Magnetotellurisk Analyse for Grønland og Postglasial Isostatisk Evolusjon (MAGPIE)

• Weerdesteijn, Maaike Francine Maria; Naliboff, John B.; Conrad, Clinton Phillips; Reusen, Jesse M.; Steffen, Rebekka & Heister, Timo [Vis alle 7 forfattere av denne artikkelen] (2023). Modeling Viscoelastic Solid Earth Deformation Due To Ice Age and Contemporary Glacial Mass Changes in ASPECT. Geochemistry Geophysics Geosystems. ISSN 1525-2027. 24(3). doi: 10.1029/2022GC010813. Fulltekst i vitenarkiv
• Paul, Jyotirmoy; Conrad, Clinton Phillips; Becker, Thorsten W. & Ghosh, Attreyee (2023). Convective Self-Compression of Cratons and the Stabilization of Old Lithosphere. Geophysical Research Letters. ISSN 0094-8276. 50(4). doi: 10.1029/2022GL101842. Fulltekst i vitenarkiv
• Ramirez, Florence Dela Cruz; Conrad, Clinton Phillips & Selway, Katherine (2023). Grain size reduction by plug flow in the wet oceanic upper mantle explains the asthenosphere's low seismic Q zone. Earth and Planetary Science Letters. ISSN 0012-821X. 616. doi: 10.1016/j.epsl.2023.118232. Fulltekst i vitenarkiv
• Marcilly, Chloe M.; Torsvik, Trond Helge & Conrad, Clinton Phillips (2022). Global Phanerozoic sea levels from paleogeographic flooding maps. Gondwana Research. ISSN 1342-937X. 110, s. 128–142. doi: 10.1016/j.gr.2022.05.011. Fulltekst i vitenarkiv
• Heyn, Björn Holger & Conrad, Clinton Phillips (2022). On the Relation Between Basal Erosion of the Lithosphere and Surface Heat Flux for Continental Plume Tracks . Geophysical Research Letters. ISSN 0094-8276. 49(7). doi: 10.1029/2022GL098003. Fulltekst i vitenarkiv Vis sammendrag

  While hotspot tracks beneath thin oceanic lithosphere are visible as volcanic island chains, the plume-lithosphere interaction for thick continental or cratonic lithosphere often remains hidden due to the lack of volcanism. To identify plume tracks with missing volcanism, we characterize the amplitude and timing of surface heat flux anomalies following a plume-lithosphere interaction using mantle convection models. Our numerical results confirm an analytical relationship in which surface heat flux increases with the extent of lithosphere thinning, which is primarily controlled by the viscosity structure of the lower lithosphere and the asthenosphere. We find that lithosphere thinning is greatest when the plate is above the plume conduit, while the maximum heat flux anomaly occurs about 40-140 Myr later. Therefore, younger continental and cratonic plume tracks can be identified by observed lithosphere thinning, and older tracks by an increased surface heat flux, even if they lack extrusive magmatism.

• Weerdesteijn, Maaike Francine Maria; Conrad, Clinton Phillips & Naliboff, John B. (2022). Solid Earth Uplift Due To Contemporary Ice Melt Above Low-Viscosity Regions of the Upper Mantle. Geophysical Research Letters. ISSN 0094-8276. 49(17). doi: 10.1029/2022GL099731. Fulltekst i vitenarkiv Vis sammendrag

  Glacial isostatic adjustment explains topographic change in formerly and currently glaciated regions, but the role of small (∼100s km) regions of unusually low-viscosity mantle is poorly understood. We developed viscoelastic models with low-viscosity regions in the upper mantle, and measured the effect of these regions on solid earth uplift resulting from contemporary surface ice melt. We found viscous uplift occurring on decadal timescales above the low-viscosity region, at rates comparable to or larger than those from elastic uplift or the viscous response to ice age melting. We find that uplift rates are sensitive to the location, dimensions, and viscosity of the low-viscosity region, and that the largest uncertainty in uplift rates likely comes from the low-viscosity region's horizontal extent. Rapid viscous ground uplift can impact ice dynamics if the low-viscosity region is located close to an ice sheet margin, as for Antarctica and Greenland.

• Ramirez, Florence Dela Cruz; Selway, Katherine; Conrad, Clinton Phillips & Lithgow-Bertelloni, C. (2022). Constraining Upper Mantle Viscosity Using Temperature and Water Content Inferred From Seismic and Magnetotelluric Data. Journal of Geophysical Research (JGR): Solid Earth. ISSN 2169-9313. 127(8). doi: 10.1029/2021JB023824. Fulltekst i vitenarkiv
• Sames, Benjamin; Wagreich, Michael; Conrad, Clinton Phillips & Iqbal, S. (2020). Aquifer-eustasy as the main driver of short-term sea-level fluctuations during Cretaceous hothouse climate phases. Geological Society Special Publication. ISSN 0305-8719. 498, s. 9–38. doi: 10.1144/SP498-2019-105. Fulltekst i vitenarkiv Vis sammendrag

  A review of short-term (<3 myr: c. 100 kyr to 2.4 myr) Cretaceous sea-level fluctuations of several tens of metres indicates recent fundamental progress in understanding the underlying mechanisms for eustasy, both in timing and in correlation. Cretaceous third- and fourth-order hothouse sea-level changes, the sequence-stratigraphic framework, are linked to Milankovitch-type climate cycles, especially the longer-period sequence-building bands of 405 kyr and 1.2 myr. In the absence of continental ice sheets during Cretaceous hothouse phases (e.g. Cenomanian–Turonian), growing evidence indicates groundwater-related sea-level cycles: (1) the existence of Milankovitch-type humid-arid climate oscillations, proven via intense humid weathering records during times of regression and sea-level lowstands; (2) missing or inverse relationships of sea-level and the marine δ18O archives, i.e. the lack of a pronounced positive excursion, cooling signal during sea-level lowstands; and (3) the anti-phase relationship of sea and lake levels, attesting to high groundwater levels and charged continental aquifers during sea-level lowstands. This substantiates the aquifer-eustasy hypothesis. Rates of aquifer-eustatic sea-level change remain hard to decipher; however, reconstructions range from a very conservative minimum estimate of 0.04 mm a−1 (longer time intervals) to 0.7 mm a−1 (shorter, probably asymmetric cycles). Remarkably, aquifer-eustasy is recognized as a significant component for the Anthropocene sea-level budget.

• Hartmann, Robert; Ebbing, Jörg & Conrad, Clinton Phillips (2020). A Multiple 1D Earth Approach (M1DEA) to account for lateral viscosity variations in solutions of the sea level equation: An application for glacial isostatic adjustment by Antarctic deglaciation. Journal of Geodynamics. ISSN 0264-3707. 135. doi: 10.1016/j.jog.2020.101695. Fulltekst i vitenarkiv Vis sammendrag

  The pseudo-spectral form of the sea level equation (SLE) requires the approximation of a radially-symmetric visco-elastic Earth. Thus, the resulting predictions of sea level change (SLC) and glacial isostatic adjustment (GIA) often ignore lateral variations in the Earth structure. Here, we assess the capabilities of a Multiple 1D Earth Approach (M1DEA) applied to large-scale ice load components with different Earth structures to account for these variations. In this approach the total SLC and GIA responses result from the superposition of individual responses from each load component, each computed globally assuming locally-appropriate 1D Earth structures. We apply the M1DEA to three separate regions (East Antarctica, West Antarctica, and outside Antarctica) to analyze uplift rates for a range of Earth structures and different ice loads at various distances. We find that the uplift response is mostly sensitive to the local Earth structure, which supports the usefulness of the M1DEA. However, stresses transmitted across rheological boundaries (e.g., producing peripheral bulges) present challenges for the M1DEA, but can be minimized under two conditions: (1) If the considered time period of ice loading for each component is consistent with the relaxation time of the local Earth structure. (2) If the load components can be subdivided according to the scale of the lateral variations in Earth structure. Overall, our results indicate that M1DEA could be a computationally much cheaper alternative to 3D finite element models, but further work is needed to quantify the relative accuracy of both methods for different resolutions, loads, and Earth structure variations.

• Smith-Johnsen, Silje; de Fleurian, Basile; Schlegel, Nicole; Seroussi, Hélène & Nisancioglu, Kerim Hestnes (2020). Exceptionally high heat flux needed to sustain the Northeast Greenland Ice Stream. The Cryosphere. ISSN 1994-0416. 14, s. 841–854. doi: 10.5194/tc-14-841-2020. Vis sammendrag

  The Northeast Greenland Ice Stream (NEGIS) currently drains more than 10 % of the Greenland Ice Sheet area and has recently undergone significant dynamic changes. It is therefore critical to accurately represent this feature when assessing the future contribution of Greenland to sea level rise. At present, NEGIS is reproduced in ice sheet models by inferring basal conditions using observed surface velocities. This approach helps estimate conditions at the base of the ice sheet but cannot be used to estimate the evolution of basal drag in time, so it is not a good representation of the evolution of the ice sheet in future climate warming scenarios. NEGIS is suggested to be initiated by a geothermal heat flux anomaly close to the ice divide, left behind by the movement of Greenland over the Icelandic plume. However, the heat flux underneath the ice sheet is largely unknown, except for a few direct measurements from deep ice core drill sites. Using the Ice Sheet System Model (ISSM), with ice dynamics coupled to a subglacial hydrology model, we investigate the possibility of initiating NEGIS by inserting heat flux anomalies with various locations and intensities. In our model experiment, a minimum heat flux value of 970 mW m−2 located close to the East Greenland Ice-core Project (EGRIP) is required locally to reproduce the observed NEGIS velocities, giving basal melt rates consistent with previous estimates. The value cannot be attributed to geothermal heat flux alone and we suggest hydrothermal circulation as a potential explanation for the high local heat flux. By including high heat flux and the effect of water on sliding, we successfully reproduce the main characteristics of NEGIS in an ice sheet model without using data assimilation.

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• Conrad, Clinton Phillips; Weerdesteijn, Maaike Francine Maria; Ramirez, Florence Dela Cruz & Selway, Kate (2024). Rapid Earth uplift where the Iceland Plume Track Crosses Greenland: GIA modelling and MT Constraints.
• Weerdesteijn, Maaike Francine Maria & Conrad, Clinton Phillips (2024). Rapid Earth uplift in southeast Greenland driven by recent ice melt above low-viscosity upper mantle.
• Heyn, Björn Holger; Shephard, Grace & Conrad, Clinton Phillips (2024). Prolonged multi-phase volcanism in the Arctic induced by plume-lithosphere interaction.
• Conrad, Clinton Phillips (2024). Geodynamic implications of lateral viscosity variations in the mantle.
• Ramirez, Florence Dela Cruz; Selway, Kate; Conrad, Clinton Phillips; Smirnov, Maxim & Maupin, Valerie (2023). Lateral and radial viscosity variations beneath Fennoscandia inferred from seismic and MT observations.
• Weerdesteijn, Maaike Francine Maria & Conrad, Clinton Phillips (2023). Rapid Earth uplift in southeast Greenland driven by recent ice melt above low-viscosity upper mantle.
• Ramirez, Florence Dela Cruz; Conrad, Clinton Phillips & Selway, Kate (2023). Plug flow and its associated grain-size variation in the oceanic asthenosphere explain the low seismic Q zone.
• Etzelmüller, Bernd; Lilleøren, Karianne Staalesen; Conrad, Clinton Phillips; Åkesson, Henning & Lund, Martin (2023). GeoOnsdag Spesial "Arven etter Esmark" - Sjå opptak frå foredraget. [Internett]. https://www.mn.uio.no/geo/om/organisasjon/geohyd/aktuelt/geo.
• Åkesson, Henning; Etzelmüller, Bernd; Lund, Erik Martin; Conrad, Clinton Phillips & Lilleøren, Karianne Staalesen (2023). Arven etter Esmark - GeoOnsdag Spesial. Vis sammendrag

  Arven etter Esmark, Bernd Etzelmüller/Karianne Lilleøren Imagining Esmark’s Lost Scandinavian Ice, Clint Conrad Gårsdagens is - fremtidens fasit, Henning Åkesson Wind of change, Martin Lund

• Heyn, Björn Holger; Conrad, Clinton Phillips & Shephard, Grace (2023). Plume-lithosphere interaction and continental plume tracks.
• Shephard, Grace; Heyn, Björn Holger & Conrad, Clinton Phillips (2023). Large-scale volcanism at the top of the world; plume and melt modelling of the High Arctic Large Igneous Province (HALIP).
• Heyn, Björn Holger; Shephard, Grace & Conrad, Clinton Phillips (2023). Locally amplified plume-lithosphere interaction and multiple melting events for 2-phase flow models.
• Shephard, Grace; Heyn, Björn Holger & Conrad, Clinton Phillips (2023). Prolonged multi-phase magmatism due to plume-lithosphere interaction as applied to the High Arctic Large Igneous Province.
• Heyn, Björn Holger; Shephard, Grace & Conrad, Clinton Phillips (2023). Amplification of sub-lithospheric dynamics by melt migration during plume-lithosphere interaction.
• Heyn, Björn Holger & Conrad, Clinton Phillips (2023). Development and implications of a free base for numerical models.
• Conrad, Clinton Phillips (2023). Imagining Esmark's Lost Scandinavian Ice.
• Conrad, Clinton Phillips (2023). Sea Level and the Solid Earth.
• Ebbing, J.; Fullea, J.; Root, B.; Conrad, Clinton Phillips & 3D Earth Study Team, The (2022). 3D Earth – Towards a digital twin for the geosphere.
• Ramirez, Florence Dela Cruz; Selway, Kate; Conrad, Clinton Phillips & Lithgow-Bertelloni, C. (2022). Constraining Upper Mantle Viscosity Using Temperature and Water Content Inferred from Seismic and Mag-netotelluric Data.
• Root, B.; Conrad, Clinton Phillips; Ebbing, J.; Fullea, J. & Lebedev, S. (2022). 4D Deep Dynamic Earth project: Recommendations for future research.
• Selway, Katherine (2022). Climate science on the Greenland Ice Sheet. [Internett]. https://www.youtube.com/watch?v=fLzWPcyAH7c.
• Heyn, Björn Holger & Shephard, Grace (2022). Revealing “invisible” plume tracks beneath continents.
• Wessel, Paul; Chase, Andrew; Frazer, L.N. & Conrad, Clinton Phillips (2022). A method for examining recent drifts of Pacific hotspots.
• Robert, Boris; Conrad, Clinton Phillips; Steinberger, Bernhard & Domeier, Mathew Michael (2022). Linking plate kinematics and true polar wander over the last 250 Myrs.
• Paul, Jyotirmoy; Conrad, Clinton Phillips; Becker, Thorsten W. & Ghosh, Attreyee (2022). Self-induced craton compression: Potential implications for craton stability.
• Conrad, Clinton Phillips (2022). The first magnetotelluric survey of the interior of Greenland. [Fagblad]. https://eu-polarnet.eu/newsletter-october-2022/.
• Heyn, Björn Holger (2022). Forskere har undersøkt to enorme, mystiske strukturer i jordens indre. [Avis]. https://www.forskning.no/geologi/forskere-har-undersokt-to-e.
• Conrad, Clinton Phillips (2022). Deep down temperature shifts give rise to eruptions. [Avis]. https://www.esa.int/Applications/Observing_the_Earth/FutureE.
• Rolf, Tobias; Crameri, Fabio; Heyn, Björn Holger & Thielmann, Marcel (2022). Testing a (quasi-)free base for modelling core-mantle boundary topography.
• Heyn, Björn Holger & Conrad, Clinton Phillips (2022). Basal erosion and surface heat flux anomalies associated with plume-lithosphere interaction beneath continents.
• Conrad, Clinton Phillips (2021). Sea level in a plastic cup. Vis sammendrag

  Eight ways to change the water level in a plastic cup – and global sea level

• Heyn, Björn Holger & Conrad, Clinton Phillips (2021). Plume-induced heat flux anomalies and the associated thinning of the continental lithosphere.
• Weerdesteijn, Maaike Francine Maria; Conrad, Clinton Phillips; Hollyday, A.; Austermann, J. & Gassmöller, R. (2021). Extending the open-source code ASPECT to solve the sea level equation on a heterogeneous Earth.
• Conrad, Clinton Phillips (2021). Sea Level and the Solid Earth. Vis sammendrag

  Sea level presents a fundamental boundary on our planet, for geological processes, biological species, and human society. It is therefore important to understand how this boundary changes with time. Since the ice ages, and even recently, major changes in sea level have been driven by changes to the volume of seawater (e.g., via exchange with continental ice). However, this mass transfer from land storage to the oceans also deforms both the land and sea surfaces, inducing large regional variations in sea level that affect projections of sea level change on coastlines. On longer geological timescales, spanning many millions of years, a variety of solid earth deformation processes drive most of the observed sea level change. These processes include ridge volume change, sediment accumulation, seafloor volcanism, dynamic topography, and continental orogeny, and they affect sea level by changing the volume of the ocean basins. One the longest timescales, changes to the volume of seawater are again the most important factor, but it is water exchange with Earth’s deep interior, rather than exchange the continental reservoirs, that controls the sea level. In this seminar I will discuss sea level changes occurring throughout Earth’s history, across timescales ranging from billions of years to decades, and the role that various different solid earth deformation processes play in determining the level of the sea.

• Weerdesteijn, Maaike Francine Maria; Conrad, Clinton Phillips; Reusen, J.M.; Steffen, R. & Naliboff, J. (2021). Solid earth uplift due to contemporary ice melting above low-viscosity regions of Greenland’s upper mantle.
• Conrad, Clinton Phillips (2021). Global Mantle Flow Patterns and the Time Dependence Dynamic Topography at Earth’s Surface and CMB.
• Conrad, Clinton Phillips (2021). Earth’s History of Changing Sea Level: Billions of Years to Decades .
• Conrad, Clinton Phillips (2021). Tectonic Reconstructions of Past Sea Level, Dynamic Topography and the Deep Water Cycle .
• Heyn, Björn Holger; Conrad, Clinton Phillips & Selway, Kate (2020). Numerical constraints on heat flux variations and lithospheric thinning associated with passage of the Iceland plume beneath Greenland.
• Weerdesteijn, Maaike Francine Maria; Conrad, Clinton Phillips; Selway, Kate; Naliboff, John & Gassmöller, Rene (2020). Developing a 3D glacial isostatic adjustment modeling code using ASPECT.
• Conrad, Clinton Phillips (2020). Korona­krisen vinge­klippet UiO-forskere. [Avis]. Universitas.
• Conrad, Clinton Phillips (2020). Sea Level and the Solid Earth, Interacting Across Timescales. Vis sammendrag

  Sea level presents a fundamental boundary on our planet, for geological processes, biological species, and human society. It is therefore important to understand how this boundary changes with time. Since the ice ages, and even recently, major changes in sea level have been driven by changes to the volume of seawater (e.g., via exchange with continental ice). However, this mass transfer from land storage to the oceans also deforms both the land and sea surfaces, inducing large regional variations in sea level that affect projections of sea level change on coastlines. On longer geological timescales, spanning many millions of years, a variety of solid earth deformation processes drive most of the observed sea level change. These processes include ridge volume change, sediment accumulation, seafloor volcanism, dynamic topography, and continental orogeny, and they affect sea level by changing the volume of the ocean basins. One the longest timescales, changes to the volume of seawater are again the most important factor, but it is water exchange with Earth’s deep interior, rather than exchange the continental reservoirs, that controls the sea level. In this seminar I will discuss sea level changes occurring throughout Earth’s history, across timescales ranging from billions of years to decades, and the role that various different solid earth deformation processes play in determining the level of the sea.

• Ramirez, Florence; Selway, Kate & Conrad, Clinton Phillips (2020). Integrating magnetotelluric and seismic geophysical observations to improve upper mantle viscosity estimates beneath polar regions.
• Conrad, Clinton Phillips; Selway, Kate; Weerdesteijn, Maaike Francine Maria; Smith-Johnsen, Silje; Nisancioglu, Kerim Hestnes & Karlsson, Nanna B (2020). Magnetotelluric Constraints on Upper Mantle Viscosity Structure and Basal Melt Beneath the Greenland Ice Sheet.
• Weerdesteijn, Maaike Francine Maria; Conrad, Clinton Phillips; Naliboff, John & Selway, Kate (2020). Developing an open-source 3D glacial isostatic adjustment modeling code using ASPECT.
• Weerdesteijn, Maaike Francine Maria; Conrad, Clinton Phillips; Gassmöller, Rene; Naliboff, John & Selway, Kate (2020). An Open-source 3D Glacial Isostatic Adjustment Modeling Code using ASPECT.
• Hartmann, Robert; Ebbing, Jörg & Conrad, Clinton Phillips (2020). RFBupdate_for_SELEN. Vis sammendrag

  Repository including a guide and all required files to update SELEN2.9.12/2.9.13 for consideration of rotational feedback (RFB) in the sea level equation (SLE). ################################################################################ SELEN is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or at your option) any later version. SELEN is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with SELEN. If not, see http://www.gnu.org/licenses/

• Weerdesteijn, Maaike Francine Maria; Conrad, Clinton Phillips; Selway, Kate & Ramirez, Florence (2020). Magnetotelluric Analysis for Greenland and Postglacial Isostatic Evolution (MAGPIE).
• Ramirez, Florence; Selway, Kate & Conrad, Clinton Phillips (2020). Using magnetotelluric and seismic geophysical observations to infer viscosity for Glacial Isostatic Adjustment calculations.
• Conrad, Clinton Phillips (2020). Earth's History of Changing Sea Level.
• Selway, Kate; Conrad, Clinton Phillips; Ramirez, Florence & Weerdesteijn, Maaike Francine Maria (2020). How can geophysical imaging help constrain mantle viscosity to improve glacial isostatic adjustment models?
• Conrad, Clinton Phillips; Selway, Kate; Weerdesteijn, Maaike Francine Maria; Smith-Johnsen, Silje; Nisancioglu, Kerim Hestnes & Karlsson, Nanna B (2020). Magnetotelluric Constraints on Upper Mantle Viscosity Structure and Basal Melt Beneath the Greenland Ice Sheet.
• Hartmann, Robert; Ebbing, Jörg & Conrad, Clinton Phillips (2020). A Multiple 1D Earth Approach (M1DEA) to account for lateral viscosity variations in solutions of the sea level equation: An application for glacial isostatic adjustment by Antarctic deglaciation.
• Conrad, Clinton Phillips (2020). Slowdown in plate tectonics may have led to Earth’s ice sheets. [Tidsskrift]. Science.
• Conrad, Clinton Phillips (2020). Dedikert til forskning på geodynamikk – Clint Conrad er tildelt Evgueni Burov medaljen for 2020 . [Internett]. Geofag nyheter.
• Conrad, Clinton Phillips (2020). Pris til UiO-professor . [Internett]. geoforskning.no.
• Weerdesteijn, Maaike Francine Maria; Conrad, Clinton Phillips & Selway, Kate (2020). Developing an open-source 3D glacial isostatic adjustment modeling code using ASPECT.
• Ramirez, Florence; Selway, Kate & Conrad, Clinton Phillips (2020). Relationship between magnetotelluric and seismic geophysical observations and mantle viscosity.
• Selway, Kate; Conrad, Clinton Phillips; Ramirez, Florence; Karlsson, Nanna B; Weerdesteijn, Maaike Francine Maria & Heyn, Björn Holger (2020). How magnetotellurics can aid cryosphere studies: mantle rheology, GIA, surface heat flow, and basal melting.
• Gaina, Carmen; Barletta, V.; Conrad, Clinton Phillips; Ebbing, Jörg; Forsberg, R. & Ferraccioli, Fausto [Vis alle 9 forfattere av denne artikkelen] (2020). Interplay of cryosphere, solid earth and dynamic mantle in the Arctic.
• Conrad, Clinton Phillips (2020). Forsker på geodynamikk – Clint Conrad har fått Evgueni Burov Medal. [Internett]. Titan.
• Weerdesteijn, Maaike Francine Maria; Conrad, Clinton Phillips; Selway, Kate & Ramirez, Florence (2019). Magnetotelluric Analysis for Greenland and Postglacial Isostatic Evolution (MAGPIE).
• Weerdesteijn, Maaike Francine Maria; Conrad, Clinton Phillips; Selway, Kate & Ramirez, Florence (2019). Magnetotelluric Analysis for Greenland and Postglacial Isostatic Evolution (MAGPIE).
• Weerdesteijn, Maaike Francine Maria; Conrad, Clinton Phillips; Selway, Kate & Ramirez, Florence (2019). Magnetotelluric Analysis for Greenland and Postglacial Isostatic Evolution (MAGPIE).
• Conrad, Clinton Phillips; Selway, Kate; Weerdesteijn, Maaike Francine Maria; Smith-Johnsen, Silje; Nisancioglu, Kerim Hestnes & Karlsson, Nanna B (2019). Magnetotelluric Constraints on Upper Mantle Viscosity Structure and Basal Melt Beneath the Greenland Ice Sheet.
• Conrad, Clinton Phillips (2019). Sea level and the Solid Earth.
• Conrad, Clinton Phillips; Selway, Kate; Weerdesteijn, Maaike; Smith-Johnsen, Silje; Nisancioglu, Kerim Hestnes & Karlsson, Nanna B (2019). Magnetotelluric constraints on upper mantle viscosity structure and basal melt beneath the Greenland ice sheet.
• Weerdesteijn, Maaike; Selway, Kate & Conrad, Clinton Phillips (2019). Magnetotelluric Analysis for Greenland and Postglacial Isostatic Evolution (MAGPIE).
• Conrad, Clinton Phillips (2019). Arctic Deglaciation and its Connection to the Deep Earth.
• Conrad, Clinton Phillips; Selway, Kate; Weerdesteijn, Maaike & Smith-Johnsen, Silje (2019). Magnetotelluric Analysis for Greenland and Postglacial Isostatic Evolution (MAGPIE).
• Weerdesteijn, Maaike; Conrad, Clinton Phillips; Selway, Kate & Ramirez, Florence (2019). MAGPIE: Magnetotelluric Analysis for Greenland and Postglacial Isostatic Evolution.
• Selway, Kate; Conrad, Clinton Phillips; Nisancioglu, Kerim Hestnes; Karlsson, Nanna B & Steinberger, Bernhard (2019). The MAGPIE Project: Magnetotelluric Analysis of Greenland and Postglacial Isostatic Evolution .
• Nisancioglu, Kerim Hestnes (2019). Greenland and Nordic Seas/Arctic Variability.
• Hopper, John R.; Fatah, Rader Abdul; Gaina, Carmen; Geissler, Wolfram H; Funck, Thomas & Kimbell, Geoffrey S [Vis alle 7 forfattere av denne artikkelen] (2019). Sediment thickness, crustal thickness, and residual topography of the North Atlantic: estimating dynamic topography around Iceland.
• Conrad, Clinton Phillips (2019). The MAGPIE Blog. [Internett]. https://magpiegreenland.wordpress.com/. Vis sammendrag

  We started the MAGPIE project in April 2019 with funding from Forskningsrådet, which is the Research Council of Norway. Our ultimate goal is to develop better estimates for current and recent melting of the Greenland Ice Sheet. Achieving this will require us to coordinate an international collaboration between many different individuals, each contributing a their own unique expertise. As we work towards our goal, we will learn a great deal about the glacial history of the Greenland Ice Sheet, as well as the deformation patterns of the rocky mantle beneath the ice. We will learn how the Earth beneath Greenland has uplifted as ice has melted during the ice ages, and how it continues to uplift today as a result of current melting.

• Weerdesteijn, Maaike Francine Maria & Conrad, Clinton Phillips (2023). Solid earth deformation due to glacial mass changes above low-viscosity upper mantle: Model development, importance of contemporary ice melt, and an application to southeast Greenland. Universitetet i Oslo. ISSN 1501-7710. Vis sammendrag

  Changes to Earth’s climate redistribute masses of ice and water on Earth's surface. These loads cause the solid earth to deform, and it is commonly thought that this happens in two ways: ice age ice melting caused a long-term viscous flow that is still occurring, and modern ice melting drives an instantaneous elastic deformation. However, regions in West Antarctica and southeast Greenland are currently uplifting so rapidly that another deformation mechanism must be important. Here we study how confined regions of unusually weak rocks within Earth’s upper mantle can deform viscously, generating rapid surface uplift. This doctoral thesis presents a new viscoelastic earth deformation model that can accommodate large lateral variations in Earth structure. We benchmark this code and use it to investigate the poorly understood role of small (~100s km) regions of unusually low-viscosity mantle beneath rapidly melting ice. We then apply our code to southeast Greenland, a region likely weakened by the Iceland plume ~40 Ma ago. We show that the uplift here is dominated by a viscous response to recent and rapid deglaciation, occurring within the past few decades. This viscous contribution is not usually considered, but will become increasingly important in the future as deglaciation accelerates.

• Ramirez, Florence Dela Cruz & Conrad, Clinton Phillips (2022). Improving upper mantle viscosity estimates: Constraints from seismic and magnetotelluric data, and impacts on asthenospheric flow. Universitetet i Oslo. ISSN 1501-7710. Vis sammendrag

  A simplified Earth’s structure consists of three geological layers: a stiff lithosphere (plates), a mantle and a core. Like for an example your favorite yogurt, the rock in the solid mantle can be flowing, but it requires an enormous amount of force to deform it and a time scale over thousands to millions of years! To quantify how fast the deformation process would be for a certain applied force, the physical quantity “viscosity” is used. For instance, water has lower viscosity than yogurt, which enables you to stir the water faster than the yogurt. For the mantle, viscosity affects how fast the plates can move laterally and vertically. An example for this is Scandinavia (including Norway), which is continuously uplifting as a response to melting of past ice sheet from “siste istid” with up to 3000 meters ice caps, thereby influencing climate and sea level. Unfortunately, mantle viscosity cannot be measured directly, but is commonly estimated from surface deformations. This doctoral study introduces a method for estimating viscosity using geophysical observations (seismic and magnetotelluric), which reflect realistic mantle conditions such as temperature, water content, and partial melt that control viscosity. The method provides useful results for Scandinavia and can be applied in other places as well. Resulting viscosity models can aid in geodynamic studies such as modelling flow patterns below the moving oceanic plates.

• Wang, Helene; Magni, Valentina & Conrad, Clinton Phillips (2022). Hydrous regions of the mantle transition zone affect patterns of intraplate volcanism. Universitetet i Oslo.

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