Clinton Phillips Conrad

• 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 Full text in Research Archive. Show summary

  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.

• Heyn, Björn Holger; Conrad, Clinton Phillips & Trønnes, Reidar G (2020). Core-mantle boundary topography and its relation to the viscosity structure of the lowermost mantle. Earth and Planetary Science Letters.  ISSN 0012-821X.  543 . doi: 10.1016/j.epsl.2020.116358 Full text in Research Archive. Show summary

  Two large areas of anomalously low seismic velocities are visible in all tomographic models of the lowermost mantle. Depending on the density structure of these Large Low Shear Velocity Provinces (LLSVPs), the core-mantle boundary (CMB) will deform upwards or downwards due to isostatic and dynamic topography, the latter being sensitive to the viscosity structure of the lowermost mantle. Heterogeneities in the viscosity structure, although difficult to constrain, might be especially important if the LLSVPs are thermochemical piles with elevated intrinsic viscosity as suggested by mineral physics. Based on numerical models, we identify a short-wavelength (about 80-120 km wide, up to a few km deep) topographic depression that forms around the pile edges if the pile is more viscous than the surrounding mantle. The depression forms when a wedge of thermal boundary layer material becomes compressed against the viscous pile, and is enhanced by relative uplift of the CMB beneath the pile by plumes rising above it. The depth and asymmetry of the depression constrain the magnitude of the viscosity contrast between pile and the surrounding mantle. Furthermore, (periodic) plume initiation and pile collapse at the pile margin systematically modify the characteristic depression, with a maximum in asymmetry and depth at the time of plume initiation. Core-reflected waves or scattered energy may be used to detect this topographic signature of stiff thermochemical piles at the base of the mantle.

• Heyn, Björn Holger; Conrad, Clinton Phillips & Trønnes, Reidar G (2020). How Thermochemical Piles Can (Periodically) Generate Plumes at Their Edges. Journal of Geophysical Research (JGR): Solid Earth.  ISSN 2169-9313.  125(6) . doi: 10.1029/2019JB018726 Full text in Research Archive. Show summary

  Deep-rooted mantle plumes are thought to originate from the margins of the Large Low Shear Velocity Provinces (LLSVPs) at the base of the mantle. Visible in seismic tomography, the LLSVPs are usually interpreted to be intrinsically dense thermochemical piles in numerical models. Although piles deflect lateral mantle flow upward at their edges, the mechanism for localized plume formation is still not well understood. In this study, we develop numerical models that show plumes rising from the margin of a dense thermochemical pile, temporarily increasing its local thickness until material at the pile top cools and the pile starts to collapse back toward the core-mantle boundary (CMB). This causes dense pile material to spread laterally along the CMB, locally thickening the lower thermal boundary layer on the CMB next to the pile, and initiating a new plume. The resulting plume cycle is reflected in both the thickness and lateral motion of the local pile margin within a few hundred km of the pile edge, while the overall thickness of the pile is not affected. The period of plume generation is mainly controlled by the rate at which slab material is transported to the CMB, and thus depends on the plate velocity and the sinking rate of slabs in the lower mantle. A pile collapse, with plumes forming along the edges of the pile's radially extending corner, may, for example, explain the observed clustering of Large Igneous Provinces (LIPs) in the southeastern corner of the African LLSVP around 95–155 Ma.

• Karlsen, Krister Stræte; Domeier, Mathew; Gaina, Carmen & Conrad, Clinton Phillips (2020). A tracer-based algorithm for automatic generation of seafloor age grids from plate tectonic reconstructions. Computers & Geosciences.  ISSN 0098-3004.  140 . doi: 10.1016/j.cageo.2020.104508 Full text in Research Archive. Show summary

  The age of the ocean floor and its time-dependent age distribution control fundamental features of the Earth, such as bathymetry, sea level and mantle heat loss. Recently, the development of increasingly sophisticated reconstructions of past plate motions has provided models for plate kinematics and plate boundary evolution back in geological time. These models implicitly include the information necessary to determine the age of ocean floor that has since been lost to subduction. However, due to the lack of an automated and efficient method for generating global seafloor age grids, many tectonic models, most notably those extending back into the Paleozoic, are published without an accompanying set of age models for oceanic lithosphere. Here we present an automatic, tracer-based algorithm that generates seafloor age grids from global plate tectonic reconstructions with defined plate boundaries. Our method enables us to produce novel seafloor age models for the Paleozoic’s lost ocean basins. Estimated changes in sea level based on bathymetry inferred from our new age grids show good agreement with sea level record estimations from proxies, providing a possible explanation for the peak in sea level during the assembly phase of Pangea. This demonstrates how our seafloor age models can be directly compared with observables from the geologic record that extend further back in time than the constraints from preserved seafloor. Thus, our new algorithm may also aid the further development of plate tectonic reconstructions by strengthening the links between geological observations and tectonic reconstructions of deeper time.

• Kiraly, Agnes; Conrad, Clinton Phillips & Hansen, Lars N. (2020). Evolving Viscous Anisotropy in the Upper Mantle and Its Geodynamic Implications. Geochemistry Geophysics Geosystems.  ISSN 1525-2027.  21(10) . doi: 10.1029/2020GC009159 Full text in Research Archive. Show summary

  Asthenospheric shear causes some minerals, particularly olivine, to develop anisotropic textures that can be detected seismically. In laboratory experiments, these textures are also associated with anisotropic viscous behavior, which should be important for geodynamic processes. To examine the role of anisotropic viscosity for asthenospheric deformation, we developed a numerical model of coupled anisotropic texture development and anisotropic viscosity, both calibrated with laboratory measurements of olivine aggregates. This model characterizes the time‐dependent coupling between large‐scale formation of lattice‐preferred orientation (i.e., texture) and changes in asthenospheric viscosity for a series of simple deformation paths that represent upper mantle geodynamic processes. We find that texture development beneath a moving surface plate tends to align the a axes of olivine into the plate motion direction, which weakens the effective viscosity in this direction and increases plate velocity for a given driving force. Our models indicate that the effective viscosity increases for shear in the horizontal direction perpendicular to the a axes. This increase should slow plate motions and new texture development in this perpendicular direction and could impede changes to the plate motion direction for tens of millions of years. However, the same well‐developed asthenospheric texture may foster subduction initiation perpendicular to the plate motion and deformations related to transform faults, as shearing on vertical planes seems to be favored across a sublithospheric olivine texture. These end‐member cases examining shear deformation in the presence of a well‐formed asthenospheric texture illustrate the importance of the mean olivine orientation, and its associated viscous anisotropy, for a variety of geodynamic processes.

• 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 Full text in Research Archive. Show summary

  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.

• Crameri, Fabio; Shephard, Grace & Conrad, Clinton Phillips (2019). Plate tectonics, In  Encyclopedia of Ecology. Reference Module in Earth Systems and Environmental Sciences.  Elsevier.  ISBN 978-0-12-409548-9.  Plate tectonics. Full text in Research Archive.
• Karlsen, Krister Stræte; Conrad, Clinton Phillips & Magni, Valentina (2019). Deep water cycling and sea level change since the breakup of Pangea. Geochemistry Geophysics Geosystems.  ISSN 1525-2027.  20(6), s 2919- 2935 . doi: 10.1029/2019GC008232 Full text in Research Archive. Show summary

  First‐order variations in sea level exhibit amplitudes of ∼200 m over periods that coincide with those of supercontinental cycles (∼300–500 Myr). Proposed mechanisms for this sea level change include processes that change the container volume of the ocean basins and the relative elevation of continents. Here we investigate how unbalanced rates of water exchange between Earth's surface and mantle interior, resulting from fluctuations in tectonic rates, can cause sea level changes. Previous modeling studies of subduction water fluxes suggest that the amount of water that reaches sub‐arc depths is well correlated with the velocity and age of the subducting plate. We use these models to calibrate a parameterization of the deep subduction water flux, which we together with a parameterization of mid‐ocean ridge outgassing, then apply to reconstructions of Earth's tectonic history. This allows us to estimate the global water fluxes between the oceans and mantle for the past 230 Myr and compute the associated sea level change. Our model suggests that a sea level drop of up to 130 m is possible over this period and that it was partly caused by the ∼150Ma rift pulse that opened the Atlantic and forced rapid subduction of old oceanic lithosphere. This indicates that deep water cycling may be one of the more important sea level changing mechanisms on supercontinental time scales and provides a more complete picture of the dynamic interplay between tectonics and sea level change.

• Paul, Jyotirmoy; Ghosh, Attreyee & Conrad, Clinton Phillips (2019). Traction and strain-rate at the base of the lithosphere: An insight into cratonic survival. Geophysical Journal International.  ISSN 0956-540X.  217(2), s 1024- 1033 . doi: 10.1093/gji/ggz079 Full text in Research Archive. Show summary

  Cratons are the oldest parts of the lithosphere, some of them surviving since Archean. Their long-term survival has sometimes been attributed to high viscosity and low density. In our study, we use a numerical model to examine how shear tractions exerted by mantle convection work to deform cratons by convective shearing. We find that although tractions at the base of the lithosphere increase with increasing lithosphere thickness, the associated strain rates decrease. This inverse relationship between stress and strain-rate results from lateral viscosity variations along with the model’s free slip condition imposed at the Earth’s surface, which enables strain to accumulate along weak zones at plate boundaries. Additionally, we show that resistance to lithosphere deformation by means of convective shearing, which we express as an apparent viscosity, scales with the square of lithosphere thickness. This suggests that the enhanced thickness of the cratons protects them from convective shear, and allows them to survive as the least deformed areas of the lithosphere. Indeed, we show that the combination of a smaller asthenospheric viscosity drop and a larger cratonic viscosity, together with the excess thickness of cratons compared to the surrounding lithosphere, can explain their survival since Archean time.

• Steinberger, Bernhard; Conrad, Clinton Phillips; Osei Tutu, Anthony & Hoggard, Mark J. (2019). On the amplitude of dynamic topography at spherical harmonic degree two. Tectonophysics.  ISSN 0040-1951.  760, s 221- 228 . doi: 10.1016/j.tecto.2017.11.032 Show summary

  Two large, seismically slow regions in the lower mantle beneath Africa and the Pacific Ocean are sometimes referred to as “superplumes”. This name evokes images of large-scale active upwellings. However, it remains unclear whether these features are real or represent collections of multiple regular mantle plumes. Here, we investigate the implications of these upwellings for dynamic topography. We combine detailed measurements of oceanic residual topography from Hoggard et al. (2016) with continental constraints derived from CRUST1.0 to produce a global model expanded in spherical harmonics. Observed dynamic topography is subsequently compared to predictions derived from mantle flow following Steinberger (2016) using tomographic density models. Results yield relatively good overall agreement and amplitude spectra with similar slopes, except for degree two (i.e. > 10,000 km wavelengths) where predicted amplitude is more than two times as large and is dominated by contributions from the lower mantle. Predictive models suggest two large-scale uplifted regions above the “superplumes” that are barely seen in the observed topography. We suggest that this mismatch can only partly be reconciled by altering the seismic velocity to density conversion factor or by including the effects of lower mantle chemical heterogeneity. In addition, it may be important to consider more significant revisions to the lower mantle flow patterns, such as those possibly induced by different radial viscosity profiles and laterally-varying or anisotropic lower mantle viscosity.

• Torsvik, Trond Helge; Steinberger, Bernhard; Shephard, Grace; Doubrovine, Pavel; Gaina, Carmen; Domeier, Mathew; Conrad, Clinton Phillips & Sager, William (2019). Pacific‐Panthalassic reconstructions: Overview, errata and the way forward. Geochemistry Geophysics Geosystems.  ISSN 1525-2027.  20(7), s 3659- 3689 . doi: 10.1029/2019GC008402 Full text in Research Archive.
• Wessel, Paul & Conrad, Clinton Phillips (2019). Assessing Models for Pacific Absolute Plate and Plume Motions. Geochemistry Geophysics Geosystems.  ISSN 1525-2027.  20(12), s 6016- 6032 . doi: 10.1029/2019GC008647 Full text in Research Archive. Show summary

  Absolute plate motion (APM) models derived from hot spot trails must satisfy trail geometries, ages, and paleolatitudes, which requires modeling explicit plume motions. Models lacking plume motions or derived independently from seamounts must also fit these data, provided the implicit plume motions are geodynamically reasonable. We evaluate eight Pacific APM models; three have explicitly modeled plume motions. Seven derive from seamount age progressions; one is a geodynamic model driven by slab pull and ridge push. Using the long‐lived Hawaii‐Emperor and Louisville chains, we derive implicit motions of Hawaii and Louisville plumes for models lacking explicit estimates and compare them with observed paleolatitudes. Inferred plume motions are plausible given rheological constraints on mantle flow, but rates vary considerably and not all models fit the data well. One potential endmember model predicts no APM direction change at 50 Ma, which best explains trails and paleolatitudes, minimizes predicted rotation of Pacific‐Farallon ridge and assumes no true polar motion, yet its implicit plume drift is inconsistent with global circulation models. Alternatively, a global moving hot spot model yields acceptable fits to geometry and ages, implies a major APM change at 50 Ma, but requires significant true polar wander to explain observed paleolatitudes. The inherent inconsistency between age progressions and paleolatitudes may be reconciled by true polar wander, yet questions remain about the accuracy of age progressions for older sections of the Emperor and Louisville chains, the independent geologic evidence for an APM change at 50 Ma, and the uniqueness and relevance of true polar wander estimates.

• Crameri, Fabio; Conrad, Clinton Phillips; Montési, Laurent & Lithgow-Bertelloni, Carolina (2018). The dynamic life of an oceanic plate. Tectonophysics.  ISSN 0040-1951.  760, s 107- 135 . doi: 10.1016/j.tecto.2018.03.016 Full text in Research Archive. Show summary

  As the Earth's primary mode of planetary cooling, the oceanic plate is created at mid-ocean ridges, transported across the planet's surface, and destroyed at subduction zones. The evolution of its buoyancy and rheology during its lifespan maintains the coherence of the plate as a distinct geological entity and controls the localised deformation and vertical material exchange at plate boundaries, which enables the horizontal ocean-plate movements. These motions intimately link the oceanic plate to the overarching overturn of Earth's mantle: The plate forms out of rising mantle material at spreading ridges; it cools the Earth's interior as the cold thermal boundary layer to mantle convection; and its sinking portions drive not only the plate itself but also dominate global flow in the mantle. We scrutinise here the entire life cycle of the oceanic plate, starting with its birth at the mid-ocean ridge, including the thermal, rheological, and chemical conditions of initiation, followed by plate maturation as it ages and cools while crossing the seafloor, and finishing with the dynamics of plate destruction as it retires at the subduction zone to become a deeper part of Earth's convective system. We find that the full range of dynamic behaviour of the oceanic plate, including its forcing and overall framework within Earth's convecting system, is not fully captured by the existing concept of Plate Tectonics, which describes solely the horizontal surface kinematics of all plates. Therefore, we introduce a more specific and at the same time more integral concept named “Ocean-Plate Tectonics” that more specifically describes the dynamic life of the oceanic plate and accounts for the knowledge gained during the past 50 years. This “Ocean-Plate Tectonics” must have emerged on Earth at least 1 Billion years ago, and dominates Earth's dynamics today.

• Heyn, Björn Holger; Conrad, Clinton Phillips & Trønnes, Reidar G (2018). Stabilizing effect of compositional viscosity contrasts on thermochemical piles. Geophysical Research Letters.  ISSN 0094-8276.  45(15), s 7523- 7532 . doi: 10.1029/2018GL078799 Full text in Research Archive. Show summary

  The large low shear velocity provinces (LLSVPs) observed in the lowermost mantle are widely accepted as chemically distinct thermochemical 'piles', but their origin and long-term evolution remain poorly understood. The survival time and shape of the LLSVPs are thought to be mainly controlled by their compositional density, while their viscosity has beeen considered less important. Based on recent constraints on chemical reactions between mantle and core, a more complex viscosity structure of the lowermost mantle, possibly including high viscosity thermochemical pile material, seems reasonable. In this study, we use numerical models to identify a trade-off between compositional viscosity and density contrasts required for long-term stability of thermochemical piles, which permits lower-density and higher-viscosity piles. Moreover, our results indicate more restrictive stability conditions during periods of strong deformation-induced entrainment, e.g. during initial pile formation, which suggests long-term pile survival.

• Watkins, C. Evan & Conrad, Clinton Phillips (2018). Constraints on dynamic topography from asymmetric subsidence of the mid-ocean ridges. Earth and Planetary Science Letters.  ISSN 0012-821X.  484, s 264- 275 . doi: 10.1016/j.epsl.2017.12.028 Show summary

  Stresses from mantle convection deflect Earth's surface vertically, producing dynamic topography that is important for continental dynamics and sea-level change but difficult to observe due to overprinting by isostatic topography. For long wavelengths (∼104 km), the amplitude of dynamic topography is particularly uncertain, with mantle flow models typically suggesting larger amplitudes (>1000 m) than direct observations. Here we develop a new constraint on the amplitude of long-wavelength dynamic topography by examining asymmetries in seafloor bathymetry across mid-ocean ridges. We compare bathymetric profiles across the Mid-Atlantic Ridge (MAR) and the East Pacific Rise (EPR) and we find that the South American flank of both ridges subsides faster than its opposing flank. This pattern is consistent with dynamic subsidence across South America, supported by downwelling in the lower mantle. To constrain the amplitude of dynamic topography, we compare bathymetric profiles across both ridges after correcting bathymetry for several different models of dynamic topography with varying amplitudes and spatial patterns. We find that long-wavelength dynamic topography with an amplitude of only ∼500 m explains the observed asymmetry of the MAR. A similar model can explain EPR asymmetry but is complicated by additional asymmetrical topography associated with tectonic, crustal thickness, and/or asthenospheric temperature asymmetries across the EPR. After removing 500 m of dynamic topography, both the MAR and EPR exhibit a slower seafloor subsidence rate (∼280–290 m/Myr1/2) than previously reported. Our finding of only ∼500 m of long-wavelength dynamic topography may indicate the importance of thermochemical convection and/or large viscosity variations for lower mantle dynamics.

View all works in Cristin

• Conrad, Clinton Phillips (2020, 26. mai). Pris til UiO-professor. [Internett].  geoforskning.no.
• Conrad, Clinton Phillips (ed.) (2020). Clint Conrad's Website.
• Conrad, Clinton Phillips (2020, 15. mai). Dedikert til forskning på geodynamikk – Clint Conrad er tildelt Evgueni Burov medaljen for 2020. [Internett].  Geofag nyheter.
• Conrad, Clinton Phillips (2020). Earth's History of Changing Sea Level.
• Conrad, Clinton Phillips (2020, 18. mai). Forsker på geodynamikk – Clint Conrad har fått Evgueni Burov Medal. [Internett].  Titan.
• Conrad, Clinton Phillips (2020, 01. september). Korona­krisen vinge­klippet UiO-forskere.  Universitas.
• Conrad, Clinton Phillips (2020). Sea Level and the Solid Earth, Interacting Across Timescales. Show summary

  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.

• Conrad, Clinton Phillips (2020, 22. desember). Slowdown in plate tectonics may have led to Earth’s ice sheets. [Tidsskrift].  Science.
• Conrad, Clinton Phillips; Domeier, Mathew; Selway, Kate & Heyn, Björn Holger (2020). A link between seamount volcanism and thermochemical piles in the deepest mantle.
• 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.
• 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.
• Gaina, Carmen; Barletta, V.; Conrad, Clinton Phillips; Ebbing, Jörg; Forsberg, R.; Ferraccioli, Fausto; Heincke, B.; Lebedev, Sergei & van der Wal, Wouter (2020). Interplay of cryosphere, solid earth and dynamic mantle in the Arctic.
• 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.
• Hartmann, Robert; Ebbing, Jörg & Conrad, Clinton Phillips (2020). RFBupdate_for_SELEN. Show summary

  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/

• 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.
• Heyn, Björn Holger; Conrad, Clinton Phillips & Trønnes, Reidar G (2020). How thermochemical piles initiate plumes at their edges.
• Heyn, Björn Holger; Conrad, Clinton Phillips & Trønnes, Reidar G (2020). How thermochemical piles initiate plumes at their edges.
• Heyn, Björn Holger; Conrad, Clinton Phillips & Trønnes, Reidar G (2020). How thermochemical piles initiate plumes at their edges. European Geosci. Union, Gen. Assembly, Geophys. Res. Abstr. EGU2020-5577.. European Geosci. Union, Gen. Assembly, Geophys. Res. Abstr..
• Karlsen, Krister Stræte; Conrad, Clinton Phillips & Magni, Valentina (2020). Deep water cycling and sea level change since the breakup of Pangea.
• Karlsen, Krister Stræte; Domeier, Mathew; Gaina, Carmen & Conrad, Clinton Phillips (2020). Tracer Tectonics. Show summary

  Tracer Tectonics (TracTec) is a Python toolbox for generating seafloor age grids from global plate tectonic reconstructions based on an algorithm developed by Krister S. Karlsen, in collaboration with Mathew Domeier, Carmen Gaina and Clinton P. Conrad, at the Centre for Earth Evolution and Dynamics, University of Oslo, Norway.

• Kiraly, Agnes; Conrad, Clinton Phillips & Hansen, Lars (2020). Evolving viscous anisotropy in the upper mantle and its geodynamic implications.
• Kiraly, Agnes; Conrad, Clinton Phillips & Hansen, Lars N. (2020). Evolving viscous anisotropy in the upper mantle and its geodynamic implications – Supplementary Materials, Data, and Code [Data set]. Show summary

  This dataset is related to the paper Evolving viscous anisotropy in the upper mantle and its geodynamic implications by Kiraly et al., which is in submission to Geochemistry Geophysics Geosystems (G-cube). Information about the data package can be found in the supplementary material attached to the article.

• Kiraly, Agnes; Conrad, Clinton Phillips; Hansen, Lars & Fraters, Menno RT (2020). The formation of viscous anisotropy in the asthenosphere and its effect on plate tectonics.
• Ramirez, Florence; Selway, Kate & Conrad, Clinton Phillips (2020). Integrating magnetotelluric and seismic geophysical observations to improve upper mantle viscosity estimates beneath polar regions.
• Ramirez, Florence; Selway, Kate & Conrad, Clinton Phillips (2020). Relationship between magnetotelluric and seismic geophysical observations and mantle viscosity.
• Ramirez, Florence; Selway, Kate & Conrad, Clinton Phillips (2020). Using magnetotelluric and seismic geophysical observations to infer viscosity for Glacial Isostatic Adjustment calculations.
• 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.
• 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?.
• 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.
• 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 & Selway, Kate (2020). Developing an open-source 3D glacial isostatic adjustment modeling code using ASPECT.
• Weerdesteijn, Maaike Francine Maria; Conrad, Clinton Phillips; Selway, Kate; Naliboff, John & Gassmöller, Rene (2020). Developing a 3D glacial isostatic adjustment modeling code using ASPECT.
• Weerdesteijn, Maaike Francine Maria; Conrad, Clinton Phillips; Selway, Kate & Ramirez, Florence (2020). 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 (2019). Patterns of mantle convection and plate tectonics.
• Conrad, Clinton Phillips (2019). Sea level and the Solid Earth.
• Conrad, Clinton Phillips (2019, 18. mai). The MAGPIE Blog. [Internett].  https://magpiegreenland.wordpress.com/. Show summary

  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.

• Conrad, Clinton Phillips; Domeier, Mathew; Selway, Kate & Heyn, Björn Holger (2019). A link between seamount volcanism and thermochemical piles in the deepest mantle.
• 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; Selway, Kate; Weerdesteijn, Maaike & Smith-Johnsen, Silje (2019). Magnetotelluric Analysis for Greenland and Postglacial Isostatic Evolution (MAGPIE).
• 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.
• Domeier, Mathew; Torsvik, Trond Helge; Conrad, Clinton Phillips; Steinberger, Bernhard; Doubrovine, Pavel V.; Trønnes, Reidar G; Werner, Stephanie C.; Shephard, Grace & Robert, Boris (2019). On the stability of Earth’s degree 2 mantle structure. European Geosci. Union, Gen. Assembly, Geophys. Res. Abstr..
• Domeier, Mathew; Torsvik, Trond Helge; Conrad, Clinton Phillips; Steinberger, Bernhard; Doubrovine, Pavel; Trønnes, Reidar G; Werner, Stephanie C.; Shephard, Grace & Robert, Boris (2019). On the stability of Earth’s degree 2 mantle structures.
• Gaina, Carmen; Mac Niocaill, Conall; Conrad, Clinton Phillips; Steinberger, Bernhard & Svensen, Henrik (2019). Linking plate tectonics and volcanism to deep earth dynamics - A tribute to Trond H. Torsvik. Tectonophysics.  ISSN 0040-1951.  760, s 1- 3 . doi: 10.1016/j.tecto.2019.03.002
• Heyn, Björn Holger; Conrad, Clinton Phillips & Trønnes, Reidar G (2019). Core-mantle boundary topography and its relation to lowermost mantle viscosity structure.
• Heyn, Björn Holger; Conrad, Clinton Phillips & Trønnes, Reidar G (2019). Heyn B, Conrad C, Trønnes R, 2019: Core-mantle boundary topography and its relation to lowermost mantle viscosity structure. Ada Lovelace Workshop on Modelling Mantle and Lithosphere Dynamics, Abstr. 71.. Ada Lovelace Workshop on Modelling Mantle and Lithosphere Dynamics. Abstr..
• Heyn, Björn Holger; Conrad, Clinton Phillips & Trønnes, Reidar G (2019). Heyn B, Conrad C, Trønnes R, 2019: Periodic plume generation at the edges of thermochemical piles. Ada Lovelace Workshop on Modelling Mantle and Lithosphere Dynamics. Abstr. 72.. European Geosci. Union, Gen. Assembly, Geophys. Res. Abstr..
• Heyn, Björn Holger; Conrad, Clinton Phillips & Trønnes, Reidar G (2019). Heyn B, Conrad C, Trønnes R, 2019: What core-mantle boundary topography can tell us about plume locations and the viscosity and density structure of thermochemical piles. European Geosci. Union, Gen. Assembly, Geophys. Res. Abstr. EGU2019-9714.. European Geosci. Union, Gen. Assembly, Geophys. Res. Abstr..
• Heyn, Björn Holger; Conrad, Clinton Phillips & Trønnes, Reidar G (2019). Linking surface volcanism and deep Earth: Piles, plumes, and dynamic topography.
• Heyn, Björn Holger; Conrad, Clinton Phillips & Trønnes, Reidar G (2019). Periodic plume generation at the edges of thermochemical piles.
• Heyn, Björn Holger; Conrad, Clinton Phillips & Trønnes, Reidar G (2019). What core-mantle boundary topography can tell us about plume locations and the viscosity and density structure of thermochemical piles.
• Hopper, John R.; Fatah, Rader Abdul; Gaina, Carmen; Geissler, Wolfram H; Funck, Thomas; Kimbell, Geoffrey S & Conrad, Clinton Phillips (2019). Sediment thickness, crustal thickness, and residual topography of the North Atlantic: estimating dynamic topography around Iceland.
• Karlsen, Krister Stræte; Conrad, Clinton Phillips & Magni, Valentina (2019). Deep water cycling and sea level change since the breakup of Pangea.
• Karlsen, Krister Stræte; Conrad, Clinton Phillips & Magni, Valentina (2019). Deep water cycling and sea level change since the breakup of Pangea.
• Kiraly, Agnes; Conrad, Clinton Phillips; Domeier, Mathew & Hansen, Lars (2019). Does anisotropic mantle viscosity impede changes in plate motion?.
• Kiraly, Agnes; Conrad, Clinton Phillips; Domeier, Mathew & Hansen, Lars (2019). Does anisotropic mantle viscosity impede changes in plate motions.
• Kiraly, Agnes; Conrad, Clinton Phillips & Hansen, Lars (2019). Anisotropic viscosity of olivine: The relationship between texture parameters and rheological behavior.
• 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.
• van Dam, Loes; Kincaid, Chris; Crameri, Fabio; Conrad, Clinton Phillips; Polkalny, R.A. & Tackley, Paul J. (2019). Laboratory and numerical models of constraints on the birth, life, and death of mantle plumes near mid-ocean ridges.
• 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).
• Weerdesteijn, Maaike; Conrad, Clinton Phillips; Selway, Kate & Ramirez, Florence (2019). MAGPIE: Magnetotelluric Analysis for Greenland and Postglacial Isostatic Evolution.
• Weerdesteijn, Maaike; Selway, Kate & Conrad, Clinton Phillips (2019). Magnetotelluric Analysis for Greenland and Postglacial Isostatic Evolution (MAGPIE).
• Conrad, Clinton Phillips (2018). Misshapen Earth: Inferring Dynamic Topography from Bathymetry & Plate Motions.
• Conrad, Clinton Phillips (2018). Water Planet: A CEED Umbrella Project.
• Conrad, Clinton Phillips (2018). Water Planet: Water's Role in the Solid Earth.
• Conrad, Clinton Phillips & Domeier, Mathew (2018). Tracing the edges of the LLSVPs in the spatial distribution of seamount volcanism.
• Crameri, Fabio; Conrad, Clinton Phillips; Montesi, L. & Lithgow-Bertelloni, C. (2018). “`Ocean-Plate Tectonics’: The importance of the mantle framework.
• Domeier, Mathew; Conrad, Clinton Phillips & Selway, K. (2018). A link between seamount volcanism and structures of the deep Earth.
• Ghosh, A.; Paul, J. & Conrad, Clinton Phillips (2018). The relation between tractions and strain rate at the base of the lithosphere: Key to understanding cratonic stability.
• Hartman, Robert; Ebbing, Jörg & Conrad, Clinton Phillips (2018). Influence of upper mantle viscosity variations on sea level change and GIA - A case study for Antarctic deglaciation models.
• Heyn, Björn Holger; Conrad, Clinton Phillips & Trønnes, Reidar G (2018). Stabilization of thermochemical piles by compositional viscosity contrasts.
• Heyn, Björn Holger; Conrad, Clinton Phillips & Trønnes, Reidar G (2018). Stabilization of thermochemical piles by compositional viscosity contrasts. EGU Gen. Assembly, EGU2018-12950.
• Karlsen, Krister Stræte; Conrad, Clinton Phillips & Magni, Valentina (2018). Deep water cycling and sea level changes on a supercontinental time scale.
• Karlsen, Krister Stræte; Conrad, Clinton Phillips & Magni, Valentina (2018). Deep water recycling and cyclic sea level change on a supercontinental time scale.
• Karlsen, Krister Stræte; Conrad, Clinton Phillips & Magni, Valentina (2018). Deep water recycling and cyclic sea level change on a supercontinental time scale.
• Kiraly, Agnes; Conrad, Clinton Phillips & Hansen, L. (2018). Geodynamic consequences of anisotropic mantle viscosity.
• Kiraly, Agnes; Conrad, Clinton Phillips & Hansen, L. (2018). Geodynamic consequences of anisotropic mantle viscosity.
• Uppalapati, Sruthi; Rolf, Tobias; Crameri, Fabio; Conrad, Clinton Phillips & Werner, Stephanie C. (2018). How Venus’ young surface came to be: New insights from 2D and 3D modelling.
• Uppalapati, Sruthi; Rolf, Tobias; Crameri, Fabio; Conrad, Clinton Phillips & Werner, Stephanie C. (2018). How Venus’ young surface came to be: New insights from 2D and 3D modelling.
• Wessel, Paul & Conrad, Clinton Phillips (2018). Absolute plate and plume motions and implications for true polar wander.
• Boudinier, G.; Wessel, P. & Conrad, Clinton Phillips (2017). Plume-spotting: Deriving the absolute motion of hotspots and plates.
• Conrad, Clinton Phillips (2017). Addressing Outstanding Problems in Deep Earth Dynamics Using Data and Models.
• Conrad, Clinton Phillips (2017). How good were the old forecasts of sea level rise?. EGU Geodynamics Blog. . doi: http://blogs.egu.eu/divisions/gd/2017/09/13/modern-day-sea-level-rise/

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