Pub Date : 2018-07-04DOI: 10.37570/bgsd-2018-66-06
M. Erlström, Lars-Ole Booldreel, S. Lindström, Morten Andersen, L. Kristensen, A. Mathiesen, Elina Kamla, L. Nielsen
The Øresund Basin in the transnational area between Sweden and Denmark forms a marginal part of the Danish Basin. The structural outline and stratigraphy of the Mesozoic succession is described, and a novel interpretation and description of the subsurface geology and geothermal potential in the North Sjælland Half-graben is presented. The subsurface bedrock in the basin includes several Mesozoic intervals with potential geothermal sandstone reservoirs. Parts of the succession fulfill specific geological requirements with regard to distribution, composition and quality of the sandstones. A characterisation of these is presently of great interest in the attempt to identify geothermal reservoirs suitable for district heating purposes. The results presented in this paper include for the first time a comprehensive description of the stratigraphic intervals as well as the characteristics of the potential Mesozoic geothermal reservoirs in the Øresund region, including their distribution, composition and physical properties. This is illustrated by seismic cross-sections and well sections. In addition, results from analyses and evaluations of porosity, permeability, formation fluids and temperature are presented. Six potential geothermal reservoirs in the Mesozoic succession are described and assessed. Primary focus is placed on the characteristics of the reservoirs in the Lower Triassic and Rhaetian–Lower Jurassic succession. The study shows that the Mesozoic reservoir sandstones vary considerably with respect to porosity and permeability. Values range between 5–25% for the pre-Rhaetian Triassic sandstones and are commonly >25% for the Rhaetian–Lower Jurassic and Lower Cretaceous sandstones. The corresponding permeability rarely reaches 500 mD for the pre-Rhaetian Triassic reservoirs, while it is commonly above one Darcy for the Rhaetian–Lower Jurassic and the Lower Cretaceous sandstones. The interpreted formation temperatures are 45–50°C at 1500 m, 60–70°C at 2000 m and 70–90°C at 2500 m depth. The combined results provide a geological framework for making site-specific predictions regarding appraisal of viable geothermal projects for district heating purposes in the region as well as reducing the risk of unsuccessful wells.
{"title":"Stratigraphy and geothermal assessment of Mesozoic sandstone reservoirs in the Øresund Basin – exemplified by well data and seismic profiles","authors":"M. Erlström, Lars-Ole Booldreel, S. Lindström, Morten Andersen, L. Kristensen, A. Mathiesen, Elina Kamla, L. Nielsen","doi":"10.37570/bgsd-2018-66-06","DOIUrl":"https://doi.org/10.37570/bgsd-2018-66-06","url":null,"abstract":"The Øresund Basin in the transnational area between Sweden and Denmark forms a marginal part of the Danish Basin. The structural outline and stratigraphy of the Mesozoic succession is described, and a novel interpretation and description of the subsurface geology and geothermal potential in the North Sjælland Half-graben is presented. The subsurface bedrock in the basin includes several Mesozoic intervals with potential geothermal sandstone reservoirs. Parts of the succession fulfill specific\u0000geological requirements with regard to distribution, composition and quality of the sandstones. A characterisation of these is presently of great interest in the attempt to identify geothermal reservoirs suitable for district heating purposes. The results presented in this paper include for the first time a comprehensive description of the stratigraphic intervals as well as the characteristics of the potential Mesozoic geothermal reservoirs in the Øresund region, including their distribution, composition and physical properties. This is illustrated by seismic cross-sections and well sections. In addition, results from analyses and evaluations of porosity, permeability, formation fluids and temperature are presented. Six potential geothermal reservoirs in the Mesozoic succession are described and assessed. Primary focus is placed on the characteristics of the reservoirs in the Lower Triassic and Rhaetian–Lower Jurassic succession. The study shows that the Mesozoic reservoir sandstones vary considerably with respect to porosity and permeability. Values range between 5–25% for the pre-Rhaetian Triassic sandstones and are commonly >25% for the Rhaetian–Lower Jurassic and Lower Cretaceous sandstones. The corresponding permeability rarely reaches 500 mD for the pre-Rhaetian Triassic reservoirs, while it is commonly above one Darcy for the Rhaetian–Lower Jurassic and the Lower Cretaceous sandstones. The interpreted formation temperatures are 45–50°C at 1500 m, 60–70°C at 2000 m and 70–90°C at 2500 m depth. The combined results provide a geological framework for making site-specific predictions regarding appraisal of viable geothermal projects for district heating purposes in the region as well as reducing the risk of unsuccessful wells.","PeriodicalId":55310,"journal":{"name":"Bulletin of the Geological Society of Denmark","volume":" ","pages":""},"PeriodicalIF":1.2,"publicationDate":"2018-07-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45971443","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 : 2018-06-29DOI: 10.37570/bgsd-2018-66-05
O. Bennike, M. Mortensen
During the early part of the Allerød period, from c. 13 600 to 13 330 years BP, unstable soils with a tundra-like open, treeless vegetation with Betula nana and Dryas octopetala were found around Søndre Kobberdam in Hareskovene. Open Betula pubescens woodland was not established until the middle Allerød about 13 330 years BP. During the Younger Dryas, Betula nana and Dryas octopetala spread again, and Betula pubescens almost disappeared. From the onset of the Holocene warming an open tundra landscape characterised the area. About 11 300 years BP Betula pubescens started to recolonise the region and Populus tremula and Pinus sylvetris arrived at c. 11 000 years BP, replacing the open landscape by woodland. Along the margin of the lake Carex paniculata, Carex riparia and Cladium mariscus were growing. The lake fauna included a rich and diverse fauna of molluscs that thrived in the carbonate-rich waters. We did not find any evidence for the local presence of Pinus sylvestris during the late glacial.
{"title":"A multi-disciplinary macrofossil study of late glacial to early Holocene sediments from Søndre Kobberdam, Hareskovene, Denmark","authors":"O. Bennike, M. Mortensen","doi":"10.37570/bgsd-2018-66-05","DOIUrl":"https://doi.org/10.37570/bgsd-2018-66-05","url":null,"abstract":"During the early part of the Allerød period, from c. 13 600 to 13 330 years BP, unstable soils with a tundra-like open, treeless vegetation with Betula nana and Dryas octopetala were found around Søndre Kobberdam in Hareskovene. Open Betula pubescens woodland was not established until the middle Allerød about 13 330 years BP. During the Younger Dryas, Betula nana and Dryas octopetala spread again, and Betula pubescens almost disappeared. From the onset of the Holocene warming an open tundra landscape characterised the area. About 11 300 years BP Betula pubescens started to recolonise the region and Populus tremula and Pinus sylvetris arrived at c. 11 000 years BP, replacing the open landscape by woodland. Along the margin of the lake Carex paniculata, Carex riparia and Cladium mariscus were growing. The lake fauna included a rich and diverse fauna of molluscs that thrived in the carbonate-rich waters. We did not find any evidence for the local presence of Pinus sylvestris during the late glacial.","PeriodicalId":55310,"journal":{"name":"Bulletin of the Geological Society of Denmark","volume":"26 9","pages":""},"PeriodicalIF":1.2,"publicationDate":"2018-06-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41298192","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 : 2018-06-18DOI: 10.37570/bgsd-2018-66-04
J. Hovikoski, G. Pedersen, P. Alsen, K. Svennevig, H. N. Hansen, E. Sheldon, K. Dybkjær, J. Koefoed, M. Bjerager, J. Ineson, B. Lauridsen, S. Piasecki
Kilen, Kronprins Christian Land, contains the thickest and stratigraphically most complete Jurassic and Cretaceous sediment succession in North Greenland. This study revises and formalises the lithostratigraphic framework of these deposits. The work is based on recent extensive stratigraphic field work supplemented by photogeological mapping and biostratigraphic studies, and builds on the earlier stratigraphic work conducted mainly in the 1980s and 1990s. According to the new stratigraphic scheme, the more than 500 m thick Jurassic succession is divided into four formations. The poorly dated Gletscherport Formation comprises lagoonal heterolithic sandstones. The Mågensfjeld and Birkelund Fjeld Formations consist of shallow marine fine-grained sandstones of Bajocian–Bathonian and Kimmeridgian age, respectively. The Kuglelejet Formation comprises mainly shallow marine sandy mudstone and sandstone of Volgian age and includes the mudstone-dominated Splitbæk Member. The Lower Cretaceous interval is estimated to be more than 1500 m thick and is divided into three formations. The Dromledome Formation comprises deep shelf to offshore transition, black mudstones of late Ryazanian to Hauterivian age. It is erosively overlain by unfossiliferous, fluvial and estuarine sandstones of the Lichenryg Formation. The overlying, late Aptian to middle Cenomanian Galadriel Fjeld Formation comprises six members, of which the Tågekyst and Kangoq Ryg Members occur in the Gåseslette area, whereas the Pil, Valmue, Stenbræk and Hondal Members occur in the Kilen Fjelde area. The Galadriel Fjeld Formation is characterised by interbedded mudstones and sandstones from offshore–shoreface environments. The 650 m thick Upper Cretaceous succession is assigned to the Sølverbæk Formation, which is undivided in the Gåseslette area and divided into the Skalbæk and Scaphitesnæse Members in the Kilen Fjelde area. The Sølverbæk Formation is dominated by marine mudstones and sandstonemudstone heteroliths of late Cenomanian to Santonian age. The new lithostratigraphic framework and significant biostratigraphic advances allow a closer correlation of the Mesozoic units between North Greenland and other Arctic basins.
{"title":"The Jurassic–Cretaceous lithostratigraphy of Kilen, Kronprins Christian Land, eastern North Greenland","authors":"J. Hovikoski, G. Pedersen, P. Alsen, K. Svennevig, H. N. Hansen, E. Sheldon, K. Dybkjær, J. Koefoed, M. Bjerager, J. Ineson, B. Lauridsen, S. Piasecki","doi":"10.37570/bgsd-2018-66-04","DOIUrl":"https://doi.org/10.37570/bgsd-2018-66-04","url":null,"abstract":"Kilen, Kronprins Christian Land, contains the thickest and stratigraphically most complete Jurassic and Cretaceous sediment succession in North Greenland. This study revises and formalises the lithostratigraphic framework of these deposits. The work is based on recent extensive stratigraphic field work supplemented by photogeological mapping and biostratigraphic studies, and builds on the earlier stratigraphic work conducted mainly in the 1980s and 1990s. According to the new stratigraphic scheme, the more than 500 m thick Jurassic succession is divided into four formations. The poorly dated Gletscherport Formation comprises lagoonal heterolithic sandstones. The Mågensfjeld and Birkelund Fjeld Formations consist of shallow marine fine-grained sandstones of Bajocian–Bathonian and Kimmeridgian age, respectively. The Kuglelejet Formation comprises mainly shallow marine sandy mudstone and sandstone of Volgian age and includes the mudstone-dominated Splitbæk Member. The Lower Cretaceous interval is estimated to be more than 1500 m thick and is divided into three formations. The Dromledome Formation comprises deep shelf to offshore transition, black mudstones of late Ryazanian to Hauterivian age. It is erosively overlain by unfossiliferous, fluvial and estuarine sandstones of the Lichenryg Formation. The overlying, late Aptian to middle Cenomanian Galadriel Fjeld Formation comprises six members, of which the Tågekyst and Kangoq Ryg Members occur in the Gåseslette area, whereas the Pil, Valmue, Stenbræk and Hondal Members occur in the Kilen Fjelde area. The Galadriel Fjeld Formation is characterised by interbedded mudstones and sandstones from offshore–shoreface environments. The 650 m thick Upper Cretaceous succession is assigned to the Sølverbæk Formation, which is undivided in the Gåseslette area and divided into the Skalbæk and Scaphitesnæse Members in the Kilen Fjelde area. The Sølverbæk Formation is dominated by marine mudstones and sandstonemudstone heteroliths of late Cenomanian to Santonian age. The new lithostratigraphic framework and significant biostratigraphic advances allow a closer correlation of the Mesozoic units between North Greenland and other Arctic basins.","PeriodicalId":55310,"journal":{"name":"Bulletin of the Geological Society of Denmark","volume":" ","pages":""},"PeriodicalIF":1.2,"publicationDate":"2018-06-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45091148","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 : 2018-06-03DOI: 10.37570/bgsd-2018-66-03
G. Cuny, L. Stemmerik
The Moscovian of eastern North Greenland has yielded an assemblage dominated by teeth and dermal denticles of chondrichthyans with rarer teeth of actinopterygians. The rather poor preservation of the material precludes precise identification but the following taxa have been recorded: Adamantina foliacea, Bransonella spp., Denaea sp., “Stemmatias” simplex, Lagarodus specularis, Actinopterygii indet., as well as teeth probably belonging to new genera of Heslerodidae, ?Protacrodontidae and Hybodontiformes. This fauna appears therefore quite endemic. The abundance of Bransonella and durophagous chondrichthyans is in accordance with the shallow marine depositional environment. The record of a ?protacrodontid is possibly the youngest one for this taxon.
{"title":"New fossil fish microremains from the Upper Carboniferous of eastern North Greenland.","authors":"G. Cuny, L. Stemmerik","doi":"10.37570/bgsd-2018-66-03","DOIUrl":"https://doi.org/10.37570/bgsd-2018-66-03","url":null,"abstract":"The Moscovian of eastern North Greenland has yielded an assemblage dominated by teeth and dermal denticles of chondrichthyans with rarer teeth of actinopterygians. The rather poor preservation of the material precludes precise identification but the following taxa have been recorded: Adamantina foliacea, Bransonella spp., Denaea sp., “Stemmatias” simplex, Lagarodus specularis, Actinopterygii indet., as well as teeth probably belonging to new genera of Heslerodidae, ?Protacrodontidae and Hybodontiformes. This fauna appears therefore quite endemic. The abundance of Bransonella and durophagous chondrichthyans is in accordance with the shallow marine depositional environment. The record of a ?protacrodontid is possibly the youngest one for this taxon.","PeriodicalId":55310,"journal":{"name":"Bulletin of the Geological Society of Denmark","volume":" ","pages":""},"PeriodicalIF":1.2,"publicationDate":"2018-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43860710","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 : 2018-03-03DOI: 10.37570/BGSD-2018-66-02
M. Marzola, O. Mateus, J. Milán, L. Clemmensen
This article presents a synthesis of Palaeozoic and Mesozoic fossil tetrapods from Greenland, including an updated review of the holotypes and a new photographic record of the main specimens. All fossil tetrapods found are from East Greenland, with at least 30 different known taxa: five stem tetrapods (Acanthostega gunnari, Ichthyostega eigili, I. stensioi, I. watsoni, and Ymeria denticulata) from the Late Devonian of the Aina Dal and Britta Dal Formations; four temnospondyl amphibians (Aquiloniferus kochi, Selenocara groenlandica, Stoschiosaurus nielseni, and Tupilakosaurus heilmani) from the Early Triassic of the Wordie Creek Group; two temnospondyls (Cyclotosaurus naraserluki and Gerrothorax cf. pulcherrimus), one testudinatan (cf. Proganochelys), two stagonolepids (Aetosaurus ferratus and Paratypothorax andressorum), the eudimorphodontid Arcticodactylus, undetermined archosaurs (phytosaurs and both sauropodomorph and theropod dinosaurs), the cynodont Mitredon cromptoni, and three mammals (Haramiyavia clemmenseni, Kuehneotherium, and cf. ?Brachyzostrodon), from the Late Triassic of the Fleming Fjord Formation; one plesiosaur from the Early Jurassic of the Kap Stewart Formation; one plesiosaur and one ichthyosaur from the Late Jurassic of the Kap Leslie Formation, plus a previously unreported Late Jurassic plesiosaur from Kronprins Christian Land. Moreover, fossil tetrapod trackways are known from the Late Carboniferous (morphotype Limnopus) of the Mesters Vig Formation and at least four different morphologies (such as the crocodylomorph Brachychirotherium, the sauropodomorph Eosauropus and Evazoum, and the theropodian Grallator) associated to archosaurian trackmakers are known from the Late Triassic of the Fleming Fjord Formation. The presence of rich fossiliferous tetrapod sites in East Greenland is linked to the presence of well-exposed continental and shallow marine deposits with most finds in terrestrial deposits from the Late Devonian and the Late Triassic.
{"title":"A review of Palaeozoic and Mesozoic tetrapods from Greenland","authors":"M. Marzola, O. Mateus, J. Milán, L. Clemmensen","doi":"10.37570/BGSD-2018-66-02","DOIUrl":"https://doi.org/10.37570/BGSD-2018-66-02","url":null,"abstract":"This article presents a synthesis of Palaeozoic and Mesozoic fossil tetrapods from Greenland, including an updated review of the holotypes and a new photographic record of the main specimens. All fossil tetrapods found are from East Greenland, with at least 30 different known taxa: five stem tetrapods (Acanthostega gunnari, Ichthyostega eigili, I. stensioi, I. watsoni, and Ymeria denticulata) from the Late Devonian of the Aina Dal and Britta Dal Formations; four temnospondyl amphibians (Aquiloniferus kochi, Selenocara groenlandica, Stoschiosaurus nielseni, and Tupilakosaurus heilmani) from the Early Triassic of the Wordie Creek Group; two temnospondyls (Cyclotosaurus naraserluki and Gerrothorax cf. pulcherrimus), one testudinatan (cf. Proganochelys), two stagonolepids (Aetosaurus ferratus and Paratypothorax andressorum), the eudimorphodontid Arcticodactylus, undetermined archosaurs (phytosaurs and both sauropodomorph and theropod dinosaurs), the cynodont Mitredon cromptoni, and three mammals (Haramiyavia clemmenseni, Kuehneotherium, and cf. ?Brachyzostrodon), from the Late Triassic of the Fleming Fjord Formation; one plesiosaur from the Early Jurassic of the Kap Stewart Formation; one plesiosaur and one ichthyosaur from the Late Jurassic of the Kap Leslie Formation, plus a previously unreported Late Jurassic plesiosaur from Kronprins Christian Land. Moreover, fossil tetrapod trackways are known from the Late Carboniferous (morphotype Limnopus) of the Mesters Vig Formation and at least four different morphologies (such as the crocodylomorph Brachychirotherium, the sauropodomorph Eosauropus and Evazoum, and the theropodian Grallator) associated to archosaurian trackmakers are known from the Late Triassic of the Fleming Fjord Formation. The presence of rich fossiliferous tetrapod sites in East Greenland is linked to the presence of well-exposed continental and shallow marine deposits with most finds in terrestrial deposits from the Late Devonian and the Late Triassic.","PeriodicalId":55310,"journal":{"name":"Bulletin of the Geological Society of Denmark","volume":"66 1","pages":"21-46"},"PeriodicalIF":1.2,"publicationDate":"2018-03-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43037746","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 : 2018-02-02DOI: 10.37570/bgsd-2018-66-01
N. Schovsbo, A. T. Nielsen, A. O. Harstad, D. Bruton
The fully cored BHD-03-99 borehole (hereafter referred to as the Porsgrunn borehole and core) penetrated Ordovician and Cambrian strata in the Skien–Langesund district, southern part of the Oslo region in Norway. Hand-held X-ray fluorescence (HH-XRF) measurements combined with spectral gamma ray and density core scanning of the Middle Cambrian – Furongian Alum Shale Formation have been made and compared with similar measurements obtained on Alum Shale cores from Scania (southernmost Sweden) and Bornholm (Denmark). The Porsgrunn drill site is located in an area that was only mildly overprinted by Caledonian tectonics and represents one of the few sites in the Oslo area where a nearly untectonised sedimentary succession can be studied in terms of thickness and geochemistry. The Alum Shale Formation is 28.8 m thick in the Porsgrunn core, excluding the thickness of five 0.9–5.5 m thick dolerite sills of assumed Permian age. In the Alum Shale Formation the bulk densities are around 2.7 g/cm3 with a slightly decreasing trend up through the formation. The shale has total organic carbon (TOC) values up to 14 wt%, which is comparable to the TOC levels for the Alum Shale elsewhere in the Oslo area and for dry gas matured Alum Shale in Scania and Bornholm. The basal Furongian is characterised by a gamma ray low and an increase in Mo interpreted to reflect the Steptoean Positive Carbon Isotope Excursion (SPICE) event. The Porsgrunn core data suggest that the Mo concentration remained high also after the SPICE event. Characteristic, readily identified features in the gamma log motif are named the Andrarum gamma low (AGL), base Furongian gamma low (BFGL), Olenus triple gamma spike (OTGS) and the Peltura gamma spike (PGS). No Lower Ordovician Alum Shale is present. The 14.8 m thick Furongian part of the Alum Shale represents the Olenus, Parabolina, Leptoplastus, Protopeltura and Peltura trilobite superzones judging from log-stratigraphic correlations to Scania and Bornholm. The Middle Cambrian interval is 14.0 m thick and includes the Exsulans Limestone Bed and 1.4 m of quartz sandstone. A 0.3 m thick primary limestone bed may be an equivalent to the Andrarum Limestone Bed. The succession represents the Paradoxides paradoxissimus and P. forchhammeri superzones. The Alum Shale Formation rests atop the 13.0 m thick Lower Cambrian Stokkevannet sandstone (new informal name) that in turn directly overlies the basement. Overall, the stratigraphic development of the comparatively thin Alum Shale Formation resembles the condensed sequence seen on Bornholm.
{"title":"Stratigraphy and geochemical composition of the Cambrian Alum Shale Formation in the Porsgrunn core, Skien–Langesund district, southern Norway.","authors":"N. Schovsbo, A. T. Nielsen, A. O. Harstad, D. Bruton","doi":"10.37570/bgsd-2018-66-01","DOIUrl":"https://doi.org/10.37570/bgsd-2018-66-01","url":null,"abstract":"The fully cored BHD-03-99 borehole (hereafter referred to as the Porsgrunn borehole and core) penetrated Ordovician and Cambrian strata in the Skien–Langesund district, southern part of the Oslo region in Norway. Hand-held X-ray fluorescence (HH-XRF) measurements combined with spectral gamma ray and density core scanning of the Middle Cambrian – Furongian Alum Shale Formation have been made and compared with similar measurements obtained on Alum Shale cores from Scania (southernmost Sweden) and Bornholm (Denmark). The Porsgrunn drill site is located in an area that was only mildly overprinted by Caledonian tectonics and represents one of the few sites in the Oslo area where a nearly untectonised sedimentary succession can be studied in terms of thickness and geochemistry. The Alum Shale Formation is 28.8 m thick in the Porsgrunn core, excluding the thickness of five 0.9–5.5 m thick dolerite sills of assumed Permian age. In the Alum Shale Formation the bulk densities are around 2.7 g/cm3 with a slightly decreasing trend up through the formation. The shale has total organic carbon (TOC) values up to 14 wt%, which is comparable to the TOC levels for the Alum Shale elsewhere in the Oslo area and for dry gas matured Alum Shale in Scania and Bornholm. The basal Furongian is characterised by a gamma ray low and an increase in Mo interpreted to reflect the Steptoean Positive Carbon Isotope Excursion (SPICE) event. The Porsgrunn core data suggest that the Mo concentration remained high also after the SPICE event. Characteristic, readily identified features in the gamma log motif are named the Andrarum gamma low (AGL), base Furongian gamma low (BFGL), Olenus triple gamma spike (OTGS) and the Peltura gamma spike (PGS). No Lower Ordovician Alum Shale is present. The 14.8 m thick Furongian part of the Alum Shale represents the Olenus, Parabolina, Leptoplastus, Protopeltura and Peltura trilobite superzones judging from log-stratigraphic correlations to Scania and Bornholm. The Middle Cambrian interval is 14.0 m thick and includes the Exsulans Limestone Bed and 1.4 m of quartz sandstone. A 0.3 m thick primary limestone bed may be an equivalent to the Andrarum Limestone Bed. The succession represents the Paradoxides paradoxissimus and P. forchhammeri superzones. The Alum Shale Formation rests atop the 13.0 m thick Lower Cambrian Stokkevannet sandstone (new informal name) that in turn directly overlies the basement. Overall, the stratigraphic development of the comparatively thin Alum Shale Formation resembles the condensed sequence seen on Bornholm.","PeriodicalId":55310,"journal":{"name":"Bulletin of the Geological Society of Denmark","volume":"66 1","pages":"1-20"},"PeriodicalIF":1.2,"publicationDate":"2018-02-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49566924","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 : 2017-11-14DOI: 10.37570/bgsd-2017-65-10
C. Duffin, J. Milán
A new myriacanthid holocephalian is described from the Hasle Formation (probably the Uptonia jamesoni subzone to the Acanthopleuroceras valdani subzone, Early Pliensbachian, Early Jurassic) of Bornholm, Denmark, on the basis of isolated upper posterior (palatine) and lower posterior (mandibular) tooth plates. Oblidens bornholmensis gen. et sp. nov. differs from all other myriacanthids for which the same dental elements are known, in the distribution of the hypermineralised tissue covering the occlusal surfaces of the tooth plates, and the arrangement of the ridges transecting the tooth plate surface and so varying their surface relief. Oblidens is the first myriacanthid holocephalian to be recorded both from the Pliensbachian and from Denmark. The presence of a further, undetermined myriacanthid tooth plate is noted from the same locality.
{"title":"A new myriacanthid holocephalian from the Early Jurassic of Denmark.","authors":"C. Duffin, J. Milán","doi":"10.37570/bgsd-2017-65-10","DOIUrl":"https://doi.org/10.37570/bgsd-2017-65-10","url":null,"abstract":"A new myriacanthid holocephalian is described from the Hasle Formation (probably the Uptonia jamesoni subzone to the Acanthopleuroceras valdani subzone, Early Pliensbachian, Early Jurassic) of Bornholm, Denmark, on the basis of isolated upper posterior (palatine) and lower posterior (mandibular) tooth plates. Oblidens bornholmensis gen. et sp. nov. differs from all other myriacanthids for which the same dental elements are known, in the distribution of the hypermineralised tissue covering the occlusal surfaces of the tooth plates, and the arrangement of the ridges transecting the tooth plate surface and so varying their surface relief. Oblidens is the first myriacanthid holocephalian to be recorded both from the Pliensbachian and from Denmark. The presence of a further, undetermined myriacanthid tooth plate is noted from the same locality.","PeriodicalId":55310,"journal":{"name":"Bulletin of the Geological Society of Denmark","volume":"65 1","pages":"161-170"},"PeriodicalIF":1.2,"publicationDate":"2017-11-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45661736","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 : 2017-10-31DOI: 10.37570/bgsd-2017-65-09
D. K. Loydell, N. Walasek, N. Schovsbo, A. T. Nielsen
The Sommerodde-1 core provides a continuous record through the subsurface of southern Bornholm from the Wenlock Series (Silurian) through to the Lower Cambrian. The Silurian graptolite biostratigraphy of the core is described. For the Rhuddanian and Aeronian (lower and middle Llandovery), the succession and thickness of biozones are very similar to those in the Øleå rivulet nearby. For the upper Llandovery, the lower Telychian Spirograptus guerichi and Sp. turriculatus biozones are significantly thicker in the core than in Øleå, whilst the uppermost Telychian (represented by more than 30 m of strata in nearby sections) is largely absent in the core. This is likely to be a reflection of synsedimentary faulting influencing deposition. It has previously been suggested that much of the Sheinwoodian is missing on Bornholm; this is not the case. The Sheinwoodian is represented by an apparently continuous sequence, at least 31 m thick, in the Sommerodde-1 core.
{"title":"Graptolite biostratigraphy of the lower Silurian of the Sommerodde-1 core, Bornholm, Denmark","authors":"D. K. Loydell, N. Walasek, N. Schovsbo, A. T. Nielsen","doi":"10.37570/bgsd-2017-65-09","DOIUrl":"https://doi.org/10.37570/bgsd-2017-65-09","url":null,"abstract":"The Sommerodde-1 core provides a continuous record through the subsurface of southern Bornholm from the Wenlock Series (Silurian) through to the Lower Cambrian. The Silurian graptolite biostratigraphy of the core is described. For the Rhuddanian and Aeronian (lower and middle Llandovery), the succession and thickness of biozones are very similar to those in the Øleå rivulet nearby. For the upper Llandovery, the lower Telychian Spirograptus guerichi and Sp. turriculatus biozones are significantly thicker in the core than in Øleå, whilst the uppermost Telychian (represented by more than 30 m of strata in nearby sections) is largely absent in the core. This is likely to be a reflection of synsedimentary faulting influencing deposition. It has previously been suggested that much of the Sheinwoodian is missing on Bornholm; this is not the case. The Sheinwoodian is represented by an apparently continuous sequence, at least 31 m thick, in the Sommerodde-1 core.","PeriodicalId":55310,"journal":{"name":"Bulletin of the Geological Society of Denmark","volume":"65 1","pages":"135-160"},"PeriodicalIF":1.2,"publicationDate":"2017-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42941328","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 : 2017-09-25DOI: 10.37570/bgsd-2017-65-07
F. Surlyk, M. Bjerager, S. Piasecki, L. Stemmerik
{"title":"Stratigraphy of the marine Lower Triassic succession at Kap Stosch, Hold with Hope, North-East Greenland","authors":"F. Surlyk, M. Bjerager, S. Piasecki, L. Stemmerik","doi":"10.37570/bgsd-2017-65-07","DOIUrl":"https://doi.org/10.37570/bgsd-2017-65-07","url":null,"abstract":"","PeriodicalId":55310,"journal":{"name":"Bulletin of the Geological Society of Denmark","volume":"65 1","pages":"87-123"},"PeriodicalIF":1.2,"publicationDate":"2017-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48794779","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 : 2017-02-15DOI: 10.37570/BGSD-2017-65-01
J. Adolfssen, J. Milán, M. Friedman
The vertebrate fauna in the Danian deposits of Denmark and southern Sweden is reviewed. Remains of sharks and bony fishes are widely distributed but not common in the Danian limestones, with the exception of the K/Pg-boundary clay, the Fiskeler Member, at the UNESCO World Heritage Site Stevns Klint, which can include substantial quantities of shark teeth and fragments of bony fishes. Articulated remains of bony fishes are known from the Fiskeler Member at Stevns Klint and the København Limestone Formation in the Limhamn quarry. Sharks are only found as isolated teeth and rare isolated vertebrae. The gavialoid crocodylian Thoracosaurus is represented by a complete skull and associated postcranial material and an additional jaw fragment from the Limhamn quarry. Remains of a crocodylian skull, a cervical vertebra, a limb bone and isolated teeth have been found in the Faxe quarry, and a single possibly alligatorid tooth is known from the basal conglomerate of the Lellinge Greensand Formation from now closed exposures below Copenhagen. Fragmentary turtle material has been found in the Faxe and Limhamn quarries and in the København Limestone in Copenhagen, and bird remains are exclusively known from the Limhamn quarry. Despite the fragmentary nature of many of the finds, the total picture of the vertebrate fauna of southern Scandinavia is quite diverse comprising four classes, 23 orders, 41 families and 54 identifiable genera of which most can be identified to species level.
{"title":"Review of the danian vertebrate fauna of southern Scandinavia","authors":"J. Adolfssen, J. Milán, M. Friedman","doi":"10.37570/BGSD-2017-65-01","DOIUrl":"https://doi.org/10.37570/BGSD-2017-65-01","url":null,"abstract":"The vertebrate fauna in the Danian deposits of Denmark and southern Sweden is reviewed. Remains of sharks and bony fishes are widely distributed but not common in the Danian limestones, with the exception of the K/Pg-boundary clay, the Fiskeler Member, at the UNESCO World Heritage Site Stevns Klint, which can include substantial quantities of shark teeth and fragments of bony fishes. Articulated remains of bony fishes are known from the Fiskeler Member at Stevns Klint and the København Limestone Formation in the Limhamn quarry. Sharks are only found as isolated teeth and rare isolated vertebrae. The gavialoid crocodylian Thoracosaurus is represented by a complete skull and associated postcranial material and an additional jaw fragment from the Limhamn quarry. Remains of a crocodylian skull, a cervical vertebra, a limb bone and isolated teeth have been found in the Faxe quarry, and a single possibly alligatorid tooth is known from the basal conglomerate of the Lellinge Greensand Formation from now closed exposures below Copenhagen. Fragmentary turtle material has been found in the Faxe and Limhamn quarries and in the København Limestone in Copenhagen, and bird remains are exclusively known from the Limhamn quarry. Despite the fragmentary nature of many of the finds, the total picture of the vertebrate fauna of southern Scandinavia is quite diverse comprising four classes, 23 orders, 41 families and 54 identifiable genera of which most can be identified to species level.","PeriodicalId":55310,"journal":{"name":"Bulletin of the Geological Society of Denmark","volume":"65 1","pages":"1-23"},"PeriodicalIF":1.2,"publicationDate":"2017-02-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45345898","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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