Sverre Planke

• Bellwald, Benjamin; Planke, Sverre; Lebedeva-Ivanova, Nina; Piasecka, Emilia Daria & Andreassen, Karin (2019). High-resolution landform assemblage along a buried glacio-erosive surface in the SW Barents Sea revealed by P-Cable 3D seismic data. Geomorphology.  ISSN 0169-555X.  332, s 33- 50 . doi: 10.1016/j.geomorph.2019.01.019 Vis sammendrag

  The Quaternary sedimentary record in the Arctic captures a diverse and evolving range of landscapes reflecting cli-mate changes. Here we study the geological landform assemblage of the Upper Regional Unconformity (URU) in theSW Barents Sea. The aims are (i) to characterize buried geological landforms on a meter-scale resolution, (ii) to un-derstand their link with underlying structures, and (iii) to reconstruct paleo-ice-sheet dynamics and configurations.The data consist of a high-resolution three-dimensional (3D) P-Cable seismic cube with an extent of c. 200 km2andan inline separation of 6 m. Dominant frequencies of c. 150 Hz allow to image landforms at URU with a vertical res-olution of 1–5 m and a horizontal resolution of 3–6 m. We conduct detailed horizon-picking and seismic attributeanalysis of the buried URU horizon. We identified four sets of mega-scale glacial lineations, and shear band ridgeslocated to the west of a shear margin moraine. Other characteristic features include hill-hole pairs, transverse ridges,rhombohedral ridges and depressions, iceberg ploughmarks and pockmarks. Polygonal faults below URU anddeeper faults have a strong effect on the location of structures observed on URU. Bedrock packages deformeddown to 30 m below URU and up to 5 m-high transverse ridges at URU are imprints of glacio-tectonic activity.Deformed strata below URU indicate normal faulting superimposed by glaciotectonic deformation. The four setsof mega-scale glacial lineations indicate four streaming events with thawed glacial beds, with shear band ridgesforming in the shearing zone during one of these streaming events. Hill-hole pairs and rhombohedral ridges arefrozen-bed features which indicate a polythermal regime at the base of the Barents Sea Ice Sheet during multiplestreaming phases. This study therefore shows that paleo-ice streams have been temporarily frozen to the groundin the SW Barents Sea, and that landforms evidencing this freezing are associated with underlying faults.

• Heimdal, Thea Hatlen; Callegaro, Sara; Svensen, Henrik; Jones, Morgan Thomas; Pereira, Egberto & Planke, Sverre (2019). Evidence for magma–evaporite interactions during the emplacement of the Central Atlantic Magmatic Province (CAMP) in Brazil. Earth and Planetary Science Letters.  ISSN 0012-821X.  506, s 476- 492 . doi: 10.1016/j.epsl.2018.11.018
• Tegner, Christian; Andersen, Torgeir Bjørge; Kjøll, Hans Jørgen; Brown, Eric L.; Hagen-Peter, Graham; Corfu, Fernando; Planke, Sverre & Torsvik, Trond Helge (2019). A mantle plume origin for the Scandinavian Dyke Complex: a "piercing point" for 615 Ma plate reconstruction of Baltica?. Geochemistry Geophysics Geosystems.  ISSN 1525-2027. . doi: 10.1029/2018GC007941 Fulltekst i vitenarkiv. Vis sammendrag

  Abstract The origin of Large Igneous Provinces (LIPs) associated with continental breakup and the reconstruction of continents older than c. 320 million years (pre-Pangea) are contentious research problems. Here we study the petrology of a 615 - 590 Myr dolerite dyke complex that intruded rift-basins of the magma-rich margin of Baltica and now is exposed in the Scandinavian Caledonides. These dykes are part of the Central Iapetus Magmatic Province (CIMP), a LIP emplaced in Baltica and Laurentia during opening of the Caledonian Wilson Cycle. The >1000 km long dyke complex displays lateral geochemical zonation from enriched to depleted basaltic compositions from south to north. Geochemical modelling of major and trace elements shows these compositions are best explained by melting hot mantle 75-250°C above ambient mantle. Although the trace element modelling solutions are non- unique, the best explanation involves melting a laterally zoned mantle plume with enriched and depleted peridotite lithologies, similar to present-day Iceland and to the North Atlantic Igneous Province. The origin of CIMP appears to have involved several mantle plumes. This is best explained if rifting and breakup magmatism coincided with plume generation zones at the margins of a Large Low Shear-wave Velocity Province (LLSVP) at the core mantle boundary. If the LLSVPs are quasi-stationary back in time as suggested in recent geodynamic models, the CIMP provides a guide for reconstructing the paleogeography of Baltica and Laurentia 615 million years ago to the LLSVP now positioned under the Pacific Ocean. Our results provide a stimulus for using LIPs as piercing points for plate reconstructions.

• Abdelmalak, Mohamed Mansour; Planke, Sverre; Polteau, Stephane; Hartz, Ebbe Hvidegård; Faleide, Jan Inge; Tegner, Christian; Jerram, Dougal Alexander; Millett, John M & Myklebust, Reidun (2018). Breakup volcanism and plate tectonics in the NW Atlantic. Tectonophysics.  ISSN 0040-1951. . doi: 10.1016/j.tecto.2018.08.002
• Bellwald, Benjamin & Planke, Sverre (2018). Shear margin moraine, mass transport deposits and soft beds revealed by high-resolution P-Cable three dimensional seismic data in the Hoop area, Barents Sea. Geological Society Special Publication.  ISSN 0305-8719.  477 . doi: 10.1144/SP477.29
• Bellwald, Benjamin; Planke, Sverre; Piasecka, Emilia Daria; Matar, Mohammed A. & Andreassen, Karin (2018). Ice-stream dynamics of the SW Barents Sea revealed by high-resolution 3D seismic imaging of glacial deposits in the Hoop area. Marine Geology.  ISSN 0025-3227.  402, s 165- 183 . doi: 10.1016/j.margeo.2018.03.002 Fulltekst i vitenarkiv.
• Corseri, Romain; Faleide, Thea Sveva; Faleide, Jan Inge; Midtkandal, Ivar; Serck, Christopher Sæbø; Trulsvik, Mikal & Planke, Sverre (2018). A diverted submarine channel of Early Cretaceous age revealed by high-resolution seismic data, SW Barents Sea. Marine and Petroleum Geology.  ISSN 0264-8172.  98, s 462- 476 . doi: 10.1016/j.marpetgeo.2018.08.037 Fulltekst i vitenarkiv.
• Galland, Olivier; Bertelsen, Håvard Svanes; Eide, Christian Haug; Guldstrand, Frank Bo Buster; Haug, Øystein Thorden; Leanza, Hector Armando; Mair, Karen; Palma, Octavio; Planke, Sverre; Rabbel, Ole; Rogers, Benjamin David; Schmiedel, Tobias; Souche, Alban & Spacapan, Juan Bautista (2018). Storage and Transport of Magma in the Layered Crust—Formation of Sills and Related Flat-Lying Intrusions, In Steffi Burchardt (ed.),  Volcanic and Igneous Plumbing Systems - Understanding Magma Transport, Storage, and Evolution in the Earth's Crust.  Elsevier.  ISBN 978-0-12-809749-6.  Chapter 5.  s 113 - 138 Vis sammendrag

  Even though dykes are the main upward magma pathways through the Earth’s crust, the last two decades of research showed that significant parts of volcano plumbing systems consist of flat-lying igneous intrusions, namely sills. Sills form mainly in the layered parts of the crust, principally in volcanic deposits and sedimentary basins. Sills exhibit various shapes, strata-concordant, transgressive sheets, and saucer-shaped. Lateral magma flow through sill complexes and networks can reach several hundred kilometres. Sills represent intermediate feeder structures for volcanic eruptions, and therefore better understanding of sill emplacement and evolution is essential for assessing volcanic hazards. Sills emplaced in sedimentary basins also deeply affect petroleum systems and are essential components in exploring hydrocarbons. Finally, the massive and fast emplacement of sills resulting from LIPs in sedimentary basins triggered catastrophic climate changes and mass extinctions during Earth's history.

• Karstens, Jens; Haflidason, Haflidi; Becker, Lukas; Berndt, Christian; Rüpke, Lars Helmuth; Planke, Sverre; Liebetrau, Volker; Schmidt, Markus & Mienert, Jurgen (2018). Glacigenic sedimentation pulses triggered postglacial gas hydrate dissociation. Nature Communications.  ISSN 2041-1723.  9 . doi: 10.1038/s41467-018-03043-z Fulltekst i vitenarkiv.
• Kastner, Felix; Giese, Rudiger; Planke, Sverre; Millett, John M & Flovenz, Olafur G (2018). Seismic imaging in the Krafla high-temperature geothermal field, NE Iceland, using zero- and far-offset vertical seismic profiling (VSP) data. Journal of Volcanology and Geothermal Research.  ISSN 0377-0273. . doi: 10.1016/j.jvolgeores.2018.02.016
• Lebedeva-Ivanova, Nina; Polteau, Stephane; Bellwald, Benjamin; Planke, Sverre; Berndt, Christian & Stokke, Henrik Henriksen (2018). Toward one-meter resolution in 3D seismic. The Leading Edge.  ISSN 1070-485X.  37(11), s 818- 828 . doi: 10.1190/tle37110818.1
• Lerch, Benedikt; Karlsen, Dag Arild; Thießen, Olaf; Abay, Tesfamariam Berhane; van Soelen, Elsbeth Ester; Kürschner, Wolfram Michael; Planke, Sverre & Backer-Owe, Kristian (2018). Investigations on the use of triaromatic dimethylcholesteroids as age-specific biomarkers in bitumens and oils from Arctic Norway. Organic Geochemistry.  ISSN 0146-6380.  122, s 1- 16 . doi: 10.1016/j.orggeochem.2018.04.011
• Millett, J.M.; Planke, Sverre; Kastner, Felix; Blischke, A; Hersir, Gylfi Pall; Halldorsdottir, Sæunn; Flovenz, Olafur G; Arnadottir, S; Helgadottir, H.M.; Vakulenko, Sergey; Buryak, S; Erlendsson, Ögmundur; Giese, Rudiger; Cavailhes, Jehanne P.; Jerram, Dougal Alexander; Gudmundsson, Asgrimur & Juliusson, Egill (2018). Sub-surface geology and velocity structure of the Krafla high temperature geothermal field, Iceland: Integrated ditch cuttings, wireline and zero offset vertical seismic profile analysis.. Journal of Volcanology and Geothermal Research.  ISSN 0377-0273. . doi: 10.1016/j.jvolgeores.2018.03.024
• Planke, Sverre; Rabbel, Ole; Galland, Olivier; Millet, John; Manson, Ben; Jerram, Dougal Alexander; Palma, Octavio & Spacapan, Juan Bautista (2018). Seismic imaging and petroleum implications of igneous intrusions in sedimentary basins constrained by outcrop analogues and seismic data from the Neuquén Basin and the NE Atlantic, In Luis Vernengo; Mario Atencio; Marcela Branca; Eduardo Corti; Tomás D'Biassi; Jorge Dario Enrique; Maximiliano García Torrejón; Luis Pianelli; Alberto Ricardi; Daniel Soubiés & Federico Späth (ed.),  10 Congreso de Exploración y Desarrollo de Hidrocarburos - Simposio de Geofísica: La geofísica como vinculo entre el conocimiento de la tierra y la sociedad.  Instituto Argentino del Petroleo y del Gas.  ISBN 978-987-9139-92-9.  Article.  s 343 - 366
• Polteau, S.; Lebedeva-Ivanova, Nina; Bellwald, Benjamin; Planke, Sverre; Zastrozhnov, Dmitry; Vanneste, Maarten; Sauvin, Guillaume; Myklebust, R.; Bünz, Stefan; Plaza-Faverola, Andreia; Waage, Malin & Berndt, C (2018). High-Resolution 3D Site Characterization, In NN NN (ed.),  3rd Applied Shallow Marine Geophysics Conference, Near Surface Geoscience Conference & Exhibition 2018.  European Association of Geoscientists and Engineers.  ISBN 9789462822641.  x. Vis sammendrag

  We present the results of a novel method for high-resolution 3D site characterization. The strategy is based on using 3D seismic data as the framework for integrating geochemical, geophysical and geotechnical data. The end-results are 3D volumes with various attributes relevant for improved site characterization and ultimately geohazard assessment (i.e. identification of shallow gas, boulders, faults and fractures, leakage, spatial variability, soil strength…). We further show that geochemical data integrated with current high-resolution 3D seismic data can be used to constrain fluid migration pathways to the seafloor. In addition, re-processing focusing on the higher frequencies of 3D seismic data increases the resolution, resulting in a data volume displaying more details on the geology and geomorphology of the sub-surface when compared to data processed for deeper imaging. Finally, we configured an optimized 3D seismic acquisition system, which is fine-tuned for imaging the top 150 m of overburden with a meter-scale lateral and vertical resolution. Such a high-resolution 3D seismic system would provide data volumes that allow well-constrained integration of various type of data.

• Polteau, Stephane; Mazzini, Adriano; Hansen, Geir; Planke, Sverre; Jerram, Dougal Alexander; Millett, John; Abdelmalak, Mohamed Mansour; Blischke, Anett & Myklebust, Reidun (2018). The pre-breakup stratigraphy and petroleum system of the Southern Jan Mayen Ridge revealed by seafloor sampling. Tectonophysics.  ISSN 0040-1951. . doi: 10.1016/j.tecto.2018.04.016
• Reiser, Fabienne; Schmelzbach, Cedric; Sollberger, David; Maurer, Hansruedi; Greenhalgh, Stewart; Planke, Sverre; Kastner, Felix; Flovenz, Olafur G; Giese, Rudiger; Halldorsdottir, Sæunn & Hersir, Gylfi Pall (2018). Imaging the high-temperature geothermal field at Krafla using vertical seismic profiling. Journal of Volcanology and Geothermal Research.  ISSN 0377-0273. . doi: 10.1016/j.jvolgeores.2018.10.019
• Svensen, Henrik; Frolov, Sergei; G., Akhmanov; Polozov, Alexander; Jerram, Dougal Alexander; Shiganova, O.; Melnikov, N.; Iyer, K. & Planke, Sverre (2018). Sills and gas generation in the Siberian Traps. Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences.  ISSN 1364-503X.  376(2130) . doi: 10.1098/rsta.2017.0080
• Svensen, Henrik; Torsvik, Trond Helge; Callegaro, Sara; Augland, Lars Eivind; Heimdal, Thea Hatlen; Jerram, Dougal Alexander; Planke, Sverre & Pereira, Egberto (2018). Gondwana large igneous provinces: plate reconstructions, volcanic basins and sill volumes. In: Large Igneous Provinces from Gondwana and Adjacent Regions. Geological Society Special Publication.  ISSN 0305-8719.  463, s 17- 40 . doi: 10.1144/SP463.7
• Tasianas, Alexandros; Bünz, Stefan; Bellwald, Benjamin; Hammer, Øyvind; Planke, Sverre; Lebedeva-Ivanova, Nina & Krassakis, Pavlos (2018). High-resolution 3D seismic study of pockmarks and shallow fluid flow systems at the Snøhvit hydrocarbon field in the SW Barents Sea. Marine Geology.  ISSN 0025-3227.  403, s 247- 261 . doi: 10.1016/j.margeo.2018.06.012 Fulltekst i vitenarkiv.
• Zastrozhnov, Dmitrii; Gernigon, Laurent; Gogin, I; Abdelmalak, Mohamed Mansour; Planke, Sverre; Faleide, Jan Inge; Eide, S. & Myklebust, R. (2018). Cretaceous-Paleocene Evolution and Crustal Structure of the Northern V?ring Margin (Offshore Mid-Norway): Results from Integrated Geological and Geophysical Study. Tectonics.  ISSN 0278-7407.  37(2), s 497- 528 . doi: 10.1002/2017TC004655
• Abdelmalak, Mohamed Mansour; Faleide, Jan Inge; Planke, Sverre; Gernigon, Laurent; Zastrozhnov, Dmitry; Shephard, Grace & Myklebust, Reidun (2017). The T-Reflection and the Deep Crustal Structure of the Vøring Margin, Offshore mid-Norway. Tectonics.  ISSN 0278-7407.  36(11), s 2497- 2523 . doi: 10.1002/2017TC004617 Fulltekst i vitenarkiv.
• Angkasa, Syahreza Saidina; Jerram, Dougal Alexander; Millett, John M; Svensen, Henrik; Planke, Sverre; Taylor, Ross A; Schofield, Nick & Howell, John (2017). Mafic intrusions, hydrothermal venting and the basalt-sediment transition: Linking onshore and offshore examples from the north atlantic igneous province. Interpretation.  ISSN 2324-8858.  5(3) . doi: 10.1190/int-2016-0162.1 Fulltekst i vitenarkiv.
• Corseri, Romain; Senger, Kim; Selway, Katherine; Abdelmalak, Mohamed Mansour; Planke, Sverre & Jerram, Dougal Alexander (2017). Magnetotelluric evidence for massive sulphide mineralization in intruded sediments of the outer Vøring Basin, mid-Norway. Tectonophysics.  ISSN 0040-1951.  706-707, s 196- 205 . doi: 10.1016/j.tecto.2017.04.011 Fulltekst i vitenarkiv.
• Fristad, Kirsten; Svensen, Henrik; Polozov, Alexander & Planke, Sverre (2017). Formation and evolution of the end–Permian Oktyabrsk volcanic crater in the Tunguska Basin, Eastern Siberia. Palaeogeography, Palaeoclimatology, Palaeoecology.  ISSN 0031-0182.  468, s 76- 87 . doi: 10.1016/j.palaeo.2016.11.025
• Hafeez, Amer; Planke, Sverre; Jerram, Dougal Alexander; Millett, John M; Maharjan, Dwarika & Prestvik, Tore (2017). Upper paleocene ultramafic igneous rocks offshore mid-Norway: Re-interpretation of the vestbrona formation as a sill complex. Interpretation.  ISSN 2324-8858.  5(3), s SK103- SK120 . doi: 10.1190/int-2016-0143.1 Fulltekst i vitenarkiv.
• Iyer, Karthik Herman; Schmid, Daniel Walter; Planke, Sverre & Millett, John (2017). Modelling hydrothermal venting in volcanic sedimentary basins: Impact on hydrocarbon maturation and paleoclimate. Earth and Planetary Science Letters.  ISSN 0012-821X.  467, s 30- 42 . doi: 10.1016/j.epsl.2017.03.023 Fulltekst i vitenarkiv.
• Jones, Morgan Thomas; Augland, Lars Eivind; Shephard, Grace; Burgess, Seth; Eliassen, Gauti Trygvason; Jochmann, Malte; Friis, Bjarki; Jerram, Dougal Alexander; Planke, Sverre & Svensen, Henrik (2017). Constraining shifts in North Atlantic plate motions during the Palaeocene by U-Pb dating of Svalbard tephra layers. Scientific Reports.  ISSN 2045-2322.  7(1) . doi: 10.1038/s41598-017-06170-7 Fulltekst i vitenarkiv.
• Kjoberg, Sigurd; Schmiedel, Tobias; Planke, Sverre; Svensen, Henrik; Millett, John; Jerram, Dougal Alexander; Galland, Olivier; Lecomte, Isabelle; Schofield, Nick; Haug, Øystein Thorden & Helsem, Andreas (2017). 3D structure and formation of hydrothermal vent complexes at the paleocene-eocene transition, the Møre basin, MID-Norwegian margin. Interpretation.  ISSN 2324-8858.  5(3), s SK65- SK81 . doi: 10.1190/int-2016-0159.1 Fulltekst i vitenarkiv. Vis sammendrag

  The mid-Norwegian margin is regarded as an example of a volcanic-rifted margin, formed prior to and during, Paleogene breakup of the northeast Atlantic. The area is characterized by the presence of voluminous basaltic complexes such as extrusive lava and lava delta sequences, intrusive sills and dikes, and hydrothermal vent complexes. We have developed a detailed 3D seismic analysis of fluid-and gas-induced hydrothermal vent complexes in a 310 km2 area in the Møre Basin, offshore Norway. We find that formation of hydrothermal vent complexes is accommodated by deformation of the host rock when sills are emplaced. Fluids are generated by metamorphic reactions and pore-fluid expansion around sills and are focused around sill tips due to buoyancy. Hydrothermal vent complexes are associated with doming of the overlying strata, leading to the formation of draping mounds above the vent contemporary surface. The morphological characteristics of the upper part and the underlying feeder structure (conduit zone) are imaged and studied in 3D seismic data. Well data indicate that the complexes formed during the early Eocene, linking their formation to the time of the Paleocene-Eocene thermal maximum at c. 56 Ma. The well data further suggest that the hydrothermal vent complexes were active for a considerable time period, corresponding to a c. 100 m thick transition zone unit with primary Apectodinium augustum and redeposited very mature Cretaceous and Jurassic palynomorphs. The newly derived understanding of age, structure, and formation of hydrothermal vent complexes in the Møre Basin contributes to the general understanding of the igneous plumbing system in volcanic basins and their implications for the paleoclimate and petroleum systems.

• Mazzini, Adriano; Svensen, Henrik; Forsberg, Carl Fredrik; Linge, Henriette; Lauritzen, Stein-Erik; Haflidason, Haflidi; Hammer, Øyvind; Planke, Sverre & Tjelta, Tor-Inge (2017). A climatic trigger for the giant Troll pockmark field in the northern North Sea. Earth and Planetary Science Letters.  ISSN 0012-821X.  464, s 24- 34 . doi: 10.1016/j.epsl.2017.02.014 Fulltekst i vitenarkiv. Vis sammendrag

  Pockmarks are seafloor craters usually formed during methane release on continental margins. However, the mechanisms behind their formation and dynamics remain elusive. Here we report detailed investigations on one of the World's largest pockmark fields located in the Troll region in the northern North Sea. Seafloor investigations show that >7000 pockmarks are present in a ∼600 km2 area. A similar density of pockmarks is likely present over a 15,000 km2 region outside our study area. Based on extensive monitoring, coring, geophysical and geochemical analyses, no indications of active gas seepage were found. Still, geochemical data from carbonate blocks collected from these pockmarks indicate a methanogenic origin linked to gas hydrate dissociation and past fluid venting at the seafloor. We have dated the carbonates using the U–Th method in order to constrain the pockmark formation. The carbonates gave an isochron age of 9.59±1.38 ka9.59±1.38 ka, i.e. belonging to the initial Holocene. Moreover, radiocarbon dating of microfossils in the sediments inside the pockmarks is consistent with the ages derived from the carbonates. Based on pressure and temperature modelling, we show that the last deglaciation could have triggered dissociation of gas hydrates present in the region of the northern part of the Norwegian Channel, causing degassing of 0.26 MtCH4/km2 at the seafloor. Our results stress the importance of external climatic forcing of the dynamics of the seafloor, and the role of the rapid warming following the Younger Dryas in pacing the marine gas hydrate reservoir.

• Planke, Sverre; Millett, John M; Maharjan, Dwarika; Jerram, Dougal Alexander; Abdelmalak, Mohamed Mansour; Groth, Audun; Hoffmann, Jasper; Berndt, Christian & Myklebust, Reidun (2017). Igneous seismic geomorphology of buried lava fields and coastal escarpments on the Vøring volcanic rifted margin. Interpretation.  ISSN 2324-8858.  5(3), s SK161- SK177 . doi: 10.1190/INT-2016-0164.1 Fulltekst i vitenarkiv.
• Reynolds, P.; Planke, Sverre; Millett, J.M.; Jerram, Dougal Alexander; Trulsvik, M.; Schofield, N. & Myklebust, R. (2017). Hydrothermal vent complexes offshore Northeast Greenland: A potential role in driving the PETM. Earth and Planetary Science Letters.  ISSN 0012-821X.  467, s 72- 78 . doi: 10.1016/j.epsl.2017.03.031 Fulltekst i vitenarkiv.
• Schmiedel, Tobias; Kjoberg, Sigurd; Planke, Sverre; Magee, Craig; Galland, Olivier; Schofield, Nick; Jackson, Christopher A.-L. & Jerram, Dougal Alexander (2017). Mechanisms of overburden deformation associated with the emplacement of the Tulipan sill, mid-Norwegian margin. Interpretation.  ISSN 2324-8858.  5(3), s SK23- SK38 . doi: 10.1190/INT-2016-0155.1 Fulltekst i vitenarkiv. Vis sammendrag

  The emplacement of igneous intrusions into sedimentary basins mechanically deforms the host rocks and causes hydrocarbon maturation. Existing models of host-rock deformation are investigated using high-quality 3D seismic and industry well data in the western Møre Basin offshore mid-Norway. The models include synemplacement (e.g., elastic bending-related active uplift and volume reduction of metamorphic aureoles) and postemplacement (e.g., differential compaction) mechanisms. We use the seismic interpretations of five horizons in the Cretaceous-Paleogene sequence (Springar, Tang, and Tare Formations) to analyze the host rock deformation induced by the emplacement of the underlying saucer-shaped Tulipan sill. The results show that the sill, emplaced between 55.8 and 54.9 Ma, is responsible for the overlying dome structure observed in the seismic data. Isochron maps of the deformed sediments, as well as deformation of the younger postemplacement sediments, document a good match between the spatial distribution of the dome and the periphery of the sill. The thickness tt of the Tulipan is less than 100 m, whereas the amplitude ff of the overlying dome ranges between 30 and 70 m. Spectral decomposition maps highlight the distribution of fractures in the upper part of the dome. These fractures are observed in between hydrothermal vent complexes in the outer parts of the dome structure. The 3D seismic horizon interpretation and volume rendering visualization of the Tulipan sill reveal fingers and an overall saucer-shaped geometry. We conclude that a combination of different mechanisms of overburden deformation, including (1) elastic bending, (2) shear failure, and (3) differential compaction, is responsible for the synemplacement formation and the postemplacement modification of the observed dome structure in the Tulipan area.

• Senger, Kim; Millett, John; Planke, Sverre; Ogata, Kei; Eide, Christian Haug; Festøy, Marte Hergot; Galland, Olivier & Jerram, Dougal Alexander (2017). Effects of igneous intrusions on the petroleum system: a review. First Break.  ISSN 0263-5046.  35(6), s 47- 56 . doi: 10.3997/1365-2397.2017011
• Spacapan, Juan Bautista; Galland, Olivier; Leanza, Hector Armando & Planke, Sverre (2017). Igneous sill and finger emplacement mechanism in shale-dominated formations: a field study at Cuesta del Chihuido, Neuquén Basin, Argentina. Journal of the Geological Society.  ISSN 0016-7649.  174(3), s 422- 433 . doi: 10.1144/jgs2016-056
• Abdelmalak, Mohamed Mansour; Meyer, Romain; Planke, Sverre; Faleide, Jan Inge; Gernigon, Laurent; Frieling, J; Sluijs, Appy; Reichart, G-J; Zastrozhnov, Dmitrii; Theissen-Krah, Sonja; Said, Aymen & Myklebust, Reidun (2016). Pre-breakup magmatism on the Vøring margin: Insight from new sub-basalt imaging and results from Ocean Drilling program hole 642E. Tectonophysics.  ISSN 0040-1951.  675, s 258- 274 . doi: 10.1016/j.tecto.2016.02.037
• Abdelmalak, Mohamed Mansour; Planke, Sverre; Faleide, Jan Inge; Jerram, Dougal Alexander; Zastrozhnov, Dmitrii; Eide, Sigurd & Myklebust, Reidun (2016). The development of volcanic sequences at rifted margins: New insights from the structure and morphology of the Vøring Escarpment, mid-Norwegian Margin. Journal of Geophysical Research - Solid Earth.  ISSN 2169-9313.  121(7), s 5212- 5236 . doi: 10.1002/2015JB012788
• Frieling, Joost; Svensen, Henrik; Planke, Sverre; Cramwinckel, Margot J; Selnes, Haavard & Sluijs, Appy (2016). Thermogenic methane release as a cause for the long duration of the PETM. Proceedings of the National Academy of Sciences of the United States of America.  ISSN 0027-8424.  113(43), s 12059- 12064 . doi: 10.1073/pnas.1603348113
• Hammer, Øyvind; Planke, Sverre; Hafeez, Amer; Hjelstuen, Berit Oline Blihovde; Faleide, Jan Inge & Kvalø, Frode (2016). Agderia – A postglacial lost land in the southern Norwegian North Sea. Norsk Geologisk Tidsskrift.  ISSN 0029-196X.  96(1), s 43- 60 . doi: 10.17850/njg96-1-05
• Jones, Morgan Thomas; Trygvason Eliassen, Gauti; Shephard, Grace; Svensen, Henrik; Jochmann, Malte; Friis, Bjarki; Augland, Lars Eivind; Jerram, Dougal Alexander & Planke, Sverre (2016). Provenance of bentonite layers in the Palaeocene strata of the Central Basin, Svalbard: implications for magmatism and rifting events around the onset of the North Atlantic Igneous Province. Journal of Volcanology and Geothermal Research.  ISSN 0377-0273.  327, s 571- 584 . doi: 10.1016/j.jvolgeores.2016.09.014
• Midtkandal, Ivar; Svensen, Henrik; Planke, Sverre; Corfu, Fernando; Polteau, Stephane; Torsvik, Trond Helge; Faleide, Jan Inge; Grundvåg, Sten-Andreas; Selnes, Håvard; Kürschner, Wolfram Michael & Olaussen, Snorre (2016). The Aptian (Early Cretaceous) oceanic anoxic event (OAE1a) in Svalbard, Barents Sea, and the absolute age of the Barremian-Aptian boundary. Palaeogeography, Palaeoclimatology, Palaeoecology.  ISSN 0031-0182.  463, s 126- 135 . doi: 10.1016/j.palaeo.2016.09.023
• Millett, JM; Wilkins, AD; Campbell, E; Hole, MJ; Taylor, RA; Healy, D; Jerram, Dougal Alexander; Jolley, D W; Planke, Sverre; Archer, SG & Blischke, A (2016). The geology of offshore drilling through basalt sequences: Understanding operational complications to improve efficiency. Marine and Petroleum Geology.  ISSN 0264-8172.  77, s 1177- 1192 . doi: 10.1016/j.marpetgeo.2016.08.010
• Spacapan, Juán; Galland, Olivier; Leanza, Hector Armando & Planke, Sverre (2016). Control of strike-slip fault on dyke emplacement and morphology. Journal of the Geological Society.  ISSN 0016-7649.  173(4), s 573- 576 . doi: 10.1144/jgs2015-166
• Aarnes, Ingrid; Planke, Sverre; Trulsvik, Mikal & Svensen, Henrik (2015). Contact metamorphism and thermogenic gas generation in the Vøring and Møre basins, offshore Norway, during the Paleocene-Eocene thermal maximum. Journal of the Geological Society.  ISSN 0016-7649.  172(5), s 588- 598 . doi: 10.1144/jgs2014-098
• Abdelmalak, Mohamed Mansour; Andersen, Torgeir Bjørge; Planke, Sverre; Faleide, Jan Inge; Corfu, Fernando; Tegner, Christian; Shephard, Grace; Zastrozhnov, Dmitry & Myklebust, Reidun (2015). The ocean-continent transition in the mid-Norwegian margin: Insight from seismic data and an onshore Caledonian field analogue. Geology.  ISSN 0091-7613.  43(11), s 1011- 1014 . doi: 10.1130/G37086.1 Vis sammendrag

  ABSTRACT Understanding the structure of the ocean-continent transition (OCT) in passive margins is greatly enhanced by comparison with onshore analogues. The North Atlantic margins and the “fossil” system in the Scandinavian Caledonides show variations along strike between magma-rich and magma-poor margins, but are different in terms of exposure and degree of maturity. They both display the early stages of the Wilson cycle. Seismic reflection data from the mid-Norwegian margin combined with results from Ocean Drilling Program Leg 104 drill core 642E allow for improved subbasalt imaging of the OCT. Below the Seaward- Dipping Reflector (SDR) sequences, vertical and inclined reflections are interpreted as dike feeder systems. High-amplitude reflections with abrupt termination and saucer-shaped ge- ometries are interpreted as sill intrusions, implying the presence of sediments in the transi- tion zone beneath the volcanic sequences. The transitional crust located below the SDR of the mid-Norwegian margin has a well-exposed analogue in the Seve Nappe Complex (SNC). At Sarek (Sweden), hornfelsed sediments are truncated by mafic dike swarms with densi- ties of 70%–80% or more. The magmatic domain extends for at least 800 km along the Caledonides, and probably reached the size of a large igneous province. It developed at ca. 600 Ma on the margin of the Iapetus Ocean, and was probably linked to the magma-poor hyperextended segment in the southern Scandinavian Caledonides. These parts of the SNC represent an onshore analogue to the deeper level of the mid-Norwegian margin, permitting direct observation and sampling and providing an improved understanding, particularly of the deeper levels, of present-day magma-rich margins.

• Jerram, Dougal Alexander; Svensen, Henrik; Planke, Sverre; Polozov, Alexander G. & Torsvik, Trond Helge (2015). The onset of flood volcanism in the north-western part of the Siberian Traps: Explosive volcanism versus effusive lava flows. Palaeogeography, Palaeoclimatology, Palaeoecology.  ISSN 0031-0182.  441(1), s 38- 50 . doi: 10.1016/j.palaeo.2015.04.022
• Mazzini, Adriano; Svensen, Henrik; Planke, Sverre; Forsberg, Carl Fredrik & Tjelta, Terje (2015). Pockmarks and methanogenic carbonates above the giant Troll gas field in the Norwegian North Sea. Marine Geology.  ISSN 0025-3227.  373, s 26- 38 . doi: 10.1016/j.margeo.2015.12.012 Vis sammendrag

  Acoustic imaging has revealed more than 7000 pockmarks on the seafloor above the Troll East gas field in the Norwegian North Sea. We present the first comprehensive study conducted on one of the World's largest pockmark fields complementing the acoustic data with extensive sampling, geochemical and petrographical studies. Specifically, we aimed at detecting possible active seepage still present over this vast area. The pockmarks are present as isolated structures, on average ~ 35 m wide and up to 100 m in size. In addition, smaller satellite pockmarks surround some of the pockmarks. In contrast to the muddy surroundings, parts of the investigated pockmarks contain laterally extensive carbonate deposits or meter sized carbonate blocks. These blocks provide shelter to abundant colonies of benthic megafauna. The carbonate blocks are comprised of micritic Mg-calcite and calcite, micritic aragonite, and botryoidal aragonite. Framboidal pyrite is also commonly present. Carbon isotopic values of the carbonates are 13C-depleted (δ13C as low as − 59.7‰) and with δ18O up to 4.5‰, indicating a methanogenic origin, possibly linked to gas hydrate dissociation. Pore water extracted from shallow cores from the centre and the flanks of the pockmarks show similar Cl and SO4 profiles as the reference cores outside the pockmarks, ruling out active methane seepage. This conclusion is also supported by seafloor video observations that did not reveal any evidence of visual fluid seepage, and by the absence of microbial mats and by the fact that the carbonate blocks are exposed on the seafloor and party oxidized on the surface. We conclude that methane seepage formed this extensive gas field following to gas hydrate dissociation.

Se alle arbeider i Cristin

• Kjøll, Hans Jørgen; Andersen, Torgeir Bjørge; Galland, Olivier; Corfu, Fernando; Labrousse, Loic; Tegner, Christian & Planke, Sverre (2019). Deep section of a Neoproterozoic fossil magma rich rifted margin exposed. Vis sammendrag

  Structures of rifted continental margins are the finite result of active processes when continents rift apart. During the convergent stages of Wilson cycle, remnants of rifted margins may be incorporated into orogens, especially the magma-poor end-member. The magma-rich margins, however, are commonly lost in subduction due to low buoyancy. The understanding of magma-rich margins is therefore mostly based on drill holes and geophysical observations. In this contribution, we explore the temporal evolution and the ambient conditions of a magma-rich rifted margin preserved within the Scandinavian Caledonides. The Scandinavian Dyke Complex was emplaced in a sedimentary basin during the opening of the Iapetus Ocean 615 to 590 million years ago. The dyke complex now constitutes 70-90% of the area and is locally well-preserved despite the complex Caledonian history. Five field seasons in northern Sweden and Norway provide new observations from regional to microscopic scale about the structural geometry, relative timing, and development of the margin. Jadeite in clinopyroxene geothermobarometry, titanium in biotite geothermometry and garnet isopleth modeling show that the ambient pressure and temperature conditions were similar for the entire dyke complex at 0.25 to 0.45 GPa, with contact metamorphic temperatures up to c. 700◦C. Using a photomosaic of a large and well-exposed cliff face we used layers in the metasediments as markers to restore the host-rock back to the pre-dike configuration, allowing us to quantify the average strain accommodated by the dyke swarm. It accommodated for >100% extension and for 27% crustal thickening. From this we infer that the magma influx rate was higher than the tectonic stretching rate, implying that magma was emplaced in a forceful manner, which is also supported by field observations. In the northern part of the study area, high precision dating of magmatic zircon shows that significant partial melting of the sedimentary host-rock, at relatively shallow levels, occurred at 613 ± 1 Ma. This shows that the crust was molten already 6 Ma before the dyke swarm was emplaced at 606 ± 2 Ma. We propose that the locally pervasive partial melting occurred due to high geothermal gradient and introduction of mafic melts in the lower crust. These processes caused a rapid shallowing of the brittle-ductile transition, which thereby significantly reduced the strength of the crust.

• Andersen, Torgeir Bjørge; Jakob, Johannes; Kjøll, Hans Jørgen; Corfu, Fernando; Planke, Sverre; Torsvik, Trond Helge; Tegner, Christian; Labrousse, Loic & Mohn, Geoffroy (2018). The Pre-Caledonian Margin of Baltica: overview and research in progress. Vis sammendrag

  The Caledonian margin of Baltica formed by continental break-up of Rodinia in the Late Proterozoic to Ediacaran. With exception of the dike-swarm near Egersund in SW Norway, the Fennoscandian basement including the autochthonous basement windows along the axis of the mountain belt were little affected by the magmatism associated with the break-up. The distal parts, however, were strongly attenuated, hyper-extended and a 1000 km long segment, intensively intruded by a Large Igneous Province (LIP), the Pre-Caledonian LIP (PC-LIP). Here, we provide glimpses of our work in progress from the vestiges of the margin. More details on several aspects of the margin evolution are presented by co-authors. Here we present a regional model for the pre-Caledonian margin suggesting it was highly complex and included micro-continental sliver(s) and both a hyperextended, magma-poor domain with transition(s) to attenuated embryonic oceanic and magma-rich margin domains. The break-up related PC-LIP magmatism lasted from approximately 615 to 570 Ma, but the most intense activity appears to have been at ~600 Ma. Our ongoing work suggests that the impingement of a mantle plume on the Ediacaran continental lithosphere was associated with a temperature anomaly of ~100oC, causing widespread melting of the asthenosphere and dyke-intrusion of the continental crust and sediments of the margin. We suggest that the pre-Caledonian margin of the Iapetus preserved in the Scandes comprise most of the elements of passive continental margins, and that it probably represents one of the best exposed field analogue for the deeper and least known parts of passive margins.

• Jerram, Dougal Alexander; Svensen, Henrik; Planke, Sverre; Millett, John M; Jones, Morgan Thomas; Augland, Lars Eivind & Abdelmalak, Mansour (2018). Types and styles of volcanism in the North Atlantic Igneous Province: Implications towards understanding their potential climatic impact..
• Jones, Morgan Thomas; Stokke, Ella Wulfsberg; Schultz, Bo; Augland, Lars Eivind; Planke, Sverre; Tegner, Christian; Mather, Tamsin; Percival, Lawrence & Svensen, Henrik (2018). Fur Island in Denmark: A window into Paleocene-Eocene hyperthermals and North Atlantic volcanism.
• Karstens, Jens; Haflidason, Haflidi; Becker, Lukas; Berndt, Christian; Rüpke, Lars Helmuth; Planke, Sverre; Liebetrau, Volker; Schmidt, Mark & Mienert, Jurgen (2018). Correction: Glacigenic sedimentation pulses triggered post-glacial gas hydrate dissociation (Nature Communications DOI: 10.1038/s41467-018-03043-z). Nature Communications.  ISSN 2041-1723.  9(1) . doi: 10.1038/s41467-018-03587-0
• Kjøll, Hans Jørgen; Andersen, Torgeir Bjørge; Tegner, Christian; Labrousse, Loic & Planke, Sverre (2018). A fossil magma-rich margin revealed. Vis sammendrag

  A fossil magma-rich rifted margin revealed Hans Jørgen Kjøll, Torgeir B. Andersen, Christian Tegner, Loic Labrousse and Sverre Planke 1) CEED 2) Aarhus Universite 3) Paris 4) CEED/VBPR The Iapetus opened ~610 Myr ago, when a plume impinged on the lower crust of Baltica and Laurentia. Stretching of the conjoined crystalline crust started in the Neoproteozoic, prior to break-up and provided accommodation for continental and shallow marine syn-rift sediments. An early a-magmatic phase with discrete and localized deformation was followed by pervasive mafic magmatism where dike-emplacement accounted for the majority of the stretching. During the Caledonian orogeny the Baltican margin was thrusted onto Baltica as the Iapetus closed. Now, vestiges of the magma-rich margin resides within nappes from central Sweden to northern Norway. Although, overprinted by Caledonian fabrics, there are localities where pre-Caledonian structures are well-preserved, thereby allowing for detailed studies of deep to intermediate processes at magma-rich rifted margins. We propose the architecture of the magma-rich margin of Baltica and magma-rich rifted margins in general can be studied in the Caledonides. The well-preserved parts of the margin comprise: 1) Parts of a lower crustal magmatic complex w/gabbros and mafic dykes intruding stretched crystalline basement; 2) Strongly stretched and attenuated crystalline basement intruded by mafic dikes; 3) Highly intruded pre- to syn-rift sediments and 4) Extrusive mafic lavas, including pillow basalts, interlayered with metasediments. Together these levels represent a nearly continuous section through a magma-rich rifted margin, with some never-before described levels, such as the lower crustal magmatic complex.

• Svensen, Henrik; Jerram, Dougal Alexander; Polozov, Alexander; Jones, Morgan Thomas; Augland, Lars Eivind & Planke, Sverre (2018). Volcanic causes for the PETM and other past hothouse climates.
• Tegner, Christian; Andersen, Torgeir Bjørge; Kjøll, Hans Jørgen; Brown, Eric L.; Hagen-Peter, Graham; Corfu, Fernando; Planke, Sverre & Torsvik, Trond Helge (2018). The pre-Caledonian Scandinavian Dyke Complex and 600 Ma plate reconstructions of Baltica. Vis sammendrag

  A spectacular dyke complex is surprisingly well preserved along c. 1000 km in the Caledonian nappes of central and northern Scandinavia. This dyke complex was originally emplaced into continental sedimentary basins along the rifted margin of Baltica, it is part of the Central Iapetus Magmatic Province (CIMP), and it has U-Pb ages of 615-590 Ma. To constrain its origin and to potentially guide plate reconstructions of Baltica we: (1) re-visited the dyke complexes of the Ottfjället, Sarek, Kebnekaise, Tornetrask and Indre Troms mountains of Sweden and Norway; (2) produced new and compiled published geochemical data; (3) modeled mantle sources and melting dynamics; and (4) extended reconstructions of the paleo-position of Baltica back to 600 Ma. The compiled dataset includes c. 600 analyses that forms a coherent suite dominated by tholeiitic ferrobasalt, but including alkali basalts in the central portion. The tholeiitic dykes display lateral variations in geochemical enrichment (e.g. delta-Nb, La/Sm(N) and Sr isotopes) in the southern and central portions, grading to more depleted compositions in the north. Our petrological modeling suggests melting of asthenospheric mantle involving at least two source compositions at temperatures elevated about 100 °C above ambient mantle, consistent with melting of a zoned mantle plume originating from a plume generation zone at the core-mantle boundary. If the position of the present plume generation zone in the Pacific can be viewed as stationary back to 600 Ma, we entertain the idea that the Scandinavian Dyke Complex may be used to guide plate reconstructions.

• Andersen, Torgeir Bjørge; Jakob, Johannes; Kjøll, Hans Jørgen; Corfu, Fernando; Planke, Sverre; Torsvik, Trond Helge; Tegner, Christian & Labrousse, Loic (2017). The Pre-Caledonian Margin of Baltica. Vis sammendrag

  The pre-Caledonian margin of Baltica formed by the rifting and eventual continental break-up of Rodinia in the Late Proterozoic to Ediacaran. With exception of the ca. 615 Ma dolerite dike-swarm near Egersund in SW Norway, the Fennoscandian basement including the mostly autochthonous basement windows in western Scandinavia (Lofoten, Western Gneiss Region, etc.) were surprisingly little affected by the rifting and the subsequent magmatism associated with the break-up. The distal parts of the margin, however, were strongly attenuated, hyper-extended and in a more than 1000 km long segment, intensively intruded by a break-up related Large-Igneous Province (LIP), here referred to as the Pre-Caledonian LIP (PC-LIP). In this presentation, we provide glimpses of new results and observations as well as work in progress from a large part of the nappe-stack of Scandinavian Caledonides containing the vestiges of the pre-Caledonian margin. More details on several aspects of the Pre-Caledonian margin evolution are presented by co-workers during this meeting. Based on our recent and some previous work, we propose a regional paleogeography model for the pre-Caledonian passive margin as it evolved from the Ediacaran into the late-Cambrian to the early-Ordovician, when the Iapetus Ocean started closing. We suggest that the distal margin architecture was highly complex and included micro-continental sliver(s) and a hyperextended, magma-poor domain with transition(s) to highly attenuated embryonic oceanic and magma-rich passive margin domains. The break-up related PC-LIP magmatism lasted from approximately 615 to 570 Ma, but the most intense dyke-emplacement appears to have been around 600 Ma. Our ongoing structural and metamorphic petrology studies, combined with geochronology, geochemical analyses and petrological modelling suggest that the impingement of a mantle plume on the Ediacaran continental lithosphere may have been associated with a temperature anomaly of up to 100oC, causing widespread melting of the asthenosphere as well as partial melt-generation in highly attenuated and intensely dike-intruded parts of the continental crust and sediments of the margin. It is our opinion that the pre-Caledonian distal margin rocks of the Iapetus as preserved in nappes of Scandinavian Caledonides preserve most of the elements of wide passive margins, and that it probably represents one of the best exposed field analogue for the deeper and least known parts of passive margins.

• Andersen, Torgeir Bjørge; Jakob, Johannes; Kjøll, Hans Jørgen; Corfu, Fernando; Tegner, Christian; Mohn, Geoffroy; Labrousse, Loic; Planke, Sverre & Abdelmalak, Mohamed Mansour (2017). The Magma-poor and Magma-rich settings; the onshore perspective: The Caledonian case.
• Faleide, Jan Inge; Abdelmalak, Mohamed Mansour; Shephard, Grace; Torsvik, Trond Helge; Gaina, Carmen; Tsikalas, Filippos; Blaich, Olav Antonio; Planke, Sverre & Myklebust, Reidun (2017). Quantification and restoration of pre-drift extension across NE Atlantic conjugate margins.
• Jerram, Dougal Alexander; Svensen, Henrik; Planke, Sverre; Millett, John M & Reynolds, Pete (2017). Sill induced hydrothermal venting: A summary of our current understanding..
• Jones, Morgan Thomas; Augland, Lars Eivind; Shephard, Grace; Burgess, Seth; Eliassen, Gauti; Jerram, Dougal Alexander; Jochmann, Malte; Friis, Bjarki; Planke, Sverre & Svensen, Henrik (2017). Bentonite layers in Svalbard: constraining sources of volcanism, geochronology, and relative plate motions during the Paleogene.
• Kjøll, Hans Jørgen; Andersen, Torgeir Bjørge; Tegner, Christian; Corfu, Fernando & Planke, Sverre (2017). Wilson cycle-kick-off: Constraining the influence of a LIP during the Neoproterozoic evolution of the pre-Caledonian margin of Baltica and Laurentia.
• Mazzini, Adriano; Svensen, Henrik; Forsberg, Carl Fredrik; Linge, Henriette; Lauritzen, Stein-Erik; Haflidason, Haflidi; Hammer, Øyvind; Planke, Sverre & Tjelta, Tor-Inge (2017). A Climatic Trigger for the Giant Troll Pockmark Field in the Northern North Sea. Vis sammendrag

  Pockmarks are seafloor craters usually formed during methane release on continental margins. However, the mechanisms behind their formation and dynamics remain elusive. Here we report detailed investigations on one of the World’s largest pockmark fields located in the Troll region in the northern North Sea. Seafloor investigations show that >7000 pockmarks are present in a ~600 km2 area. A similar density of pockmarks is likely present over a 15,000 km2 region outside our study area. Based on extensive monitoring, coring, geophysical and geochemical analyses, no indications of active gas seepage were found. Still, geochemical data from carbonate blocks collected from these pockmarks indicate a methanogenic origin linked to gas hydrate dissociation and past fluid venting at the seafloor. We have dated the carbonates using the U-Th method in order to constrain the pockmark formation. The carbonates gave an isochron age of 9.59 ± 1.38 ka BP, i.e. belonging to the initial Holocene. Moreover, radiocarbon dating of microfossils in the sediments inside the pockmarks are consistent with the ages derived from the carbonates. Based on pressure and temperature modelling, we show that the last deglaciation could have triggered dissociation of gas hydrates present in the region of the northern part of the Norwegian Channel, causing degassing of 0.26 MtCH4/km2 at the seafloor. Our results stress the importance of external climatic forcing of the dynamics of the seafloor, and the role of the rapid warming following the Younger Dryas in pacing the marine gas hydrate reservoir.

• Millett, J.M.; Haskins, Eric; Thomas, Donald; Jerram, Dougal Alexander; Planke, Sverre; Healy, D; Kück, Jochem; Rossetti, Lucas; Farrell, Natalie & Pierdominici, Simona (2017). Porosity and permeability evolution of vesicular basalt reservoirs with increasing depth: constraints from the Big Island of Hawai'i..
• Pierdominici, Simona; Kueck, Jochem; Millett, J.M.; Planke, Sverre; Jerram, Dougal Alexander; Haskins, Eric & Thomas, Donald (2017). Present-day stress state analysis on the Big Island of Hawaíi, USA..
• Planke, Sverre; Millett, John M; Maharjan, Dwarika; Jerram, Dougal Alexander & Abdelmalak, Mohamed Mansour (2017). 3D seismic imaging of voluminous earliest Eocene buried lava fields and coastal escarpments off mid-Norway..
• Planke, Sverre; Millett, John; Jerram, Dougal Alexander; Senger, Kim; Galland, Olivier; Schmid, Daniel Walter & Myklebust, Reidun (2017). Petroleum exploration in volcanic basins: An overview of the impact of igneous processes and deposits.
• Polozov, Alexander; Planke, Sverre; Svensen, Henrik; Jerram, Dougal Alexander & Looy, Cindy (2017). Burned and buried by the Siberian traps: tree trunks in volcaniclastics and lavas..
• Schmiedel, Tobias; Kjoberg, Sigurd; Planke, Sverre; Magee, Craig; Galland, Olivier; Schofield, Nick; Jackson, Christopher A.-L. & Jerram, Dougal Alexander (2017). Mechanisms of overburden deformation associated with the emplacement of the Tulipan sill, mid-Norwegian margin.
• Schmiedel, Tobias; Kjoberg, Sigurd; Planke, Sverre; Magee, Craig; Galland, Olivier; Schofield, Nick; Jackson, Christopher A.-L. & Jerram, Dougal Alexander (2017). Mechanisms of overburden deformation associated with the emplacement of the Tulipan sill, mid-Norwegian margin.
• Tegner, Christian; Andersen, Torgeir Bjørge; Brown, Eric L.; Corfu, Fernando; Planke, Sverre; Kjøll, Hans Jørgen & Torsvik, Trond Helge (2017). The pre-Caledonian Scandinavian Dyke Complex and 600 Ma plate reconstructions of Baltica. Vis sammendrag

  Magmatism of the first known rifting phase of the North Atlantic Wilson cycle is surprisingly well preserved in the Cale- donian nappes of central and northern Scandinavia. Along c. 1000 km the Särv and Seve Nappes are characterised by spectacular dyke complexes and other intrusive forms origi- nally emplaced into continental sedimentary basins along the rifted margin of Iapetus. We refer to this as the magma-rich segment of the pre-Caledonian margin of Baltica, in contrast to the hyper-extended and magma-poor segment exposed in southern Norway (Andersen et al., Jakob et al., this meeting). In the larger picture the Scandinavian Dyke Complex is part of the Central Iapetus Magmatic Province ( ). The intensity, volume and structure of the Scandinavian Dyke Complex is comparable to that of the present passive margins of the North Atlantic large igneous province (Kjøll et al., this meeting) and U-Pb ages suggest magmatism was short-lived at 610-590 Ma. To constrain the origin of the Scandinavian Dyke Complex and to potentially guide plate reconstructions of Baltica we: (1) re-visited the dyke complexes of the Särv, Sarek, Kebnekaise, Tornetrask and Indre Troms mountains of Sweden and Norway; (2) compiled new and published geochemical data for the entire dyke complex; (3) modeled mantle sources and melting dy- namics; and (4) extended reconstructions of the paleo-position of Baltica back to 600 Ma. Although the appearance of the dykes ranges from garnet amphibolite gneiss to pristine mag- matic intrusions, all bulk rock compositions largely reflect the original magmatic rock. The compiled dataset includes c. 600 analyses that essentially forms a coherent suite dominated by tholeiitic ferrobasalt akin to the North Atlantic large igneous province, but including alkali basalts in the central portion where meta-carbonatite is also reported. A few samples (<30) are significantly contaminated with crust, but most are largely uncontaminated. The tholeiitic dykes display systematic lateral variations over c. 1000 km in trace element compositions suggesting geochem- ical enrichment (e.g. delta-Nb and La/Sm(N) relative to mid- ocean ridge basalt) in the southern and central portions, grad- ing to more depleted compositions in the north. The most enriched tholeiites occur in the central portion that also in- cludes alkali basalts. The lateral geochemical zoning is com- parable to e.g. the North Atlantic large igneous province and around Iceland today. Our petrological modeling suggests melting of asthenospheric mantle involving at least two source compositions at temperatures elevated above ambiant mantle. We therefore speculate that the Scandinavian Dyke Complex formed by melting of a zoned mantle plume originating from a plume generation zone (margins of large low shear-wave velocity provinces) at the core-mantle boundary. If the posi- tion of the present plume generation zone in the Pacific can be viewed as stationary back to 600 Ma, we entertain the idea that the Scandinavian Dyke Complex may be used to guide plate reconstructions.

• Tegner, Christian; Andersen, Torgeir Bjørge; Brown, Eric L.; Corfu, Fernando; Planke, Sverre; Kjøll, Hans Jørgen & Torsvik, Trond Helge (2017). The pre-Caledonian Scandinavian Dyke Complex and 600 Ma plate reconstructions of Baltica.
• van Soelen, Elsbeth Ester; Hasic, Edi; Planke, Sverre; Svensen, Henrik; Sleveland, Arve Rein Nes; Midtkandal, Ivar; Twitchett, Richard & Kürschner, Wolfram Michael (2017). Permian-Triassic palynofacies and chemostratigraphy in a core recovered from central Spitsbergen..
• Andersen, Torgeir Bjørge & Planke, Sverre (2016, 21. september). Detektiver på havbunn: Geologer samler ny kunnskap om kleber og skifer.  Gudbrandsdølen Dagningen. Vis sammendrag

  Dypdykk i fortid: Geologer fra hele Europa har kommet til Gudbrandsdalen for å undersøke bergarter som kan fortelle oss mer om fortiden. Kleber- og skiferforekomstene i Nord- Gudbrandsdal vil gi geologene fra en rekke land ny kunnskap om hvordan de gamle havområdene ble dannet.

• Augland, Lars Eivind; Jones, Morgan Thomas; Planke, Sverre; Svensen, Henrik & Tegner, Christian (2016). Evaluating the provenance of Permian-Triassic and Palaeocene-Eocene ash beds by high precision U-Pb and Lu-Hf isotopic analyses of zircons: linking local sedimentary records to global events.
• Augland, Lars Eivind; Jones, Morgan Thomas; Svensen, Henrik & Planke, Sverre (2016). Improving the geochronology of the North Atlantic Igneous Province. largeigneousprovinces.org.
• Faleide, Jan Inge; Planke, Sverre; Abdelmalak, Mohamed Mansour; Zastrozhnov, Dmitrii; Wong, P.W.; Shephard, Grace; Indrevær, Kjetil; Tsikalas, Filippos; Gabrielsen, Roy Helge; Gernigon, Laurent; Blaich, Olav A. & Myklebust, Reidun (2016). Basin architecture and evolution at NE Atlantic conjugate margins.
• Galland, Olivier; Abdelmalak, Mohamed Mansour; Leanza, Hector Armando; Mourgues, Regis; Planke, Sverre; Scheibert, Julien & Schmiedel, Tobias (2016). Mechanics of Igneous Intrusion Emplacement and implications for Sedimentary Basins.
• Galland, Olivier; Abdelmalak, Mohamed Mansour; Spacapan, Juán; Mourgues, Regis; Leanza, Hector Armando & Planke, Sverre (2016). Are igneous sheet intrusions really mode I elastic fractures?.
• Jones, Morgan Thomas; Augland, Lars Eivind; Burgess, Seth; Eliassen, Gauti; Svensen, Henrik; Jerram, Dougal Alexander; Jochmann, Malte; Friis, Bjarki & Planke, Sverre (2016). Bentonite layers in Svalbard: constraining sources of volcanism, geochronology, and relative plate motions during the Paleocene and Eocene.
• Jones, Morgan Thomas; Augland, Lars Eivind; Svensen, Henrik; Tegner, Christian; Planke, Sverre & Willumsen, Pi Suhr (2016). Volcano-climate interactions during the PETM and U-Pb dating from the Fur Formation, Denmark.
• Jones, Morgan Thomas; Augland, Lars Eivind; Tegner, Christian; Planke, Sverre; Jerram, Dougal Alexander; Callegaro, Sara; Schultz, Bo & Svensen, Henrik (2016). Volcano-climate interactions during the Paleocene-Eocene Thermal Maximum: Assessing the impact of the North Atlantic Igneous Province from the Fur Formation, Denmark.
• Kjoberg, Sigurd; Schmiedel, Tobias; Planke, Sverre; Svensen, Henrik; Galland, Olivier & Jerram, Dougal Alexander (2016). 3D structure and formation of hydrothermal vent complexes in the Møre Basin.
• Kjøll, Hans Jørgen; Andersen, Torgeir Bjørge; Tegner, Christian; Corfu, Fernando & Planke, Sverre (2016). Wilson-cycle “kick-off”: Constraining the influence of a Large Igneous Province during the Neoproterozoic evolution of the pre-Caledonian margin of Baltica.
• Planke, Sverre; Polteau, S; Senger, Kim; Svensen, Henrik; Faleide, Jan Inge; Myklebust, Reidun & Tegner, Christian (2016). HALIP Intrusive and Extrusive Complexes of Svalbard and the Barents Sea.
• Planke, Sverre; Zuchuat, Valentin; Svensen, Henrik; Hammer, Øyvind; Braathen, Alvar; Silkoset, Petter; Midtkandal, Ivar; Nagy, Jenø; Kürschner, Wolfram Michael; van Soelen, Elsbeth Ester; Faleide, Jan Inge; Augland, Lars Eivind; Jones, Morgan Thomas; Jerram, Dougal Alexander; Franeck, Franziska; Sassier, Caroline; Domeier, Mathew; Twitchett, Richard J.; Jochmann, Malte; Zayoncheck, Andrey; Haflidason, Haflidi; Buckley, Simon John; Kurz, Tobias Herbert; Olaussen, Snorre; Mørk, Atle; Løvø, Vigdis & Lie, Jan Erik (2016). Coring and High-Resolution Imaging of the Permian-Triassic Boundary in Deltadalen, Svalbard.
• Senger, Kim; Planke, Sverre & Galland, Olivier (2016). Igneous intrusions and the petroleum system: from the Arctic to Argentina.
• Tegner, Christian; Andersen, Torgeir Bjørge; Corfu, Fernando; Planke, Sverre; Kjøll, Hans Jørgen & Torsvik, Trond Helge (2016). The pre-Caledonian Large Igneous Province and the North Atlantic Wilson Cycle.
• van Soelen, Elsbeth Ester; Planke, Sverre; Svensen, Henrik; Twitchett, Richard; Polozov, Alexander G. & Kürschner, Wolfram Michael (2016). Chemo- and palyno-stratigraphy of the Permian-Triassic transition in the Boreal region.
• van Soelen, Elsbeth Ester; Planke, Sverre; Svensen, Henrik; Twitchett, Richard; Polozov, Alexander G. & Kürschner, Wolfram Michael (2016). Chemo- and palyno-stratigraphy of the Permian-Triassic transition in the Boreal region. Geophysical Research Abstracts.  ISSN 1029-7006.
• Abdelmalak, Mohamed Mansour; Planke, Sverre; Andersen, Torgeir Bjørge; Faleide, Jan Inge; Corfu, Fernando; Tegner, Christian & Myklebust, Reidun (2015). The Continent-Ocean Transition in the Mid-Norwegian Margin: Insight From Seismic Data and the Onshore Caledonian Analogue in the Seve Nappe Complex. Vis sammendrag

  The continental breakup and initial seafloor spreading in the NE Atlantic was accompanied by widespread intrusive and extrusive magmatism and the formation of conjugate volcanic passive margins. These margins are characterized by the presence of seaward dipping reflectors (SDR), an intense network of mafic sheet intrusions of the continental crust and adjacent sedimentary basins and a high-velocity lower crustal body. Nevertheless many issues remain unclear regarding the structure of volcanic passive margins; in particular the transitional crust located beneath the SDR.New and reprocessed seismic reflection data on the Mid-Norwegian margin allow a better sub-basalt imaging of the transitional crust located beneath the SDR. Different high-amplitude reflections with abrupt termination and saucer shaped geometries are identified and interpreted as sill intrusions. Other near vertical and inclined reflections are interpreted as dykes or dyke swarms. We have mapped the extent of the dyke reflections along the volcanic margin. The mapping suggests that the dykes represent the main feeder system for the SDR. The identification of saucer shaped sills implies the presence of sediments in the transitional zone beneath the volcanic sequences. Onshore exposures of Precambrian basement of the eroded volcanic margin in East Greenland show that, locally, the transitional crust is highly intruded by dykes and intrusive complexes with an increasing intensity of the plumbing and dilatation of the continental crust ocean-ward. Another well exposed analogue for a continent-ocean transitional crust is located within the Seve Nappe Complex (SNC) of the Scandinavian Caledonides. The best-preserved parts of SNC in the Pårte, Sarek, Kebnekaise, Abisko, and Indre Troms mountains are composed mainly of meta-sandstones and shales (now hornfelses) truncated typically by mafic dykes. At Sarek and Pårte, the dykes intrude the sedimentary rocks of the Favoritkammen Group, with a dyke density up to 70-80%. This complex was photographed in a regional helicopter survey and sampled for the study of the different dyke generations, their geochemistry and ages in 2014. Extending for at least 800 km within the SNC, the mafic igneous rocks most probably belonged to a volcanic system with the size of a large igneous province (LIP). This volcanic margin is suggested to have formed along the Caledonian margin of Baltica or within hyperextended continental slivers outboard of Baltica during the breakup of Rodinia. The intensity of the pre-Caledonian LIP-magmatism is comparable to that of the NE Atlantic volcanic margins. The SNC-LIP is considered to represent a potential onshore analogue to the deeper level of the Mid-Norwegian margin transitional crust, and permits direct observation, sampling and better understanding of deeper levels of magma-rich margins.

• Andersen, Torgeir Bjørge; Alsaif, Manar; Corfu, Fernando; Jakob, Johannes; Planke, Sverre & Tegner, Christian (2015). Magma-poor and magma-rich segments along the hyperextended, pre-Caledonian passive margin of Baltica. Vis sammendrag

  The Scandinavian Caledonides constitute a more than 1850 km long ‘Himalayan-type’ orogen, formed by collision between Baltica-Avalonia and Laurentia. Subduction-related magmatism in the Iapetus ended at ⇠430 Ma and continental convergence continued for ⇠30 Myr until ⇠400 Ma. The collision produced a thick orogenic wedge comprising the stacked remnants of the rifted to hyperextended passive Baltican margin (Andersen et al. 2012), as well as suspect, composite and outboard terranes, which were successively emplaced as large-scale nappe complexes onto Baltica during the Scandian collision (see Corfu et al. 2014 for a recent review). Large parts (⇠800 km) of the mountain-belt in central Scandinavia, particularly in the Särv and Seve Nappes and their counterparts in Troms, are characterised by spectacular dyke complexes emplaced into continental sediments (e.g. Svenningsen 2001, Hollocher et al. 2007). These constitute a magma-rich segment formed along the margin of Baltica or within hyperextended continental slivers outboard of Baltica. The intensity of the pre-Caledonian magmatism is comparable to that of the present NE-Atlantic and other volcanic passive margins. The volumes and available U-Pb ages of 610-597 Ma (Baird et al. 2014 and refs therein) suggest that the magmatism was short lived, intense and therefore compatible with a large igneous province (LIP). By analogy with present-day margins this LIP may have been associated with continental break-up and onset of sea-floor spreading. The remnants of the passive margin both north and south of the magma-rich segment have different architectures, and are almost devoid of rift/drift related magmatic rocks. Instead, these magma-poor segments are dominated by heterogeneous sediment-filled basins characterised by the abundant presence of solitary bodies of variably altered mantle peridotites, also commonly present as detrital serpentinites. These basins are interpreted to have formed by hyperextension. We suggest that the pre-Caledonian margin of Baltica underwent hyperextension until break-up, which was associated with emplacement of a LIP at ⇠600 Ma in the central segment. Andersen, T.B., Labrousse, L., Corfu, F. and Osmundsen, P.T., 2012: Evidence for hyperextension along the pre-Caledonian margin of Baltica. Jl. Geol. Soc. London, 601-612 Baird, G.B., Figg, SA. and Chamberlain, K.R., 2014: Intrusive age and geochemistry of the Kebne Dyke Complex in the Seve Nappe Complex, Kebnekaise Massif, arctic Sweden Caledonides, GFF, doi: 10.1080/11035897.2014.924553 Corfu, F., Andersen, T.B. and Gasser, D., 2014: The Scandinavian Caledonides: main features, conceptual advances and critical questions. Geol. Soc. London Spec. Publ. 390 doi:10.1144/SP390.25 Hollocher. K, Robinson, P., Walsh, E. and Terry M.P., 2007:The Neoproterozoic Ottfjellet dike swarm of the Middle Allochthon, traced geochemically into the hinterland, Western Gneiss Region, Norway. Am. Jl. Sci. 307, 901-953 Svenningsen, O., 2001: Onset of seafloor spreading in the Iapetus Ocean at 608Ma: precise age of the Sarek Dyke Swarm, northern Swedish Caledonides. Precambrian Res., 110, 241–254.

• Corseri, Romain; Senger, Kim; Planke, Sverre; Maharjan, Dwarika & Pedersen, Camilla (2015). Investigation of a mid-crustal conductor in the North Gjallar Ridge, Offshore Norway, inferred from Magnetotelluric data.
• Faleide, Jan Inge; Mahajan, Aatisha; Gabrielsen, Roy Helge; Breivik, Asbjørn Johan; Planke, Sverre & Myklebust, Reidun (2015). Basement and Late Paleozoic basin configurations in the western and central Barents Sea.
• Faleide, Jan Inge; Wong, Po Wan; Gabrielsen, Roy Helge; Tsikalas, Filippos; Blaich, Olav Antonio; Planke, Sverre & Myklebust, Reidun (2015). Basin evolution at the SW Barents Sea margin and its conjugate off NE Greenland.
• Font, Eric; Adatte, Thierry; Planke, Sverre; Svensen, Henrik & Kürschner, Wolfram Michael (2015). Impact, volcanism, global changes, and mass extinction. Palaeogeography, Palaeoclimatology, Palaeoecology.  ISSN 0031-0182.  441, s 1- 3 . doi: 10.1016/j.palaeo.2015.11.001
• Jones, Morgan Thomas; Burgess, Seth; Eliassen, Gauti Trygvason; Svensen, Henrik; Planke, Sverre; Jochmann, Malte & Friis, Bjarki (2015). Arctic volcanism during the Palaeocene and Eocene: The timing and provenance of volcanic ashes in the Central Tertiary Basin, Svalbard.
• Jones, Morgan Thomas; Eliassen, Gauti Trygvason; Burgess, Seth; Augland, Lars Eivind; Svensen, Henrik; Planke, Sverre; Jochmann, Malte & Friis, Bjarki (2015). Palaeocene-Eocene volcanism in the Arctic: Basin development and continental breakup constrained by ash layers in Svalbard.
• Jones, Morgan Thomas; Jerram, Dougal Alexander; Svensen, Henrik; Planke, Sverre; Grove, Clayton & Gislason, Sigurdur R. (2015). The effects of large igneous provinces on the global carbon and sulphur cycles: understanding the sources and the sinks..
• Jones, Morgan Thomas; Svensen, Henrik; Tegner, Christian; Planke, Sverre & Willumsen, Pi Suhr (2015). Large volcanic eruptions and the PETM: Geochemistry from the Fur Formation, Denmark.
• Midtkandal, Ivar; Faleide, Jan Inge; Planke, Sverre; Myrsini, Dimitriou; Dahlberg, Maria E.; Myklebust, Reidun; Nystuen, Johan Petter & Torsvik, Trond Helge (2015). Source-to-sink Dynamics in the Early Cretaceous Boreal Basin; Progradational Lobes from a Missing Source.

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