Olivier Galland

• Palma, J. Octavio; Burchardt, Steffi; Schmiedel, Tobias; Guerriero, Lucas; Jerram, Dougal Alexander & Mair, Karen [Vis alle 8 forfattere av denne artikkelen] (2024). Stratigraphy and structure of Chachahuén volcanic complex, southern Mendoza province, Argentina. Journal of South American Earth Sciences. ISSN 0895-9811. 140. doi: 10.1016/j.jsames.2024.104900.
• Greiner, Sonja H.M.; Burchardt, Steffi; Sigmundsson, Freysteinn; Óskarsson, Birgir V.; Galland, Olivier & Geirsson, Halldór [Vis alle 7 forfattere av denne artikkelen] (2023). Interaction between propagating basaltic dikes and pre-existing fractures: A case study in hyaloclastite from Dyrfjöll, Iceland. Journal of Volcanology and Geothermal Research. ISSN 0377-0273. 442. doi: 10.1016/j.jvolgeores.2023.107891.
• Rabbel, Ole; Hasenclever, Jörg; Galerne, Christophe Yann; Galland, Olivier; Mair, Karen & Palma, Octavio (2023). Impact of permeability evolution in igneous sills on hydrothermal flow and hydrocarbon transport in volcanic sedimentary basins. Solid Earth (SE). ISSN 1869-9510. 14(6), s. 625–646. doi: 10.5194/se-14-625-2023. Fulltekst i vitenarkiv
• Galland, Olivier; Villar, Héctor J.; Mescua, José; Jerram, Dougal Alexander; Midtkandal, Ivar & Palma, J. Octavio [Vis alle 8 forfattere av denne artikkelen] (2023). The long-term legacy of subvolcanic intrusions on fluid migration in sedimentary basins: The Cerro Alquitrán case study, northern Neuquén Basin, Argentina. Basin Research. ISSN 0950-091X. 35(5), s. 1840–1855. doi: 10.1111/bre.12782. Fulltekst i vitenarkiv
• Sæter, Torstein; Galland, Olivier; Feneuil, Blandine; Haugen, Håvard Jostein & Carlson, Andreas (2023). Growth of a viscoplastic blister underneath an elastic sheet. Journal of Fluid Mechanics. ISSN 0022-1120. 964, s. 1–16. doi: 10.1017/jfm.2023.320. Fulltekst i vitenarkiv
• Reutz, Elisabeth Hoffstad & Galland, Olivier (2022). The effect of weak Mohr–Coulomb layers on the onset of caldera collapse - A limit analysis modelling approach. Journal of Volcanology and Geothermal Research. ISSN 0377-0273. 433. doi: 10.1016/j.jvolgeores.2022.107727. Fulltekst i vitenarkiv
• Senger, Kim & Galland, Olivier (2022). Stratigraphic and Spatial Extent of HALIP Magmatism in Central Spitsbergen. Geochemistry Geophysics Geosystems. ISSN 1525-2027. 23(11). doi: 10.1029/2021GC010300. Fulltekst i vitenarkiv Vis sammendrag

  Rapid extensive magmatism may have a profound effect on global climate by liberating and releasing greenhouse gases to the atmosphere through contact metamorphism of lithologically heterogeneous host rocks and degassing of magma and associated lava flows. The high Arctic Archipelago of Svalbard offers accessible, superbly exposed outcrops revealing Early Cretaceous magmatism associated with the High Arctic Large Igneous Province (HALIP). In this contribution, we investigate the onshore-offshore intrusive complex of central Spitsbergen formed due to HALIP activity, that is, the Diabasodden Suite. This is the most “data-rich” part of Svalbard due to past petroleum exploration and research drilling. In this area, the predominantly dolerite intrusions are emplaced in a range of host rocks ranging from Permian carbonate-dominated successions to organic-rich shale-dominated successions of Middle Triassic and Late Jurassic-Early Cretaceous age. Two hundred sixty five individual igneous intrusions, covering 72 km2, are exposed onshore in the study area. This equates to approximately 0.14–2.5 km3 of emplaced magma. In addition, subsurface characterization using borehole, seismic and magnetic data indicates that an area of additional ca. 3,000 km2 is affected by magmatism (magma volume 3.2–195.2 km3). Wireline logs in boreholes characterize both intrusions and associated aureoles. Aureoles with very low resistivity indicate occurrence of organic-rich shales suggesting past fluid circulation and de-gassing. This study forms the foundation for quantifying HALIP-related magmatism in the data-poorer parts of Svalbard, and other circum-Arctic basins.

• Lescoutre, Rodolphe; Almqvist, Bjarne; Koyi, Hemin; Berthet, Théo; Hedin, Peter & Galland, Olivier [Vis alle 9 forfattere av denne artikkelen] (2022). Large-scale, flat-lying mafic intrusions in the Baltican crust and their influence on basement deformation during the Caledonian orogeny. Geological Society of America Bulletin. ISSN 0016-7606. 134(11-12), s. 3022–3048. doi: 10.1130/B36202.1. Fulltekst i vitenarkiv
• Rincón, M.; Márquez, A.; Herrera, R.; Galland, Olivier; Sánchez-Oro, J. & Concha, D. [Vis alle 7 forfattere av denne artikkelen] (2022). Monitoring Volcanic and Tectonic Sandbox Analogue Models Using the Kinect v2 Sensor. Earth and Space Science. ISSN 2333-5084. 9(6). doi: 10.1029/2020EA001368. Fulltekst i vitenarkiv
• Galland, Olivier; de la Cal, Hernán; Mescua, José & Rabbel, Ole (2022). 3-dimensional trapdoor structure of laccolith-induced doming and implications for laccolith emplacement, Pampa Amarilla, Mendoza Province, Argentina. Tectonophysics. ISSN 0040-1951. 836. doi: 10.1016/j.tecto.2022.229418.
• Poppe, Sam; Holohan, Eoghan P.; Rudolf, Michael; Rosenau, Matthias; Galland, Olivier & Delcamp, Audray [Vis alle 7 forfattere av denne artikkelen] (2021). Mechanical properties of quartz sand and gypsum powder (plaster) mixtures: Implications for laboratory model analogues for the Earth's upper crust. Tectonophysics. ISSN 0040-1951. 814. doi: 10.1016/j.tecto.2021.228976.
• Mattsson, Tobias; Petri, Benoît; Almqvist, Bjarne S.G.; McCarthy, William; Burchardt, Steffi & Palma, Octavio [Vis alle 8 forfattere av denne artikkelen] (2021). Decrypting Magnetic Fabrics (AMS, AARM, AIRM) Through the Analysis of Mineral Shape Fabrics and Distribution Anisotropy. Journal of Geophysical Research (JGR): Solid Earth. ISSN 2169-9313. 126(6). doi: 10.1029/2021JB021895. Fulltekst i vitenarkiv
• Schmiedel, Tobias; Burchardt, Steffi; Mattsson, Tobias; Guldstrand, Frank Bo Buster; Galland, Olivier & Palma, Octavio [Vis alle 7 forfattere av denne artikkelen] (2021). Emplacement and Segment Geometry of Large, High-Viscosity Magmatic Sheets. Minerals. ISSN 2075-163X. 11(10). doi: 10.3390/min11101113. Fulltekst i vitenarkiv Vis sammendrag

  Understanding magma transport in sheet intrusions is crucial to interpreting volcanic unrest. Studies of dyke emplacement and geometry focus predominantly on low-viscosity, mafic dykes. Here, we present an in-depth study of two high-viscosity dykes (106 Pa·s) in the Chachahuén volcano, Argentina, the Great Dyke and the Sosa Dyke. To quantify dyke geometries, magma flow indicators, and magma viscosity, we combine photogrammetry, microstructural analysis, igneous petrology, Fourier-Transform-Infrared-Spectroscopy, and Anisotropy of Magnetic Susceptibility (AMS). Our results show that the dykes consist of 3 to 8 mappable segments up to 2 km long. Segments often end in a bifurcation, and segment tips are predominantly oval, but elliptical tips occur in the outermost segments of the Great Dyke. Furthermore, variations in host rocks have no observable impact on dyke geometry. AMS fabrics and other flow indicators in the Sosa Dyke show lateral magma flow in contrast to the vertical flow suggested by the segment geometries. A comparison with segment geometries of low-viscosity dykes shows that our high-viscosity dykes follow the same geometrical trend. In fact, the data compilation supports that dyke segment and tip geometries reflect different stages in dyke emplacement, questioning the current usage for final sheet geometries as proxies for emplacement mechanism.

• Rabbel, Ole; Palma, Octavio; Mair, Karen; Galland, Olivier; Spacapan, Juan Bautista & Senger, Kim (2021). Fracture networks in shale-hosted igneous intrusions: Processes, distribution and implications for igneous petroleum systems. Journal of Structural Geology. ISSN 0191-8141. 150. doi: 10.1016/j.jsg.2021.104403. Fulltekst i vitenarkiv
• Bertelsen, Håvard Svanes; Guldstrand, Frank Bo Buster; Sigmundsson, Freysteinn; Pedersen, Rikke; Mair, Karen & Galland, Olivier (2021). Beyond elasticity: Are Coulomb properties of the Earth's crust important for volcano geodesy? Journal of Volcanology and Geothermal Research. ISSN 0377-0273. 410. doi: 10.1016/j.jvolgeores.2020.107153.
• Sleveland, Arve; Midtkandal, Ivar; Galland, Olivier & Leanza, Hector Armando (2020). Sedimentary Architecture of Storm-Influenced Tidal Flat Deposits of the Upper Mulichinco Formation, Neuquén Basin, Argentina. Frontiers in Earth Sciences. ISSN 1863-4621. 8. doi: 10.3389/feart.2020.00219. Fulltekst i vitenarkiv
• Pierdominici, Simona; Millet, John M.; Kück, Jochem K. M.; Thomas, Donald; Jerram, Dougal Alexander & Planke, Sverre [Vis alle 9 forfattere av denne artikkelen] (2020). Stress Field Interactions Between Overlapping Shield Volcanoes: Borehole Breakout Evidence From the Island of Hawai'i, USA. Journal of Geophysical Research (JGR): Earth Surface. ISSN 2169-9003. 125(8). doi: 10.1029/2020JB019768. Fulltekst i vitenarkiv
• Poppe, Sam; Galland, Olivier; de Winter, N. J.; Goderis, S.; Claeys, P. & Debaille, V. [Vis alle 8 forfattere av denne artikkelen] (2020). Structural and Geochemical Interactions Between Magma and Sedimentary Host Rock: The Hovedøya Case, Oslo Rift, Norway. Geochemistry Geophysics Geosystems. ISSN 1525-2027. 21(3). doi: 10.1029/2019GC008685. Fulltekst i vitenarkiv
• Rabbel, Ole; Mair, Karen; Galland, Olivier; Grühser, Carina & Meier, Tobias (2020). Numerical Modeling of Fracture Network Evolution in Organic‐Rich Shale With Rapid Internal Fluid Generation. Journal of Geophysical Research (JGR): Solid Earth. ISSN 2169-9313. 125. doi: 10.1029/2020JB019445. Fulltekst i vitenarkiv
• Senger, Kim; Betlem, Peter; Birchall, Thomas; Buckley, Simon John; Coakley, Bernard & Eide, Christian Haug [Vis alle 23 forfattere av denne artikkelen] (2020). Using digital outcrops to make the high Arctic more accessible through the Svalbox database. Journal of Geoscience Education (JGE). ISSN 1089-9995. doi: 10.1080/10899995.2020.1813865. Vis sammendrag

  The high Arctic is a remote place, where geoscientific research and teaching require expensive and logistically demanding expeditions to make use of the short field seasons. The absence of vegetation facilitates the use of modern photogrammetric techniques for the cost-effective generation of high-resolution digital outcrop models (DOMs). These georeferenced models can be used in pre-fieldwork activities to help prepare for traditional geological fieldwork, during fieldwork to record observations, and post-fieldwork to conduct quantitative geological analyses. Analyses of DOMs range in scale from mm-cm (e.g., size and spacing of dinosaur footprints), to hundreds of meters (e.g., seismic modeling of outcrops and outcrop-well-seismic correlations) and can advance research objectives. This integration is strengthened if key geoscientific data, like geological and topographical maps, subsurface profiles, borehole data, remote sensing data, geophysical data and DOMs can be integrated through a common database, such as the Svalbox database that we present in this commentary. Svalbox geographically targets the Svalbard archipelago, where fieldwork is challenging due to the harsh polar environment, risk of polar bear encounters and demanding transport to the field area. The University Centre in Svalbard nonetheless relies on utilizing the natural Svalbard environment for its field-based education, and now makes use of Svalbox to make geological fieldwork more efficient and post-fieldwork analyses more quantitative. Experience and usage of such tools in geoscientific education, particularly in the polar regions, is not well documented. Therefore, we share experiences on both developing and optimizing Svalbox, and on student and lecturer usage. Svalbox includes a web-based interface through which DOMs are shared and displayed together with relevant public-domain geoscientific data sets. Svalbox also serves as a platform to share student and teacher experiences on the entire DOM workflow, from acquisition to data distribution. For the Svalbox users questioned by the project group, DOMs were found to provide many benefits, including quantitative analyses, extended field season, appreciation of scale and data sharing that significantly outweigh present-day challenges, such as the need for expensive hardware and lack of easily accessible interpretation software, the latter being surmountable within the near-term

• Burchardt, Steffi; Mattsson, Tobias; Palma, J Octavio; Galland, Olivier; Almqvist, Bjarne & Mair, Karen [Vis alle 9 forfattere av denne artikkelen] (2019). Progressive Growth of the Cerro Bayo Cryptodome, Chachahuen Volcano, Argentina?Implications for Viscous Magma Emplacement. Journal of Geophysical Research (JGR): Solid Earth. ISSN 2169-9313. 124(8), s. 7934–7961. doi: 10.1029/2019JB017543.
• Souche, Alban; Galland, Olivier; Haug, Øystein Thorden & Dabrowski, Marcin (2019). Impact of host rock heterogeneity on failure around pressurized conduits: Implications for finger-shaped magmatic intrusions. Tectonophysics. ISSN 0040-1951. 765, s. 52–63. doi: 10.1016/j.tecto.2019.05.016. Fulltekst i vitenarkiv
• Galland, Olivier; Spacapan, Juan Bautista; Rabbel, Ole; Mair, Karen; Soto, Frederico Gonzalez & Eiken, Trond [Vis alle 8 forfattere av denne artikkelen] (2019). Structure, emplacement mechanism and magma-flow significance of igneous fingers ? Implications for sill emplacement in sedimentary basins. Journal of Structural Geology. ISSN 0191-8141. 124, s. 120–135. doi: 10.1016/j.jsg.2019.04.013. Fulltekst i vitenarkiv
• Poppe, Sam; Holohan, Eoghan; Galland, Olivier; Buls, Nico; Van Gompel, Gert & Keelson, Benyameen [Vis alle 11 forfattere av denne artikkelen] (2019). An inside perspective on magma intrusion: Quantifying 3d displacement and strain in laboratory experiments by dynamic X-ray computed tomography. Frontiers in Earth Science. ISSN 2296-6463. 7. doi: 10.3389/feart.2019.00062. Fulltekst i vitenarkiv
• Spacapan, Juan Bautista; D'Odorico, Alejandro; Palma, Octavio; Galland, Olivier; Senger, Kim & Ruiz, Remigio [Vis alle 8 forfattere av denne artikkelen] (2019). Low resistivity zones at contacts of igneous intrusions emplaced in organic-rich formations and their implications on fluid flow and petroleum systems: a case study in the northern Neuquén Basin, Argentina. Basin Research. ISSN 0950-091X. 32(1), s. 3–24. doi: 10.1111/bre.12363. Fulltekst i vitenarkiv
• Kjøll, Hans Jørgen; Galland, Olivier; Labrousse, Loic & Andersen, Torgeir Bjørge (2019). Emplacement mechanisms of a dyke swarm across the brittle-ductile transition and the geodynamic implications for magma-rich margins. Earth and Planetary Science Letters. ISSN 0012-821X. 518, s. 223–235. doi: 10.1016/j.epsl.2019.04.016. Fulltekst i vitenarkiv Vis sammendrag

  gneous dykes are the main magma transport pathways through the Earth’s crust, and they are considered to mainly accommodate for tectonic extension in volcanic rifts. Dykes are typically considered to result from brittle fracturing, even in the ductile crust. A common assumption is that dyke orientation is controlled by tectonic stresses, such that dykes in rifts are expected to be vertical and perpendicular to extension. Here we report on detailed field observations of a spectacularly well-exposed dyke swarm to show that dykes were not systematically emplaced by purely brittle processes and that dyke orientation may differ from the dominant tectonic stress orientations. The dyke complex formed near the brittle-ductile transition during opening of the Iapetus Ocean and is now exposed in the Scandinavian Caledonides. Distinct dyke morphologies related to different emplacement mechanisms has been recognized: 1) Brittle dykes that exhibit straight contacts with the host rock, sharp tips, en-echelon segments with bridges exhibiting angular fragments; 2) Brittle-ductile dykes that exhibit undulating contacts, rounded tips, ductile folding in the host rock and contemporaneous brittle and ductile features;3) Ductile “dykes” that exhibit rounded shapes and mingling between the soft ductile host rock and the intruding mafic magma. The brittle dykes exhibit two distinct orientations separated by c. 30◦ that are mutually cross-cutting, suggesting that the dyke swam did not consist of only vertical sheets perpendicular to regional extension, as expected in rifts. We were able to use the well-exposed host rock layers as markers to perform a kinematic restoration to quantify the average strain accommodating the emplacement of the dyke complex: it accommodated for >100% extension, but counter-intuitively it also accommodated for 27% crustal thickening. We infer that the magma influx rate was higher than the tectonic stretching rate, implying that magma was emplaced forcefully, as supported by field observations. Finally, our observations suggest that the fast emplacement of the dyke swarm triggered a rapid shallowing of the brittle-ductile transition, and lead to a considerable weakening of the crust. Our study can potentially have large implications significant for surface topography and seismicity in active rifts and volcanic areas around the world.

• Schmiedel, Tobias; Galland, Olivier; Haug, Øystein Thorden; Dumazer, Guillaume Henri & Breitkreuz, Christoph (2019). Coulomb failure of Earth's brittle crust controls growth, emplacement and shapes of igneous sills, saucer-shaped sills and laccoliths. Earth and Planetary Science Letters. ISSN 0012-821X. 510, s. 161–172. doi: 10.1016/j.epsl.2019.01.011. Fulltekst i vitenarkiv
• Galland, Olivier; Bertelsen, Håvard Svanes; Eide, Christian Haug; Guldstrand, Frank Bo Buster; Haug, Øystein Thorden & Leanza, Hector Armando [Vis alle 14 forfattere av denne artikkelen] (2018). Storage and Transport of Magma in the Layered Crust—Formation of Sills and Related Flat-Lying Intrusions. I Burchardt, Steffi (Red.), Volcanic and Igneous Plumbing Systems - Understanding Magma Transport, Storage, and Evolution in the Earth's Crust. Elsevier. ISSN 978-0-12-809749-6. s. 113–138. doi: 10.1016/B978-0-12-809749-6.00005-4. 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.

• Planke, Sverre; Rabbel, Ole; Galland, Olivier; Millet, John; Manson, Ben & Jerram, Dougal Alexander [Vis alle 8 forfattere av denne artikkelen] (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. I Vernengo, Luis; Atencio, Mario; Branca, Marcela; Corti, Eduardo; D'Biassi, Tomás; Dario Enrique, Jorge; García Torrejón, Maximiliano; Pianelli, Luis; Ricardi, Alberto; Soubiés, Daniel & Späth, Federico (Red.), 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. ISSN 978-987-9139-92-9. s. 343–366.
• Galland, Olivier; Schmiedel, Tobias; Bertelsen, Håvard Svanes; Guldstrand, Frank Bo Buster; Haug, Øystein Thorden & Souche, Alban (2018). Geomechanical modeling of fracturing and damage induced by igneous intrusions: Implications for fluid flow in volcanic basins. I Sánchez, Martín; Frydman, Marcelo & Hryb, Damian (Red.), 10 Congreso de Exploración y Desarrollo de Hidrocarburos - Sesión de Geomecánica: Eficiencia a innovación a través de la geomecánica el la exploración y desarrollo de reservorios. Instituto Argentino del Petrole y del Gas. ISSN 978-987-9139-87-5. s. 101–120.
• Bertelsen, Håvard Svanes; Rogers, Benjamin David; Galland, Olivier; Dumazer, Guillaume Henri & Benanni, Alexandre Abbana (2018). Laboratory Modeling of Coeval Brittle and Ductile Deformation During Magma Emplacement Into Viscoelastic Rocks. Frontiers in Earth Science. ISSN 2296-6463. 6, s. 1–16. doi: 10.3389/feart.2018.00199. Fulltekst i vitenarkiv
• Spacapan, Juan Bautista; Palma, J.O.; Rocha, Emilio; Leanza, Hector Armando; D'odorico, Alejandro & Rojas Vera, Emilio A [Vis alle 10 forfattere av denne artikkelen] (2018). Maturation of the Vaca Muerta and Agrio formations due to the emplacement of magmatic intrusive complexes in the southern Mendoza Region of the Neuquen Basin. Revista de la Asociación Geológica Argentina (RAGA). ISSN 0004-4822. 75(2), s. 199–209.
• Magee, Craig; Muirhead, James; Schofield, Nick; Walker, Richard J.; Galland, Olivier & Holford, Simon [Vis alle 9 forfattere av denne artikkelen] (2018). Structural signatures of igneous sheet intrusion propagation. Journal of Structural Geology. ISSN 0191-8141. doi: 10.1016/j.jsg.2018.07.010.
• Haug, Øystein Thorden; Galland, Olivier; Souloumiac, Pauline; Souche, Alban; Guldstrand, Frank Bo Buster & Schmiedel, Tobias [Vis alle 7 forfattere av denne artikkelen] (2018). Shear Versus Tensile Failure Mechanisms Induced by Sill Intrusions: Implications for Emplacement of Conical and Saucer-Shaped Intrusions. Journal of Geophysical Research (JGR): Solid Earth. ISSN 2169-9313. 123(5), s. 3430–3449. doi: 10.1002/2017JB015196. Fulltekst i vitenarkiv
• Spacapan, Juan Bautista; Palma, J.O.; Galland, Olivier; Manceda, Rene; Rocha, E & D'Odorico, A. [Vis alle 7 forfattere av denne artikkelen] (2018). Thermal impact of igneous sill-complexes on organic-rich formations and implications for petroleum systems: A case study in the northern Neuquen Basin, Argentina. Marine and Petroleum Geology. ISSN 0264-8172. 91, s. 519–531. doi: 10.1016/j.marpetgeo.2018.01.018.
• Guldstrand, Frank Bo Buster; Galland, Olivier; Hallot, Erwan & Burchardt, Steffi (2018). Experimental Constraints on Forecasting the Location of Volcanic Eruptions from Pre-eruptive Surface Deformation. Frontiers in Earth Science. ISSN 2296-6463. 6. doi: 10.3389/feart.2018.00007. Fulltekst i vitenarkiv
• Rabbel, Ole; Galland, Olivier; Mair, Karen; Lecomte, Isabelle; Senger, Kim & Spacapan, Juan Bautista [Vis alle 7 forfattere av denne artikkelen] (2018). From field analogues to realistic seismic modelling: a case study of an oil-producing andesitic sill complex in the Neuquén Basin, Argentina. Journal of the Geological Society. ISSN 0016-7649. 175(4), s. 580–593. doi: 10.1144/jgs2017-116. Fulltekst i vitenarkiv Vis sammendrag

  Interpretation of seismic data has played a major role in recent advances in the studies of igneous sill complexes. Seismic modelling studies based on field analogues represent a promising tool to close the scale gap between observations from outcrops and seismic data and support seismic interpretation. Virtual outcrop models are commonly used to include highresolution geological structures in models of seismic-scale field analogues. However, realistic seismic modelling requires not only detailed structural input, but also well-constrained elastic properties and an adequate seismic modelling technique. Here, we present a seismic modelling study of oil-producing andesitic sills in the Neuquén Basin, Argentina, which implements all modelling elements at high accuracy by combining virtual outcrop models, well data and a 2(3)D filtering method. Our results indicate that the modelled seismic signatures of intrusive bodies observed in field analogues are characterized by frequencydependent interference and strong amplitude variations owing to highly variable elastic properties of both host rock and sills. We demonstrate that detailed waveform patterns observed in real seismic data can be linked to intrusive bodies below the traditionally assumed limit of resolution via realistic seismic modelling. This illustrates how an integrated modelling approach based on field analogues can aid seismic interpretation.

• Eriksen, Jon Alm; Toussaint, Renaud; Måløy, Knut Jørgen; Flekkøy, Eirik Grude; Galland, Olivier & Sandnes, Bjørnar (2018). Pattern formation of frictional fingers in a gravitational potential. Physical Review Fluids. ISSN 2469-990X. 3(1). doi: 10.1103/PhysRevFluids.3.013801. Fulltekst i vitenarkiv
• Girod, Luc Maurice Ramuntcho; Nuth, Christopher; Kääb, Andreas; McNabb, Robert Whitfield & Galland, Olivier (2017). MMASTER: Improved ASTER DEMs for elevation change monitoring. Remote Sensing. ISSN 2072-4292. 9(7). doi: 10.3390/rs9070704. Fulltekst i vitenarkiv
• Schmiedel, Tobias; Kjoberg, Sigurd; Planke, Sverre; Magee, Craig; Galland, Olivier & Schofield, Nick [Vis alle 8 forfattere av denne artikkelen] (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.

• Haug, Øystein Thorden; Galland, Olivier; Souloumiac, Pauline; Souche, Alban Jean-Rene; Guldstrand, Frank Bo Buster & Schmiedel, Tobias (2017). Inelastic damage as a mechanical precursor for the emplacement of saucer-shaped intrusions. Geology. ISSN 0091-7613. 45(12), s. 1099–1102. doi: 10.1130/G39361.1.
• Guldstrand, Frank Bo Buster; Burchardt, Steffi; Hallot, E & Galland, Olivier (2017). Dynamics of Surface Deformation Induced by Dikes and Cone Sheets in a Cohesive Coulomb Brittle Crust. Journal of Geophysical Research (JGR): Solid Earth. ISSN 2169-9313. 122(10), s. 8511–8524. doi: 10.1002/2017JB014346. Fulltekst i vitenarkiv
• Schmiedel, Tobias; Galland, Olivier & Breitkreuz, Christoph (2017). Dynamics of Sill and Laccolith Emplacement in the Brittle Crust: Role of Host Rock Strength and Deformation Mode. Journal of Geophysical Research (JGR): Solid Earth. ISSN 2169-9313. 122(11), s. 8860–8871. doi: 10.1002/2017JB014468. Fulltekst i vitenarkiv Vis sammendrag

  Igneous intrusions in sedimentary basins exhibit a great diversity of shapes from thin sheets (e.g. sills, cone sheets), to massive intrusions (e.g. laccoliths, plugs). Presently, none of the established models of magma emplacement have the capability to simulate this diversity because they account for either purely elastic or purely plastic or purely viscous host rocks, whereas natural rocks are complex elasto-plastic materials. In this study, we investigate the effects of elasto-plastic properties of host rock on magma emplacement using laboratory experiments made of dry granular materials of variable cohesion. Our results show how the deformation mechanism of the host rock controls the emplacement of magma: thin sheet sills form in high-cohesion materials, which dominantly deform by elastic bending, whereas massive intrusions such as punched laccoliths form in low-cohesion materials, which dominantly deform by shear failure. Our models also suggest that combined elastic/shear failure deformation modes likely control the emplacement of cone sheets. Our experiments are the first to spontaneously produce diverse, geologically relevant intrusion shapes. Our models show that accounting for the elasto-plastic behaviour of the host rock is essential to filling the gap between the established elastic and plastic models of magma emplacement, and so to reveal the dynamics of magma emplacement in the Earth's brittle crust.

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• Senger, Kim & Galland, Olivier (2022). Early Cretaceous magmatism in central Spitsbergen: stratigraphic and spatial exten.
• Rabbel, Ole; Galland, Olivier; Mair, Karen; Lecomte, Isabelle; Spacapan, Juan Bautista & Palma, Octavio (2020). Integration of geological field observations and geophysical data: The El Manzano Sill Complex (Argentina) as a showcase of igneous intrusions emplaced in active petroleum systems.
• Kjøll, Hans Jørgen; Galland, Olivier; Labrousse, Loic & Andersen, Torgeir Bjørge (2020). Emplacement Mechanisms of a Dyke Swarm Across the Brittle-Ductile Transition.
• Kjøll, Hans Jørgen; Galland, Olivier; Labrousse, Loic & Andersen, Torgeir Bjørge (2020). Emplacement mechanisms of a dyke swarm across the Brittle- Ductile transition. Vis sammendrag

  Dykes are the main magma transport pathways through the Earth’s crust and, in volcanic rifts, they are considered the main mechanism to accommodate tectonic extension. Most models consider dykes as hydro-fractures propagating as brittle tensile, mode I cracks opening perpendicular to the least principal stress. This implies that dykes emplaced in rifts are expected to be sub-vertical and accommodate crustal extension. Here we present detailed field observations of a well-exposed dyke swarm that formed near the brittle-ductile transition at a magma-rich rifted margin during opening of the Iapetus Ocean. It was related to a ca 600 million year-old large igneous province. Our observations show that dykes were not systematically emplaced by purely brittle deformation and that dyke orientation may differ from the typical mode 1 pattern. Distinct dyke morphologies related to different emplacement mechanisms have been recognized including: 1) Brittle dykes that exhibit straight contacts with the host rock, sharp tips, and en-echelon segments with bridges exhibiting angular fragments; 2) Brittle-ductile dykes with undulating contacts, rounded tips, folding of the host rock and contemporaneous brittle and ductile features; 3) Ductile “dykes” with rounded shapes and mingling between partially molten host rock and the intruding mafic magma. The brittle dykes exhibit two distinct orientations separated by ~30° that are mutually cross-cutting, demonstrating that the dyke swam did not consist of only vertical sheets oriented perpendicular to regional extension, as expected in rifts. By using the host-rock layers as markers, a kinematic restoration to quantify the average strain accommodating the emplacement of the dyke complex was performed. This strain estimate shows that the dyke swarm accommodated >100% horizontal extension, but also 27% vertical thickening. This suggests that the magma influx rate was higher than the tectonic stretching rate, which imply that magma was emplaced forcefully, as supported by field observations of the host-rock deformation. Finally, observations of typical “brittle” dykes that were subsequently deformed by ductile mechanisms as well as dykes that were emplaced by purely ductile mechanisms suggest that the fast emplacement of the dyke swarm triggered a rapid shallowing of the brittle-ductile transition. The abrupt dyke emplacement and associated heating resulted in weakening of the crust that probably facilitated the continental break-up, which culminated with opening of the Iapetus Ocean.

• Galland, Olivier (2020). Farlige vulkaner i verden. [Radio]. NRK.
• Galland, Olivier (2019). Volcanology laboratory practicals for students at the French school in Oslo.
• Galland, Olivier & Sassier, Caroline (2019). Cover page photograph of magazine GeoExPro. GeoExpro. ISSN 1744-8743. 16(4), s. 1–1.
• Galland, Olivier & Sassier, Caroline (2019). Photograph on cover page of the magazine GeoExPro. GeoExpro. ISSN 1744-8743. 16(4), s. 1–1.
• Galland, Olivier (2019). Geology guide for French school.
• Souche, Alban; Galland, Olivier; Haug, Øystein Thorden & Dabrowski, Marcin (2019). Impact of host rock heterogeneity on failure around pressurized conduits: Implications for finger-shaped magmatic intrusions.
• Schmiedel, Tobias; Galland, Olivier; Haug, Øystein Thorden; Dumazer, Guillaume & Breitkreuz, Christoph (2019). Coulomb failure of Earth’s brittle crust controls growth, emplacement and shapes of igneous sills, saucer-shaped sills and laccoliths .
• Poppe, Sam; Holohan, Eoghan; Galland, Olivier & Kervyn, Matthieu (2019). Magma-induced deformation of the Earth’s upper crust in nature and in laboratory experiments scanned by X-ray Computed Tomography.
• Mattsson, Tobias; Burchardt, Steffi; Palma, Octavio; Galland, Olivier; Almqvist, Bjarne S.G. & Hammer, Øyvind [Vis alle 9 forfattere av denne artikkelen] (2019). Magmatic fabrics related to different growth stages of the Cerro Bayo Cryptodome.
• Haug, Øystein Thorden; Galland, Olivier; Souloumiac, Pauline; Souche, Alban; Guldstrand, Frank Bo Buster & Schmiedel, Tobias [Vis alle 7 forfattere av denne artikkelen] (2019). Shear versus tensile failure mechanisms induced by sill intrusions – Implications for emplacement of conical and saucer-shaped intrusions.
• Galland, Olivier; de la Cal, Hernán & Rabbel, Ole (2019). Laccolith-induced deformation – A case study integrating field mapping, 3D seismic and well data at Pampa Amarilla, Neuquén Basin, Argentina.
• Bertelsen, Håvard Svanes; Galland, Olivier; Rogers, Benjamin David; Dumazer, Guillaume Henri & Abbana Benanni, Alexandre (2019). Laboratory modeling of coeval brittle and ductile deformation during magma emplacement into viscoelastic rocks.
• Galland, Olivier (2019). The Physical Geology of Subvolcanic Systems – Laccoliths, Sills and Dykes (LASI6).
• Kjøll, Hans Jørgen; Galland, Olivier; Labrousse, Loic & Andersen, Torgeir Bjørge (2019). Emplacement Mechanisms of a Dyke Swarm Across the Brittle-Ductile Transition.
• Guldstrand, Frank Bo Buster; Bertelsen, Håvard Svanes; Souche, Alban; Galland, Olivier & Zanella, Alain (2019). Intrusion of Viscous Magma in a Cohesive Crust Visualized and Quantified from Quasi-2D Laboratory Experiments.
• Guldstrand, Frank Bo Buster; Galland, Olivier & Mair, Karen (2019). Learning-by-doing in the laboratory.
• Rabbel, Ole; Galland, Olivier; Palma, Octavio; Spacapan, Juan Bautista; Senger, Kim & Lecomte, Isabelle [Vis alle 7 forfattere av denne artikkelen] (2019). From field observations to seismic modeling: The El Manzano Sill Complex (Argentina) as a showcase of the influence of igneous intrusions on petroleum systems .
• Måløy, Knut Jørgen; Eriksen, Jon Alm; Flekkøy, Eirik Grude; Toussaint, Renaud; Galland, Olivier & Sandnes, Bjørnar (2019). Pattern formation of frictional fingers in a gravitational field.
• Måløy, Knut Jørgen; Eriksen, Jon Alm; Flekkøy, Eirik Grude; Toussaint, Renaud; Galland, Olivier & Sandnes, Bjørnar (2019). Pattern formation of frictional fingers in a gravitational potential.
• Sleveland, Arve; Midtkandal, Ivar; Galland, Olivier & Leanza, Hector Armando (2019). Sedimentary architecture of mixed-process mouth bar deposits in the Mulichinco Formation, Neuquén Basin, Argentina.
• Sleveland, Arve; Midtkandal, Ivar; Galland, Olivier & Leanza, Hector Armando (2019). Compensational stacking and architecture of mouth-bar deposits in a mixed-process deltaic environment; Mulichinco Formation, Neuquén Basin, Argentina.
• Senger, Kim; Betlem, Peter; Rabbel, Ole; Galland, Olivier & Lecomte, Isabelle (2019). Early Cretaceous igneous intrusions in Svalbard: seismic modelling as a link between boreholes, outcrops and seismic data.
• Kjøll, Hans Jørgen; Andersen, Torgeir Bjørge; Labrousse, Loic & Galland, Olivier (2019). From rift to drift - Construction of the magma-rich pre-Caledonian Iapetus margin of Baltica. Vis sammendrag

  The northern part of the pre-Caledonian Iapetus margin, which now rests within nappes in the Scandinavian Caledonides, is generally characterized as a fossil magma-rich rifted margin. The margin developed in the late Ediacaran during the opening of the Iapetus Ocean. It was deformed and metamorphosed during the Caledonian orogeny, but large parts of the margin escaped the penetrative strain and regional metamorphism related to this event, and are now preserved in kilometer-scale boudins. The boudins preserve a several kilometer-thick sedimentary package mostly composed of siliciclastic and carbonaceous rocks. A key unit in the stratigraphy is a stromatolite-bearing dolomitic marble containing pure magnesite lenses as well as Cl-rich scapolite, both indicative of evaporite deposits. This unit can be found at several localities along the Scandinavian Caledonides. A recently described glaciogenic diamictite directly overlies the carbonates, which in turn is overlain by a > 1 km thick shallow marine sandstone succession, possibly marking the onset of rifting. The youngest detrital zircon from the sandstone unit is 698 Ma, providing a useful maximum deposition age. The sedimentary succession rests on top of a basement slice with top-W extensional shear indicators. The deformation has been dated to 637 Ma and corroborates the interpretation that Baltica and Laurentia was rifting at this time. The entire sedimentary succession is dissected by a dense network of mafic dikes, which has been dated to range from 596-608 Ma, providing a minimum estimate for the deposition of the sedimentary succession. This minimum age also rules out the Gaskiers glacial event to be responsible for the deposition of the diamictite. The emplacement of the dike swarm was short and intense and led to local partial melting of the host rocks. The rapid influx of magma exceeded the tectonic stretching rate, which together with their conjugate geometry allowed the dike emplacement to also cause a vertical thickening of the crust synchronous with extension. The diking event led to the break-up of Baltica and Laurentia in the Late Ediacaran after at least 30 million years of rifting and show that the magmatic event started late in the overall rifting history.

• Mair, Karen; Bertelsen, Håvard Svanes; Guldstrand, Frank Bo Buster & Galland, Olivier (2019). Learning by doing: Use of research based methods and novel laboratory experiments in teaching Earthquake and Volcanic Processes.
• Kjøll, Hans Jørgen; Andersen, Torgeir Bjørge; Galland, Olivier; Corfu, Fernando; Labrousse, Loic & Tegner, Christian [Vis alle 7 forfattere av denne artikkelen] (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.

• Kjøll, Hans Jørgen; Galland, Olivier; Labrousse, Loic & Andersen, Torgeir Bjørge (2019). Dyke emplacement mechanisms across the brittle-ductile transition. Vis sammendrag

  Dyke emplacement mechanisms across the brittle-ductile transition Hans Jørgen Kjøll1, Olivier Galland2, Loic Labrousse3 & Torgeir Andersen1 1 Center for Earth Evolution and Dynamics (CEED), University of Oslo 2 Physics of Geological Processes, the Njord Center, Department of Geosciences, University of Oslo 3 Institut des Sciences de la Terre Paris, ISTeP, CNRS-INSU, Sorbonne Université Dyking is the main process of magma transport through the Earth’s lithosphere. Dykes are thin sheets exhibiting shapes similar to fractures, so that the main models of dyke emplacement assume that they form by mode I hydraulic fracturing following the σ1-σ2 plane. Because of the rapid strain rates accommodating dyking, it is assumed that dyke propagation and emplacement are only governed by brittle processes, even in the ductile crust. However, the contribution of ductile deformation in dyke emplacement has not been assessed. Here we report detailed and spectacular field observations from northern Sweden and Norway of a ~605 Ma old dyke complex emplaced near the brittle-ductile transition. The dyke complex formed during continental rifting and opening of the Iapetus Ocean, and is now exposed in the Scandinavian Caledonides. In northern Sweden, observations are made along a 1.5 km long continuously exposed cliff providing unique and exceptional overview images of the dyke complex. The detailed structural analysis of the dykes and of the structures related to their emplacement allows us to identify distinct dyke emplacement mechanisms, sub-divided into: 1) Brittle dykes that exhibit straight contacts with the host rock, sharp tips, en-echelon segments with either broken bridges or intact bridges between the segments. The dyke thicknesses follow a Weibull distribution, commonly applied to fracture mechanics; 2) Brittle-ductile dykes that exhibit ductile bridges with complex patterns. Both brittle-ductile and ductile-brittle features are observed, i.e. where ductile flow induced by inflating dykes overprint brittle structures associated with dyke emplacement and vice versa; 3) Ductile “dykes” that show mingling textures between the soft ductile host rock and the intruding mafic magma as well as irregular magmatic boudinage. The dykes exhibit two distinct orientations, and are mutually cross-cutting, suggesting that the dykes did not form as vertical sheets perpendicular to regional extension. Thanks to the well-exposed layering of the dykes’ host rock, we performed a kinematic restoration to quantify the strain induced by the dyke complex. As expected, the dyke complex accommodated >100% extension in agreement with the rifting. However, counter-intuitively it also accommodated 12% of crustal thickening, in agreement with local shortening structures near the dyke walls, showing the forceful mechanism of magma emplacement. Our observations underline the complexity of magma emplacement mechanisms near the brittle-ductile transition and show that dyke emplacement cannot be described as simple mode-I brittle fractures that are being passively filled and inflated by magma.

• Galland, Olivier (2018). The impacts of igneous intrusions on the Vaca Muerta Fm., Neuquén Basin, Argentina.
• Galland, Olivier; Bertelsen, Håvard Svanes; Guldstrand, Frank Bo Buster; Schmiedel, Tobias; Rogers, Benjamin David & Souche, Alban [Vis alle 8 forfattere av denne artikkelen] (2018). Are geodetic models physically relevant for understanding magma transport processes?
• Galland, Olivier & Sassier, Caroline (2018). The Puna Plateau: Treasures behind desolation. GeoExpro. ISSN 1744-8743. 15(4), s. 34–37.
• Galland, Olivier; Bertelsen, Håvard Svanes; Guldstrand, Frank Bo Buster; Haug, Øystein Thorden; Souche, Alban & Schmiedel, Tobias (2018). Geomechanical modeling of fracturing and damage induced by Igneous Intrusions: implications for fluid flow in volcanic basins.
• Guldstrand, Frank Bo Buster; Galland, Olivier; Souche, Alban; Bertelsen, Håvard Svanes & Zanella, Alain (2018). Dyke induced Quasi-2D deformation in a Coulomb brittle host – the influence of host strength on propagation and emplacement.
• Schmiedel, Tobias & Galland, Olivier (2018). Dynamics of sub-volcanic systems in sedimentary basins and related mechanisms of host rock deformation.
• Schmiedel, Tobias & Galland, Olivier (2018). Dynamics of sub-volcanic systems in sedimentary basins and related mechanisms of host rock deformation.
• Schmiedel, Tobias & Galland, Olivier (2018). Dynamics of sub-volcanic systems in sedimentary basins and related mechanisms of host rock deformation.
• Schmiedel, Tobias & Galland, Olivier (2018). Dynamics of sub-volcanic systems in sedimentary basins and related mechanisms of host rock deformation.
• Galland, Olivier (2018). NRK - Nyhetsmorgen - Forkser Galland om volkanutbrudd. [Radio]. NRK - Oslo.
• Sleveland, Arve Rein Nes; Galland, Olivier; Leanza, Hector Armando & Midtkandal, Ivar (2018). Architecture of mixed-process mouth-bar deposits; compensational stacking in the Mulichinco Formation, Neuquén Basin, Argentina.
• Rabbel, Ole; Galland, Olivier; Mair, Karen; Lecomte, Isabelle & Spacapan, Juan Bautista (2018). Improving seismic interpretation of igneous sill complexes via seismic modelling. Vis sammendrag

  Seismic interpretation has been playing a key role in establishing the role of igneous sill complexes emplaced in organic-rich sediments on global climate change throughout geological history (e.g., Svensen et al. 2004, Aarnes et al. 2015): the heat brought by the sills to their organic-rich host leads to massive thermogenic generation of greenhouse gases (e.g., CO2, CH4), eventually catastrophically released to the atmosphere. Robust volume estimates of these greenhouse gases rely on robust estimates of magma volumes of the sill complexes, which require confident mapping of subsurface sill intrusions. Large sills are easy to map in seismic data, because they create strong property contrasts, which cause high amplitude reflections. However, igneous sills vary strongly in thickness and up to 88 percent of the sills may be missing in the interpretation, since their thickness is below the seismic resolution limit (Schofield et al. 2015). In this presentation, we present seismic modelling study designed to characterize typical seismic signatures (splitting, stepping, braided reflections) of thin intrusions, and to indicate potential ways to infer the shapes of thin intrusions in the seismic interpretation. Due to their anomalously high vp/vs ratio, intrusions cause a characteristic amplitude-vs-offset (AVO) response with high AVO intercept and gradient. Thus, we will highlight the great potential of using seismic pre-stack and offset data for the interpretation of thin intrusions. Our results indicate how seismic interpretation and thereby volume estimates of sill complexes can be significantly improved using data of relevant quality.

• Haug, Øystein Thorden; Galland, Olivier; Souloumiac, Pauline; Souche, Alban Jean-Rene; Guldstrand, Frank Bo Buster & Schmiedel, Tobias (2018). A new model for saucer-shaped intrusions: Shear failure versus tensile opening at sill tips. Vis sammendrag

  Sills with a characteristic saucer shape are common features in many sedimentary basins worldwide. Previous models of sill emplacement usually assume that pure elastic bending of the overburden of growing sills control their evolution to saucer shape. However, field observations show that significant shear damage also accommodate sill emplacement. To which extent such damage plays an active role on sill emplacement or not is not understood. To address this, we study the condition for shear failure and the distribution of damage in the overburden of sills using the limit analysis software Optum G2. Through a parameter study, we investigate the effect of the length-to-depth ratio (L/D) of the sill, the cohesion of the host rock and the emplacement depth on the over-pressure within the sill at failure. The results show that the characteristic saucer shape is ubiquitously reproduced using this approach (Haug et al, 2017). The over-pressure required for shear failure scales linearly with the host cohesion and as a power-law of L/D. From these observations, we propose a scaling law for a new shear failure criterion in the overburden of a sill. We compare our scaling law to an analytical solution of hydrofractures, and show that tensile tip propagation is favored for small sills, but overburden shear failure may become favorable for large sills. From these results, we suggest that sills initially grow laterally by tensile propagation until reaching a critical L*, when the overburden fails in shear, leading to the emplacement of saucer-shaped sill’s inclined sheets.

• Schmiedel, Tobias; Galland, Olivier; Haug, Øystein Thorden & Breitkreuz, Christoph (2018). How do sills become laccoliths? An answer from integrated laboratory and numerical modelling. Vis sammendrag

  Igneous intrusions in the upper brittle crust exhibit diverse shapes ranging from thin sheets (dykes, sills, cone sheets), to thick, massive intrusions (laccoliths, plutons, plugs). Presently, none of the established models of magma emplacement have the capability to simulate this diversity because they account for end member rheology of the host rocks (elastic, viscous or plastic), whereas natural rocks are complex elasto-plastic materials. We investigated the effects of host rock rheology on magma emplacement using scaled laboratory models. The model rocks were dry Coulomb granular materials of variable strength (cohesion). We show that strong (high-cohesion) host rock, results in the emplacement of thin, sheet intrusions (sills, cone sheets). Conversely, weak (low-cohesion) host rock results in the emplacement of massive intrusions (laccoliths, plugs). We integrate our laboratory results with numerical simulations to constrain the host rock deformation mechanism that accommodates magma emplacement in the experiments. Our results show how both sills and laccoliths result from initial thin sills that spread horizontally until triggering shear failure of the overburden at a critical radius. Two scenarios can then happen: (1) the overburden is cohesive enough and allows space opening in the sub-surface to accommodate viscous magma inflow along the failure planes, so sills evolve as sheets (saucer shape or cone sheets), or (2) the overburden is not cohesive enough and does not allow sub-surface space opening to accommodate viscous magma inflow along the failure planes, so the sill inflates and lifts up the overburden along shear zones to form a massive laccolith.

• Guldstrand, Frank Bo Buster & Galland, Olivier (2017). Dynamic Surface Deformation due to Dykes and Cone Sheets in a Cohesive Coulomb Brittle Crust.
• Galland, Olivier (2017). Current research in Neuquén Basin - Oslo Volcanic Plumbing Systems group.
• Galland, Olivier (2017). Modelling structures induced by magma emplacement in sedimentary basins.
• Bertelsen, Håvard Svanes; Guldstrand, Frank Bo Buster & Galland, Olivier (2017). Dyke tip processes and large-scale deformation: implications for geodetic modelling.
• Galland, Olivier; Bertelsen, Håvard Svanes; Guldstrand, Frank Bo Buster; Girod, Luc Maurice Ramuntcho; Johannessen, Rikke F. & Bjugger, Fanny [Vis alle 8 forfattere av denne artikkelen] (2017). Application of open-source photogrammetric software MicMac for geodetic monitoring in laboratory models.
• Michail, Maria; Coltorti, Massimo; Gianolla, Piero; Riva, Alberto; Rosenau, Matthias & Bonadiman, Costanza [Vis alle 11 forfattere av denne artikkelen] (2017). Analogue modeling on interaction between shallow magma intrusion and a strike-slip fault: Application on the middle Triassic Monzoni Intrusive Complex (Dolomites, Italy). Vis sammendrag

  The southwestern part of the Dolomites in Northern Italy has undergone a short-lived Ladinian (Middle Triassic) tectono-magmatic event, forming a series of significant magmatic features. These intrusive bodies deformed and metamorphosed the Permo-Triassic carbonate sedimentary framework. In this study we focus on the tectonomagmatic evolution of the shallow shoshonitic Monzoni Intrusive Complex of this Ladinian event (ca 237 Ma), covering an area of 20 km^2. This NW-SE elongated intrusive structure (5 km length) shows an orogenic magmatic affinity which is in contrast to the tectonic regime at the time of intrusion. Strain analysis shows anorogenic transtensional displacement in accordance with the ENE-WSW extensional pattern in the central Dolomites during the Ladinian. Field interpretations led to a detailed description of the regional stratigraphic sequence and the structural features of the study area. However, the geodynamic context of this magmatism and the influence of the inherited strike-slip fault on the intrusion, are still in question. To better understand the specific natural prototype and the general mechanisms of magma emplacement in tectonically active areas, we performed analogue experiments defined by, but not limited to, first order field observations. We have conducted a systematic series of experiments in different tectonic regimes (static conditions, strike-slip, transtension). We varied the ratio of viscous to brittle stresses between magma and country rock, by injecting Newtonian fluids both of high and low viscosity (i.e. silicone oil/vegetable oil) into granular materials of varying cohesion (sand, silica flour, glass beads). The evolving surface and side view of the experiments were monitored by photogrammetric techniques for strain analyses and topographic evolution. In our case, the combination of the results from field and analogue experiments brings new insights regarding the tectonic regime, the geometry of the intrusive body, and the deformational pattern of the evolving system.

• Galland, Olivier (2017). Exploring volcanoes' roots - A journey to Patagonia and... Blindern's basement.
• Galland, Olivier (2017). Natural fracture characterisation in intrusive systems, Neuquén Basin, Argentina.
• Bertelsen, Håvard Svanes; Guldstrand, Frank Bo Buster & Galland, Olivier (2017). Dike tip processes and large-scale deformation: implication for geodetic modelling.
• Schmiedel, Tobias; Galland, Olivier & Breitkreuz, Christoph (2017). The control of host rock strength on sill and laccolith emplacement: insights from quantitative laboratory models.
• Rogers, Benjamin David; Bertelsen, Håvard Svanes & Galland, Olivier (2017). Magma intrusion in viscoelastic media: laboratory model of coeval brittle and ductile deformation.
• Burchardt, Steffi; Palma, Octavio; Galland, Olivier; Mair, Karen & Jerram, Dougal Alexander (2017). Syn-emplacement deformation of the Cerro Bayo laccolith, Argentina.
• Poppe, Sam; Galland, Olivier; Buls, Nico; Holohan, Eoghan; Rosenau, Matthias & Mourgues, Regis [Vis alle 7 forfattere av denne artikkelen] (2017). An unusual patient: 4D X-ray computed tomography of analogue magma intrusion experiments.

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