Norwegian Journal of Geology最新文献

{"title":"The use of Sr isotope stratigraphy to date the Pleistocene sediments of the Norwegian continental shelf – a review","authors":"T. Eidvin, D. Ottesen, K. Dybkjær, E. Rasmussen, F. Riis","doi":"10.17850/NJG100-3-1","DOIUrl":"https://doi.org/10.17850/NJG100-3-1","url":null,"abstract":"1Norwegian Petroleum Directorate (NPD), Professor Olav Hanssens vei 10, P. O. Box 600, N‒4003 Stavanger, Norway 2Geological Survey of Norway (NGU), Leif Eirikssons vei 39, P. O. Box 6315 Torgarden, N‒7491 Trondheim, Norway 3Geological Survey of Denmark and Greenland (GEUS), Øster Voldgade 10, DK‒1350, Copenhagen K, Denmark","PeriodicalId":49741,"journal":{"name":"Norwegian Journal of Geology","volume":" ","pages":""},"PeriodicalIF":0.8,"publicationDate":"2020-09-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45367293","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Early-Holocene moraine chronology, Sognefjell area, southern Norway: evidence for multiple glacial and climatic fluctuations within the Erdalen Event (~10.2‒9.7 ka)","authors":"R. Shakesby, J. Matthews, S. Winkler, D. Fabel, P. Q. Dresser","doi":"10.17850/njg100-3-2","DOIUrl":"https://doi.org/10.17850/njg100-3-2","url":null,"abstract":"1Department of Geography, College of Science, Swansea University, Singleton Park, Swansea SA2 8PP, UK 2Department of Geography and Geology, Julius-Maximilians University Würzburg, Am Hubland, 97074 Würzburg, Germany 3SUERC AMS Laboratory, Rankine Avenue, Scottish Enterprise Technology Park, East Kilbride G75 0QF, UK","PeriodicalId":49741,"journal":{"name":"Norwegian Journal of Geology","volume":" ","pages":""},"PeriodicalIF":0.8,"publicationDate":"2020-08-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47040396","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Sedimentary facies and reconstruction of a transgressive coastal plain with coal formation, Paleocene, Spitsbergen, Arctic Norway","authors":"C. Lüthje, G. Nichols, Rhodri Jerred","doi":"10.17850/njg100-2-1","DOIUrl":"https://doi.org/10.17850/njg100-2-1","url":null,"abstract":"","PeriodicalId":49741,"journal":{"name":"Norwegian Journal of Geology","volume":" ","pages":""},"PeriodicalIF":0.8,"publicationDate":"2020-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44009298","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Permo–Triassic sedimentary fills and tectonic phases off Mid Norway: seismic investigation of the Trøndelag Platform","authors":"E. B. Kiswaka, M. Felix","doi":"10.17850/njg100-2-3","DOIUrl":"https://doi.org/10.17850/njg100-2-3","url":null,"abstract":"Kiswaka, E.B. & Felix, M. 2020: Permo–Triassic sedimentary fills and tectonic phases off Mid Norway: seismic investigation of the Trøndelag Platform. Norwegian Journal of Geology 100, 202009. https://dx.doi.org/10.17850/njg100-2-3. © Copyright the authors. This work is licensed under a Creative Commons Attribution 4.0 International License. Seismic interpretation (2D and new 3D surveys) has been used to investigate sedimentary fills and timing of tectonic activity offshore Mid Norway. This study was focused on upper Permian and Lower Triassic sedimentary basin fills, but a longer stratigraphic interval (Devonian–Upper Triassic) was analysed in order to get a broad understanding of what happened prior to, during and after deposition of the upper Permian–Lower Triassic successions. The ages of the sedimentary fills were partly constrained by well ties. Seismic reflectors and sedimentary successions below the upper Permian interval are of Late Devonian– mid Permian age. Six sedimentary fill geometries (fill type A – F) were identified. These are (A) fault-ward thickening packages with internal strata thickening towards bounding faults, (B) wedge-shaped packages whose internal strata have more or less uniform thickness, (C) sedimentary fills containing fill type A overlain by sedimentary strata with more or less uniform thickness, (D) gently dipping packages that thicken towards deeper areas of the basin, and downlap onto pre-existing topography, (E) gently dipping strata filling depressions, and (F) sedimentary wedge with rotated internal strata and folded top. These fill types were used to determine phases of active tectonics and quiescent phases. Based on temporal changes of the fill types, five late Palaeozoic–Triassic unconformities have been mapped: a nonconformity where the Palaeozoic strata onlap onto the basement, a mid-Permian unconformity, two Early Triassic unconformities and a Middle Triassic angular unconformity. Results show that Devonian– Permian, mid-Permian, latePermian, Early Triassic, late Early Triassic, and Mid–Late Triassic rifts influenced","PeriodicalId":49741,"journal":{"name":"Norwegian Journal of Geology","volume":" ","pages":""},"PeriodicalIF":0.8,"publicationDate":"2020-07-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46138073","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Magnetic mapping of fault zones in the Leka Ophiolite Complex, Norway","authors":"A. Michels, C. Fichler, Z. Pastore, S. McEnroe","doi":"10.17850/njg100-1-1","DOIUrl":"https://doi.org/10.17850/njg100-1-1","url":null,"abstract":"Michels, A., Fichler, C., Pastore, Z. and McEnroe, S. 2020: Magnetic mapping of fault zones in the Leka Ophiolite Complex, Norway. Norwegian Journal of Geology 100, 202003. https://dx.doi.org/10.17850/njg100-1-1 © Copyright the authors. This work is licensed under a Creative Commons Attribution 4.0 International License. The island of Leka and surrounding skerries expose a complete suite of ophiolitic rocks, which are heavily faulted. Large areas consist of ultramafic rocks, which are locally hydrated and form serpentinites. Faults are commonly fluid pathways and can be areas of increased serpentinization. Because magnetite is a common product of serpentinization such fault zones add to the local magnetic response of the rocks. Here, ground-magnetic data were used in combination with aeromagnetic data to develop models over the major faults across the island. A mapping workflow was developed which uses tilted slabs to represent different zones of magnetization. The magnetic properties of surface-rock samples provided the constraints for the magnetic modeling. Sensitivity tests on the model showed the detection of magnetic fault zones to be limited to depths shallower than one km. Magnetic modeling allowed for an estimation of the magnetization of several major faults. The magnetic zone of one of the largest faults, which forms the boundary between gabbro and ultramafic rocks, had an enhanced magnetization over a width of approximately 200 m. The model is supported by both ground and aeromagnetic data: the first helped in refining the magnetization distribution at shallower depth, the latter allowed for modeling of the deeper part of the fault, indicating the geometry of a listric fault. The total magnetizations of the modeled slabs are well above the background magnetization of the Leka Ophiolite Complex (LOC) determined by modeling and on magnetic property data on >500 samples. This shift towards higher values indicates that serpentinization in some of the fault zones contributes significantly to the magnetic anomalies of the LOC.","PeriodicalId":49741,"journal":{"name":"Norwegian Journal of Geology","volume":" ","pages":""},"PeriodicalIF":0.8,"publicationDate":"2020-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47068183","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A naturally fractured chalk reservoir in the Ekofisk Formation: characteristics, petrography and stable isotope signature of cemented fractures and faults (The Kraka Field, Danish North Sea)","authors":"A. C. Glad, F. Amour, M. Welch, O. Clausen, H. Nick","doi":"10.17850/njg100-2-4","DOIUrl":"https://doi.org/10.17850/njg100-2-4","url":null,"abstract":"Natural fractures occur in chalk from the Kraka Field (Danian Ekofisk Formation, Southern Danish Sea) and contribute to an increased effective permeability in the reservoir. The majority of fractures are open and act as conduits for hydrocarbons to migrate through. However, some fractures are cemented and thus act as barriers for fluid flow. Predicting porosity and fluid flow in subsurface carbonate reservoirs is challenging, and with a proper understanding of cementation in fractures these subjects are better understood. Further knowledge on cemented fractures can be useful for hydrocarbon exploration and production. This study investigates cemented fractures, faults and a cataclastic fault zone in chalk cores from the Kraka Field. Emphasis is given to small-scale fractures. These are either partially or fully cemented by mineral precipitates, commonly calcite, and have apparent widths of up to 5 mm. One type of fractures has silica cement along the fracture edge and calcite in the central part, while another type only contains blocky calcite cement. The faults have apparent widths up to 5 cm and are partially cemented by calcite. The cataclastic fault zone has an apparent width of 25 cm and is filled with angular fragments of chalk cemented by blocky calcite. Stable isotope analysis of the cement in the fractures and the cataclastic fault zone suggests that they were filled by calcite cement almost simultaneously during burial. The paragenetic sequence of Danian chalk from the Kraka Field is reconstructed and compared with that of other North Sea fields. Based on an investigation of cemented fractures in the Kraka Field, this study provides information on cementation evolution and possible implications for porosity and fluid flow. The majority of Danish faults, and one example of a cataclastic fault zone. The distinction between fractures","PeriodicalId":49741,"journal":{"name":"Norwegian Journal of Geology","volume":" ","pages":""},"PeriodicalIF":0.8,"publicationDate":"2020-06-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49217522","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The deep geothermal potential of the radiogenic Løvstakken Granite in western Norway","authors":"M. Frey, J. Ebbing","doi":"10.17850/njg100-1-4","DOIUrl":"https://doi.org/10.17850/njg100-1-4","url":null,"abstract":"Frey, M. & Ebbing, J. 2020: The deep geothermal potential of the radiogenic Løvstakken Granite in western Norway. Norwegian Journal of Geology 100, 202004. https://dx.doi.org/10.17850/njg100-1-4. © Copyright the authors. This work is licensed under a Creative Commons Attribution 4.0 International License. We developed a first detailed 3D crustal model of the Bergen Region by combining geological information with gravity and magnetic data in order to estimate the geothermal potential of the Løvstakken Granite, which shows a particularly high concentration of radioactive elements. The geometry of the near-surface horizons in the model is consistent with geological observations and interpretations. The basement structure is, in contrast, associated with greater uncertainties due to the lack of land seismic or deep borehole data. To improve the geological model, we performed stochastic inversions of the gravity and magnetic fields resulting in three plausible models for the Løvstakken Granite. Based on these modelling results, the subsurface temperatures were predicted by numerical simulation and the various influencing factors were investigated, whilst the 516 m-deep Fyllingsdalen borehole provided important thermal constraints. Especially the radiogenic heat production affects the thermal structure of the crust in the Bergen Arcs and we show that the concentration of radioactive elements in the entire basement is on average 50% smaller than at the surface. The geometry of the Løvstakken Granite also influences the geothermal gradient, but the differences between the three crustal models of 3°C/km are rather moderate. Furthermore, a correction for the paleoclimatic conditions in western Norway is applied which has an effect of up to 7 ± 4°C. Lastly, the groundwater influence was determined by creating a coupled fluid flow and heat transport model. Local temperature changes of up to ± 5°C are found, but there is no significant cooling at the Fyllingsdalen borehole due to groundwater. According to the calculated geothermal gradient in the Bergen Arcs System, the potential for the generation of electricity is relatively low. In comparison, there is an intermediate potential for the extraction of heating energy, in particular in the urban area of Bergen.","PeriodicalId":49741,"journal":{"name":"Norwegian Journal of Geology","volume":" ","pages":""},"PeriodicalIF":0.8,"publicationDate":"2020-06-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45465177","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Late Neoproterozoic basin evolution of the magma rich Iapetus margin of Baltica","authors":"H. J. Kjøll","doi":"10.17850/njg100-1-6","DOIUrl":"https://doi.org/10.17850/njg100-1-6","url":null,"abstract":"Kjøll, H.J. 2020: Late Neoproterozoic basin evolution of the magma-rich Iapetus margin of Baltica. Norwegian Journal of Geology 100, 202005, https://dx.doi.org/10.17850/njg100-1-6. © Copyright the authors. This work is licensed under a Creative Commons Attribution 4.0 International License. The Särv and Seve nappe complexes (NC) in the central and northern Scandinavian Caledonides locally display well-preserved, mafic dyke-intruded sedimentary successions commonly interpreted to have been deposited in sagto rift basins along the margin of the Iapetus Ocean. The sedimentary successions are generally interpreted to have been deposited prior to or during the Late Neoproterozoic opening of the Iapetus Ocean. They were later incorporated into the Scandinavian Caledonides during the Silurian-aged Scandian orogeny. Whereas the minimum depositional age is constrained by the dated mafic dyke swarm at c. 596‒608 Ma, a maximum depositional age for the sedimentary successions is poorly constrained. No fossils or diamictite units have hitherto been reported from the sedimentary successions found in the Seve NC. This contribution presents new geological observations and geochronological data from allochthonous, dyke-intruded, rift-related basins. Key elements in the sedimentary succession, such as carbonates with meta-evaporitic domains, diamictite and stromatolites are described from the Särv and Seve NC. Evidence presented here suggests that the diamictite is of glaciogenic origin. It is cut by the dykes and is therefore older than 608 Ma and could be related to the Marinoan or Sturtian glaciations. The stromatolite resembles Eleonora laponica and is found below the diamictite. Two field areas have young detrital zircons of c. 700‒750 Ma providing possible upper maximum depositional ages and thus bracket the deposition within a c. 100 M.yr. time interval between 700 and 608. This is corroborated by a Palaeoproterozoic orthogneiss with a 631 Ma Pb-loss event, possibly reflecting the development of a top-west, ductile extensional shear fabric and frictional co-seismic deformation. This extensional event generated accommodation space at the surface and thus basin formation. Similarities between the separate basins, like the highly dyke-intruded nature, the similarities in contact and regional metamorphism as well as the detrital zircon age distributions, suggest that the basins are related.","PeriodicalId":49741,"journal":{"name":"Norwegian Journal of Geology","volume":" ","pages":""},"PeriodicalIF":0.8,"publicationDate":"2020-06-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45699948","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Notes on Ordovician graptolites, nautiloids and trace fossils from Lånke, Central Norwegian Caledonides","authors":"M. Smelror, T. Solbakk, B. I. Rindstad, Helle Vangen Stuedal, K. Hårsaker","doi":"10.17850/njg100-2-2","DOIUrl":"https://doi.org/10.17850/njg100-2-2","url":null,"abstract":"1Geological Survey of Norway, P.O. Box 6315 Torgarden, 7491 Trondheim, Norway 2Norwegian University of Science and Technology, S.P. Andersens vei 15B, 7491 Trondheim, Norway Present address: Geological Survey of Norway, P.O.Box 6315 Torgarden, 7491 Trondheim, Norway 3Stjørdal Museum Værnes, Prestmovegen 2, 7500 Stjørdal, Norway 4NTNU Vitenskapsmuseet, Erling Skakkes gate 47A, 7012 Trondheim, Norway","PeriodicalId":49741,"journal":{"name":"Norwegian Journal of Geology","volume":"1 1","pages":""},"PeriodicalIF":0.8,"publicationDate":"2020-06-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42975422","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"On the the origin of the Yermak Plateau north of Svalbard, Arctic Ocean","authors":"Y. Kristoffersen, Y. Ohta, J. Hall","doi":"10.17850/njg100-1-5","DOIUrl":"https://doi.org/10.17850/njg100-1-5","url":null,"abstract":"On the the Plateau in the Arctic north The Yermak Plateau north of Spitsbergen and Morris Jesup Spur and rise north of Greenland relate to the Late Cretaceous-early Cenozoic interaction between an independent Greenland plate and the larger North American and European plates. We have recovered 21 new dredge hauls from three locations on the Yermak Plateau with an abundance of metasedimentary and gneissic rocks with strong affinities to known lithologies from northwest Spitsbergen. The continental outlier requires Paleogene dextral shear close to the coast of West Spitsbergen to accommodate opening of the Sophia Basin between the plateau and the continental margin. The postulated large-offset (100–150 km) shear zone (de Geer Fault) is supported by seismic velocity anomalies down to mid-crustal levels, a ubiquitous feature of known large-offset continental transform faults regardless of crustal rock composition. A continental sliver including the Yermak Plateau and Prins Karls Forland initially moved with Greenland along the de Geer Fault during the early Eocene stage of Eurasia Basin opening and facilitated opening of the Sophia Basin north of Spitsbergen by crustal extension. Later offset of the de Geer Fault north of Spitsbergen and formation of the Danskøya Basin in a transfer zone was probably induced by a restraining bend in the Hornsund Fault Zone active at the same time. The 65 km-wide, circular-shaped, northeastern tip of the Yermak Plateau is a young volcanic feature formed between Chron 22 and Chron 18 at the junction between the Gakkel Ridge and the Yermak continental block before separation of the Morris Jesup Spur and Yermak Plateau. The Yermak Plateau became part of the European plate prior to Chron 13 as the Gakkel Ridge propagated into the Northeast Greenland margin and the subsequent dextral motion shifted west to the Hornsund Fault Zone. The de Geer Fault and the Hornsund Fault Zone may have been in existence at the same time. E-mail (Yngve","PeriodicalId":49741,"journal":{"name":"Norwegian Journal of Geology","volume":" ","pages":""},"PeriodicalIF":0.8,"publicationDate":"2020-06-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45054482","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}