly large tidal amplitude. Two radiocarbon ages of O. edulis shells of c. 6250 and 6700 cal. years BP indicate that such conditions peaked during the period of the Ertebølle culture. The high-salinity phase was followed by a phase with a more species-poor fauna, this phase was also characterised by a high sedimentation rate – a feature seen in other fjords in the region. We suggest that the shift could be due to a decrease in tidal amplitude. Brabrand Fjord was eventually transformed into a lake due to land uplift and closure of the connection to Aarhus Bugt due to longshore sediment transport but the timing of the transition from fjord to lake is still unknown.","PeriodicalId":55310,"journal":{"name":"Bulletin of the Geological Society of Denmark","volume":null,"pages":null},"PeriodicalIF":1.2,"publicationDate":"2022-05-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49431827","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 : 2022-04-22DOI: 10.37570/bgsd-2022-70-06
J. S. Peel, Artem V. Kouchinsky
Diverse assemblages of helcionelloid molluscs and mollusc-like microfossils are described from the upper Henson Gletscher Formation (Cambrian, Miaolingian Series, Wuliuan Stage) of Lauge Koch Land and western Peary Land, North Greenland (Laurentia). The fauna compares closely to an assemblage of similar age from the Coonigan Formation of Australia, although the latter is preserved as silica replicas while the North Greenland fossils are dominantly preserved as phosphatized internal moulds. These internal moulds often retain a detailed impression of the inner surface of the shell, with a fine pitted texture typically present. Prominent deep grooves on the sub-apical surface in the erect helcionellids Dorispira and Erugoconus, corresponding to ridges on the shell interior, seem to be associated with control of water flow through the mantle cavity. Well-developed shell pores, preserved as tubercles on the internal mould, are common in species of the laterally compressed Mellopegma. New taxa: Dorispira avannga sp. nov., Dorispira septentrionalis sp. nov., Dorispira tavsenensis sp. nov., Dorispira tippik sp. nov., Erugoconus acuminatus gen. et sp. nov., Scenella? siku sp. nov., Sermeqiconus gen. nov., Tavseniconus erectus gen. et sp. nov., Vendrascospira troelseni gen. et sp. nov., Vendrascospira frykmani gen. et sp. nov.
在Lauge Koch Land和北格陵兰岛(Laurentia)西部Peary Land的上Henson Gletscher组(寒武系，妙岭系，五流期)中描述了不同的helcionelloid软体动物和类软体动物微化石组合。这些动物群与澳大利亚库尼根组的相似年龄的组合非常接近，尽管后者被保存为硅复制品，而北格陵兰的化石主要被保存为磷化的内部霉菌。这些内部模具通常保留了外壳内表面的详细印象，通常具有精细的麻点纹理。直立helcionellids Dorispira和Erugoconus的亚顶端表面上有突出的深沟槽，与壳内部的脊相对应，似乎与通过地幔腔的水流控制有关。发育良好的壳孔，在内部霉菌上以结节的形式保存，在侧向压缩的千层赘生物中很常见。新分类群:avannga Dorispira sp. nov.、septentrionalis sp. nov.、tavsenensis sp. nov.、tippik sp. nov.、Erugoconus acuminatus gen. et sp. nov.、Scenella?siku sp. nov, Sermeqiconus gen. nov, Tavseniconus erectus gen. et nov, Vendrascospira troelseni gen. et nov, Vendrascospira frykmani gen. et nov。
{"title":"Middle Cambrian (Miaolingian Series, Wuliuan Stage) molluscs and mollusc-like microfossils from North Greenland (Laurentia).","authors":"J. S. Peel, Artem V. Kouchinsky","doi":"10.37570/bgsd-2022-70-06","DOIUrl":"https://doi.org/10.37570/bgsd-2022-70-06","url":null,"abstract":"Diverse assemblages of helcionelloid molluscs and mollusc-like microfossils are described from the upper Henson Gletscher Formation (Cambrian, Miaolingian Series, Wuliuan Stage) of Lauge Koch Land and western Peary Land, North Greenland (Laurentia). The fauna compares closely to an assemblage of similar age from the Coonigan Formation of Australia, although the latter is preserved as silica replicas while the North Greenland fossils are dominantly preserved as phosphatized internal moulds. These internal moulds often retain a detailed impression of the inner surface of the shell, with a fine pitted texture typically present. Prominent deep grooves on the sub-apical surface in the erect helcionellids Dorispira and Erugoconus, corresponding to ridges on the shell interior, seem to be associated with control of water flow through the mantle cavity. Well-developed shell pores, preserved as tubercles on the internal mould, are common in species of the laterally compressed Mellopegma. New taxa: Dorispira avannga sp. nov., Dorispira septentrionalis sp. nov., Dorispira tavsenensis sp. nov., Dorispira tippik sp. nov., Erugoconus acuminatus gen. et sp. nov., Scenella? siku sp. nov., Sermeqiconus gen. nov., Tavseniconus erectus gen. et sp. nov., Vendrascospira troelseni gen. et sp. nov., Vendrascospira frykmani gen. et sp. nov.","PeriodicalId":55310,"journal":{"name":"Bulletin of the Geological Society of Denmark","volume":null,"pages":null},"PeriodicalIF":1.2,"publicationDate":"2022-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46810629","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 : 2022-04-08DOI: 10.37570/bgsd-2022-70-05
G. Carnevale, W. Schwarzhans, A. Schrøder, B. Lindow
A conger eel (Anguilliformes, Congridae) is described from the lower Lutetian concretionary nodules of the Lillebælt Clay Formation exposed at Trelde Næs, eastern Jutland, based on two partially complete articulated cranial skeletons. One of the cranial specimens exhibits an otolith void from which a cast was taken, used by Schwarzhans (2007) to describe the extinct Pseudoxenomystax treldeensis, which is placed herein within the new genus Smithconger gen. nov. Smithconger treldeensis (Schwarzhans, 2007) is characterized by well-developed lateral processes on the frontals, supraoccipital crest absent, sphenotic spine rather large, anteriorly pointed and exposed on the flattened surface of the skull roof, otic bullae considerably reduced, maxilla almost straight and distally pointed, maxillary and dentary teeth numerous and arranged in multiple rows, dentary with slightly convex ventral profile, opercle with smooth posterior margin and subopercle short. The otoliths of Smithconger treldeensis show high dorsal rim, broad and deep dorsal depression, no ventral furrow, sulcus straight, shallow, centrally positioned with anteriorly reduced colliculum, and ostial channel at anterior tip of colliculum short, not reaching the predorsal rim. The otolith-based species Bathycongrus waihaoensis Schwarzhans, 2019 from the Kaiatan (Bartonian/Priabonian) of New Zealand is also assigned to the genus Smithconger. Smithconger is tentatively referred to the congrid subfamily Congrinae due to the lack of hypohyals in the hyoid bar. This new Eocene genus of conger eel shows a certain degree of similarity with the extant Bassanago. The diversity and relationships of other Eocene congrids is also briefly discussed.
{"title":"An Eocene conger eel (Teleostei, Anguilliformes) from the Lillebælt Clay Formation, Denmark","authors":"G. Carnevale, W. Schwarzhans, A. Schrøder, B. Lindow","doi":"10.37570/bgsd-2022-70-05","DOIUrl":"https://doi.org/10.37570/bgsd-2022-70-05","url":null,"abstract":"A conger eel (Anguilliformes, Congridae) is described from the lower Lutetian concretionary nodules of the Lillebælt Clay Formation exposed at Trelde Næs, eastern Jutland, based on two partially complete articulated cranial skeletons. One of the cranial specimens exhibits an otolith void from which a cast was taken, used by Schwarzhans (2007) to describe the extinct Pseudoxenomystax treldeensis, which is placed herein within the new genus Smithconger gen. nov. Smithconger treldeensis (Schwarzhans, 2007) is characterized by well-developed lateral processes on the frontals, supraoccipital crest absent, sphenotic spine rather large, anteriorly pointed and exposed on the flattened surface of the skull roof, otic bullae considerably reduced, maxilla almost straight and distally pointed, maxillary and dentary teeth numerous and arranged in multiple rows, dentary with slightly convex ventral profile, opercle with smooth posterior margin and subopercle short. The otoliths of Smithconger treldeensis show high dorsal rim, broad and deep dorsal depression, no ventral furrow, sulcus straight, shallow, centrally positioned with anteriorly reduced colliculum, and ostial channel at anterior tip of colliculum short, not reaching the predorsal rim. The otolith-based species Bathycongrus waihaoensis Schwarzhans, 2019 from the Kaiatan (Bartonian/Priabonian) of New Zealand is also assigned to the genus Smithconger. Smithconger is tentatively referred to the congrid subfamily Congrinae due to the lack of hypohyals in the hyoid bar. This new Eocene genus of conger eel shows a certain degree of similarity with the extant Bassanago. The diversity and relationships of other Eocene congrids is also briefly discussed.","PeriodicalId":55310,"journal":{"name":"Bulletin of the Geological Society of Denmark","volume":null,"pages":null},"PeriodicalIF":1.2,"publicationDate":"2022-04-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46897128","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 : 2022-03-30DOI: 10.37570/bgsd-2022-70-04
O. Bennike, Lone Claudi-Hansen, Betina Magnussen, P. Wiberg‐Larsen
Studies of macrofossils indicate that the vegetation near Regstrup in north-west Sjælland, Denmark, from c. 13 600 to 13 500 cal. years BP was dominated by dwarf-shrub heaths. Betula pubescens (downy birch) arrived at c. 13 500 cal. years BP and became common after c. 13 200 cal. years BP. Open forests with B. pubescens and Populus tremula (aspen) dominated until c. 12 500 cal. years BP, indicating that an Allerød-type environment persisted for c. 350 years after the cooling at the onset of the Younger Dryas, which is dated to c. 12 850 years BP in ice cores from Green-land. Betula nana was common after c. 12 500 cal. years BP, indicating a return to a tundra-like landscape with dwarf-shrub heaths. The fauna included Rangifer taran-dus (reindeer), Castor fiber (Eurasian beaver) and possibly Lemmus lemmus (Norway lemming). The lake deposits contain remains of many species of aquatic plants and animals, including three species of fish. The flora and fauna indicate that the lake water was fairly nutrient-rich and alkaline.
{"title":"Macrofossil studies of Lateglacial sediments from Regstrup, north-west Sjælland, Denmark","authors":"O. Bennike, Lone Claudi-Hansen, Betina Magnussen, P. Wiberg‐Larsen","doi":"10.37570/bgsd-2022-70-04","DOIUrl":"https://doi.org/10.37570/bgsd-2022-70-04","url":null,"abstract":"Studies of macrofossils indicate that the vegetation near Regstrup in north-west Sjælland, Denmark, from c. 13 600 to 13 500 cal. years BP was dominated by dwarf-shrub heaths. Betula pubescens (downy birch) arrived at c. 13 500 cal. years BP and became common after c. 13 200 cal. years BP. Open forests with B. pubescens and Populus tremula (aspen) dominated until c. 12 500 cal. years BP, indicating that an Allerød-type environment persisted for c. 350 years after the cooling at the onset of the Younger Dryas, which is dated to c. 12 850 years BP in ice cores from Green-land. Betula nana was common after c. 12 500 cal. years BP, indicating a return to a tundra-like landscape with dwarf-shrub heaths. The fauna included Rangifer taran-dus (reindeer), Castor fiber (Eurasian beaver) and possibly Lemmus lemmus (Norway lemming). The lake deposits contain remains of many species of aquatic plants and animals, including three species of fish. The flora and fauna indicate that the lake water was fairly nutrient-rich and alkaline.","PeriodicalId":55310,"journal":{"name":"Bulletin of the Geological Society of Denmark","volume":null,"pages":null},"PeriodicalIF":1.2,"publicationDate":"2022-03-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43468161","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 : 2022-03-23DOI: 10.37570/bgsd-2022-70-03
T. Waight, Mikael Stokholm, B. Heredia, T. Thomsen
A granitic sample from the Danish island of Christiansø in the Ertholmene island group north of Bornholm is described petrographically and geochemically, and dated using U-Pb in zircon and titanite. Zircon systematics in the sample are complicated by abundant Pb loss and a large population of zircons interpreted as being inherited. Removal of highly disturbed zircons, imprecise analyses, and assumed inherited zircons yield an upper intercept date of 1500 ± 18 Ma (MSWD = 13, n = 58). Removal of zircons with high common Pb from this population yields an identical result of 1500 ± 22 Ma (MSWD = 8, n = 34). Zircons that are ≤3% discordant give a weighted average 206Pb/238U age of 1458 ± 12 Ma (MSWD = 3.0, n = 18), and a weighted average 207Pb/206Pb age of 1495 ± 14 Ma (MSWD = 4.7, n = 19). Titanites from the sample yield a lower intercept age of 1448 ± 15 Ma (MSWD = 6.8, n = 45). The sample contains a significant number of inherited grains indicative of ages around 1.7–1.8 Ga. The relatively large MSWDs for these age determinations indicate geological complexity, likely reflecting Pb loss, and the possible presence of inherited zircons which suffered major Pb loss during incorporation in the granitic magma. The zircon and titanite dates agree reasonably well with previous age determinations on felsic lithologies from the Bornholm mainland, as well as from the Blekinge Province of southern Sweden. Petrographically and geochemically, the Christiansø granite is indistinguishable from, and can be correlated with, the A-type granites and gneisses which occur on Bornholm. The high abundance of disturbed and inherited zircons (c. 1.7–1.8 Ga) may indicate that the granite was intruded into and assimilated a nearby region of unexposed Transscandinavian Igneous Belt rocks. The somewhat altered nature of the rock, and overall disturbance of U-Pb zircon systematics, suggest alteration associated with fluid-flow along nearby faults defining the northern margin of the Sorgenfrei–Tornquist Zone.
{"title":"U-Pb zircon and titanite age of the Christiansø granite, Ertholmene, Denmark, and correlation with other Bornholm granitoids","authors":"T. Waight, Mikael Stokholm, B. Heredia, T. Thomsen","doi":"10.37570/bgsd-2022-70-03","DOIUrl":"https://doi.org/10.37570/bgsd-2022-70-03","url":null,"abstract":"A granitic sample from the Danish island of Christiansø in the Ertholmene island group north of Bornholm is described petrographically and geochemically, and dated using U-Pb in zircon and titanite. Zircon systematics in the sample are complicated by abundant Pb loss and a large population of zircons interpreted as being inherited. Removal of highly disturbed zircons, imprecise analyses, and assumed inherited zircons yield an upper intercept date of 1500 ± 18 Ma (MSWD = 13, n = 58). Removal of zircons with high common Pb from this population yields an identical result of 1500 ± 22 Ma (MSWD = 8, n = 34). Zircons that are ≤3% discordant give a weighted average 206Pb/238U age of 1458 ± 12 Ma (MSWD = 3.0, n = 18), and a weighted average 207Pb/206Pb age of 1495 ± 14 Ma (MSWD = 4.7, n = 19). Titanites from the sample yield a lower intercept age of 1448 ± 15 Ma (MSWD = 6.8, n = 45). The sample contains a significant number of inherited grains indicative of ages around 1.7–1.8 Ga. The relatively large MSWDs for these age determinations indicate geological complexity, likely reflecting Pb loss, and the possible presence of inherited zircons which suffered major Pb loss during incorporation in the granitic magma. The zircon and titanite dates agree reasonably well with previous age determinations on felsic lithologies from the Bornholm mainland, as well as from the Blekinge Province of southern Sweden. Petrographically and geochemically, the Christiansø granite is indistinguishable from, and can be correlated with, the A-type granites and gneisses which occur on Bornholm. The high abundance of disturbed and inherited zircons (c. 1.7–1.8 Ga) may indicate that the granite was intruded into and assimilated a nearby region of unexposed Transscandinavian Igneous Belt rocks. The somewhat altered nature of the rock, and overall disturbance of U-Pb zircon systematics, suggest alteration associated with fluid-flow along nearby faults defining the northern margin of the Sorgenfrei–Tornquist Zone.","PeriodicalId":55310,"journal":{"name":"Bulletin of the Geological Society of Denmark","volume":null,"pages":null},"PeriodicalIF":1.2,"publicationDate":"2022-03-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49535799","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 : 2022-03-03DOI: 10.37570/bgsd-2022-70-02
Iban Goñi, G. Cuny
Nine shark teeth were collected at Arnager in the south-western part of the island of Bornholm (Baltic Sea, Denmark). They all come from the basal conglomerate of the Coniacian (Upper Cretaceous) Arnager Limestone Formation and belong to the genus Ptychodus Agassiz, 1834. Three different species are dentified: P. altior, P. latissimus and P. mammillaris, which were hitherto unknown in Denmark.
{"title":"New record of the genus Ptychodus Agassiz, 1834, (Chondrichthyes, Elasmobranchii) from the Upper Cretaceous of Bornholm (Denmark)","authors":"Iban Goñi, G. Cuny","doi":"10.37570/bgsd-2022-70-02","DOIUrl":"https://doi.org/10.37570/bgsd-2022-70-02","url":null,"abstract":"Nine shark teeth were collected at Arnager in the south-western part of the island of Bornholm (Baltic Sea, Denmark). They all come from the basal conglomerate of the Coniacian (Upper Cretaceous) Arnager Limestone Formation and belong to the genus Ptychodus Agassiz, 1834. Three different species are dentified: P. altior, P. latissimus and P. mammillaris, which were hitherto unknown in Denmark.","PeriodicalId":55310,"journal":{"name":"Bulletin of the Geological Society of Denmark","volume":null,"pages":null},"PeriodicalIF":1.2,"publicationDate":"2022-03-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47732447","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 : 2022-01-30DOI: 10.37570/bgsd-2022-70-01
Thomas Holm, L. L. Delsett, P. Alsen
Vertebral centra are some of the most common fossils from ichthyosaurs and thus valuable for understanding these marine reptiles. This study sets out to provide further information on the dimensional ratios of centra and how these might be used to obtain more information about an assemblage of Late Jurassic disarticulated centra found at Kingofjeldet on Kuhn Ø in North-East Greenland in 2017. The centra are used to test whether vertebral ratios (H:W and H:L) can be used to assign disarticulated and possibly weathered centra to a region in the vertebral column. In order to evaluate this, the ratios of the centra from Greenland were compared with those of five articulated and well-known ophthalmosaurid specimens, as well as classical traits based on morphology. Assigning the correct position in the vertebral column from ratios is, however, not straightforward. Firstly, comparing different ichthyosaur taxa gives different possible positions for the disarticulated centra. Secondly, centra from different vertebral regions commonly display similar ratios. Thirdly, ratios are sensitive to alteration by taphonomic processes. The ratios of the centra hints towards an ichthyosaur with a more regionalised vertebral column being present in the Late Jurassic sea of North-East Greenland. Further studies are needed to improve our understanding of the significance of the degree of regionalisation of the vertebral column among ichthyosaurs.
{"title":"Vertebral size ratios and the ichthyosaurian vertebral column – a case study based on Late Jurassic fossils from North-East Greenland","authors":"Thomas Holm, L. L. Delsett, P. Alsen","doi":"10.37570/bgsd-2022-70-01","DOIUrl":"https://doi.org/10.37570/bgsd-2022-70-01","url":null,"abstract":"Vertebral centra are some of the most common fossils from ichthyosaurs and thus valuable for understanding these marine reptiles. This study sets out to provide further information on the dimensional ratios of centra and how these might be used to obtain more information about an assemblage of Late Jurassic disarticulated centra found at Kingofjeldet on Kuhn Ø in North-East Greenland in 2017. The centra are used to test whether vertebral ratios (H:W and H:L) can be used to assign disarticulated and possibly weathered centra to a region in the vertebral column. In order to evaluate this, the ratios of the centra from Greenland were compared with those of five articulated and well-known ophthalmosaurid specimens, as well as classical traits based on morphology. Assigning the correct position in the vertebral column from ratios is, however, not straightforward. Firstly, comparing different ichthyosaur taxa gives different possible positions for the disarticulated centra. Secondly, centra from different vertebral regions commonly display similar ratios. Thirdly, ratios are sensitive to alteration by taphonomic processes. The ratios of the centra hints towards an ichthyosaur with a more regionalised vertebral column being present in the Late Jurassic sea of North-East Greenland. Further studies are needed to improve our understanding of the significance of the degree of regionalisation of the vertebral column among ichthyosaurs.","PeriodicalId":55310,"journal":{"name":"Bulletin of the Geological Society of Denmark","volume":null,"pages":null},"PeriodicalIF":1.2,"publicationDate":"2022-01-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44015988","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 : 2021-12-18DOI: 10.37570/bgsd-2021-69-09
Kai Ingemann Schnetler, Mogens Stentoft Nielsen
The predominantly Cretaceous gastropod genus Vanikoropsis Meek, 1876 is represented in the Paleocene of Denmark and West Greenland by four species, of which three are established herein as new, viz. Vanikoropsis mortenseni n. sp., Vanikoropsis (s.l.) jakobseni n. sp. and Vanikoropsis (s.l.) bashforthi n. sp. The Danish species was found in a boulder of Kerteminde Marl (Selandian, middle Paleocene) from Gundstrup, while the species from West Greenland were found in the localities Sonja Lens and Qaarsutjægerdal on the Nuussuaq peninsula (late Danian, early Paleocene). The Danish species extends the stratigraphic range of the genus into the middle Paleocene and supports the affinities of the Kerteminde Marl fauna to the Paleocene fauna of West Greenland.
{"title":"On the genus Vanikoropsis Meek, 1876 (Gastropoda, Caenogastropoda) from the Paleocene of Denmark and West Greenland with descriptions of three new species","authors":"Kai Ingemann Schnetler, Mogens Stentoft Nielsen","doi":"10.37570/bgsd-2021-69-09","DOIUrl":"https://doi.org/10.37570/bgsd-2021-69-09","url":null,"abstract":"The predominantly Cretaceous gastropod genus Vanikoropsis Meek, 1876 is represented in the Paleocene of Denmark and West Greenland by four species, of which three are established herein as new, viz. Vanikoropsis mortenseni n. sp., Vanikoropsis (s.l.) jakobseni n. sp. and Vanikoropsis (s.l.) bashforthi n. sp. The Danish species was found in a boulder of Kerteminde Marl (Selandian, middle Paleocene) from Gundstrup, while the species from West Greenland were found in the localities Sonja Lens and Qaarsutjægerdal on the Nuussuaq peninsula (late Danian, early Paleocene). The Danish species extends the stratigraphic range of the genus into the middle\u0000Paleocene and supports the affinities of the Kerteminde Marl fauna to the Paleocene fauna of West Greenland.","PeriodicalId":55310,"journal":{"name":"Bulletin of the Geological Society of Denmark","volume":null,"pages":null},"PeriodicalIF":1.2,"publicationDate":"2021-12-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44143172","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 : 2021-12-18DOI: 10.37570/bgsd-2021-69-10
A. Rosenkrantz, F. Surlyk, K. Anderskouv, P. Frykman, L. Stemmerik, N. Thibault
A 460 m long profile of the Cretaceous–Paleogene (K–T) boundary strata at Stevns Klint was measured by the late Professor A. Rosenkrantz probably in 1944. The measured profile was inherited by Finn Surlyk around 1974 together with other original boundary data. This material was dug up in a long-forgotten drawer in connection with detailed field work by the co-authors on the boundary succession in the late spring and summer of 2021. The profile illustrates the stratigraphy, geometry and palaeotopography of the boundary strata in unprecedented detail. The part of the cliff illustrated in the profile is today partly covered by beach ridges composed of flint rubble but is situated below the finest section of the lower Danian bryozoan mounds exposed at Stevns Klint. This coastal section is situated immediately adjacent to a large limestone quarry and was planned to be quarried away around 1937, but was saved by A. Rosenkrantz who demonstrated its great scientific and educational value to the authorities.
{"title":"The K–T boundary strata north of Korsnæb, Stevns Klint, Denmark – evolution and geometry revealed in a long, horizontal profile","authors":"A. Rosenkrantz, F. Surlyk, K. Anderskouv, P. Frykman, L. Stemmerik, N. Thibault","doi":"10.37570/bgsd-2021-69-10","DOIUrl":"https://doi.org/10.37570/bgsd-2021-69-10","url":null,"abstract":"A 460 m long profile of the Cretaceous–Paleogene (K–T) boundary strata at Stevns Klint was measured by the late Professor A. Rosenkrantz probably in 1944. The measured profile was inherited by Finn Surlyk around 1974 together with other original boundary data. This material was dug up in a long-forgotten drawer in connection\u0000with detailed field work by the co-authors on the boundary succession in the late spring and summer of 2021. The profile illustrates the stratigraphy, geometry and palaeotopography of the boundary strata in unprecedented detail. The part of the cliff illustrated in the profile is today partly covered by beach ridges composed of flint rubble but is situated below the finest section of the lower Danian bryozoan mounds exposed at Stevns Klint. This coastal section is situated immediately adjacent to a large limestone quarry and was planned to be quarried away around 1937, but was saved by A. Rosenkrantz who demonstrated its great scientific and educational value to the authorities.","PeriodicalId":55310,"journal":{"name":"Bulletin of the Geological Society of Denmark","volume":null,"pages":null},"PeriodicalIF":1.2,"publicationDate":"2021-12-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42946834","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}
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