The lithospheric structure of Antarctica is still underexplored. Moho depth estimate studies are in disagreement by more than 10 km in several regions, including, for example, the hinterland of the Transantarctic Mountains. Taking account the sparseness of seismological stations and the nonuniqueness of potential field methods, inversions of Moho depth are performed here based on satellite gravity data in combination with currently available seismically constrained Moho depth estimates. Our results confirm that a lower density contrast at the Moho is present under East Antarctica than beneath West Antarctica. A comparison between the Moho depth derived from our inversion and an Airy‐isostatic Moho model also reveals a spatially variable buoyancy contribution from the lithospheric mantle beneath contrasting sectors of East Antarctica. Finally, to test the plausibility of different Moho depths scenarios for the Transantarctic Mountains‐Wilkes Subglacial Basin system, we present 2‐D lithospheric models along the Trans‐Antarctic Mountain Seismic Experiment/Gamburtsev Mountain Seismic experiment seismic profile. Our models show that if a moderately depleted lithospheric mantle of inferred Proterozoic age underlies the region, then a shallower Moho is more likely beneath the Wilkes Subglacial Basin. If however, refertilization processes occurred in the upper mantle, for example, in response to Ross‐age subduction, then a deeper Moho scenario is preferred. We conclude that 3‐D lithospheric modeling, coupled with the availability of new seismic information in the hinterland of the Transantarctic Mountains, is required to help resolve this controversy, thereby also reducing the ambiguities in geothermal heat flux estimation beneath this key part of the East Antarctic Ice Sheet.

In this study we combine seismological and petrological models with satellite gravity gradient data to obtain the thermal and compositional structure of the Antarctic lithosphere. Our results indicate that Antarctica is largely in isostatic equilibrium, although notable anomalies exist. A new Antarctic Moho depth map is derived that fits the satellite gravity gradient anomaly field and is in good agreement with independent seismic estimates. It exhibits detailed crustal thickness variations also in areas of East Antarctica that are poorly explored due to sparse seismic station coverage. The thickness of the lithosphere in our model is in general agreement with seismological estimates, confirming the marked contrast between West Antarctica (<100 km) and East Antarctica (up to 260 km). Finally, we assess the implications of the temperature distribution in our model for mantle viscosities and glacial isostatic adjustment. The upper mantle temperatures we model are lower than obtained from previous seismic velocity studies. This results in higher estimated viscosities underneath West Antarctica. When combined with present‐day uplift rates from GPS, a bulk dry upper mantle rheology appears permissible.

Curvature components derived from satellite gravity gradients provide new global views of Earth’s structure. The satellite gravity gradients are based on the GOCE satellite mission and we illustrate by curvature images how the Earth is seen differently compared to seismic imaging. Tectonic domains with similar seismic characteristic can exhibit distinct differences in satellite gravity gradients maps, which points to differences in the lithospheric build-up. This is particularly apparent for the cratonic regions of the Earth. The comparisons demonstrate that the combination of seismological, and satellite gravity gradient imaging has significant potential to enhance our knowledge of Earth’s structure. In remote frontiers like the Antarctic continent, where even basic knowledge of lithospheric scale features remains incomplete, the curvature images help unveil the heterogeneity in lithospheric structure, e.g. between the composite East Antarctic Craton and the West Antarctic Rift System.

Accurate GIA models are required for correcting measurements of mass change in Antarctica and for improving knowledge of the sub-surface, especially in areas of large current ice loss such as the Amundsen Sea Embayment(ASE). Regionally, seismic and gravity data suggests lateral differences in viscosity (3D). Furthermore, mantle flow laws allow for a stress-dependent effective viscosity which changes over time (3D-s). In this study we investigate whether models with 3D/3D-s have significant effects on the uplift in the region. We use a finite element model with composite rheology consisting of diffusion and dislocation creep, forced by an ice deglaciation model starting in 1900. We use its uplift predictions as synthetic observations to test the performance of 1D model inversion in the presence of viscosity variations. Stress-dependent rheology results in lower viscosity beneath the load and a more localized uplift pattern. We demonstrate that the background stress from earlier ice load changes can both increase or decrease the influence of stress-induced effective viscosity changes. For the ASE, fitting 1D models to 3D model uplift results in a best fitting model with viscosity that represents the average of a large area, while for 3D-s rheology, local viscosity is more influential. 1D models are statistically indistinguishable from 3D/3D-s viscosity with current GPS stations. However, 3D and 3D-

This chapter describes the application and coverage of gravity and magnetic data for Antarctica with emphasis on airborne and satellite models. Low resolution satellite data help to fill gaps between high-resolution airborne data. Satellite gravity data is best used to study broad-scale lithospheric architecture while airborne data, especially magnetic data, provides finer detail. We review examples of gravity and magnetic analysis and describe the possibilities and pitfalls for estimating the properties of the lithosphere as it relates to the mantle. This is followed by a discussion on geothermal heat flow and possible ways to combine different geophysical and petrological models for a better understanding of the Antarctic mantle.

&lt;p&gt;Numerous unresolved issues exist regarding the lithosphere of Antarctica, especially in terms of its fundamental density, temperature, and compositional structure. Estimates of total lithospheric thickness typically involve assumptions on the depth of the Moho discontinuity, which remains ill-constrained in several parts of Antarctica. Recent estimates of the Moho depth from different geophysical methods show significant discrepancies of 10-20 km in large sectors of the continent. While seismological methods suffer from a limited station coverage and ice reverberation, potential field methods, such as gravity studies, are inherently non-unique. By modelling multiple geophysical parameters in a consistent way and accounting for thermodynamically stable mineral phases of rocks as a function of pressure and temperature conditions, we were able to mitigate the detrimental effects of data sparseness while also reducing geophysical inconsistencies and ambiguities. Gravity gradient data from ESA&amp;#8217;s satellite mission &amp;#8216;GOCE&amp;#8217; are used here to constrain the density distribution within the lithosphere in an integrated 3D model of the Antarctic continent. Independent seismic estimates serve as a benchmark for the robustness of our results. Our model derives new estimates of the crustal and the total lithospheric thickness of Antarctica.&lt;br&gt;Based on our new 3D lithospheric model, we investigate the feasibility of a mantle plume beneath parts of West Antarctica, which has been inferred from previous geochemistry, seismology, and glacial isostatic adjustment studies. The impact of thermal anomalies, simulating ponded plume material, on different geophysical parameters, such as geothermal heat flux, seismic velocities, mineral phase transition changes, gravity, and topographic elevation are modelled for both Marie Byrd Land and Ross Island, two key candidate sites for putative plumes. Combined interpretation of the results is performed together with current understanding of geodynamic processes, such as locations of the LLVPs at the core-mantle boundary, representing potential &amp;#8216;cradles&amp;#8217; for plumes.&lt;br&gt;Our results suggest that a deep-rooted mantle plume is unlikely beneath West Antarctica. However, the observed low seismic velocity zones could still correspond to proposed hot upper mantle zones characterised by lower viscosity. Alternative/additional explanations, such compositional effects and water content as causes for the seismic anomalies must also be further evaluated to better assess their effects on mantle viscosities. This is particularly important beneath regions of recent ice mass loss and recently observed remarkably high rates of GIA-induced bedrock uplift, such as the Amundsen Sea Embayment.&lt;/p&gt;

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Die geophysikalischen Eigenschaften der Erdkruste und des Erdmantels unter dem Kontinent Antarktika sind noch immer relativ schlecht erforscht. Mithilfe von Satellitendaten des Gravitationsfelds der Erde konnten nun Dichte‐ und Temperaturverteilung unterhalb der Antarktis neu abgeschätzt werden. Die Ergebnisse helfen unter anderem dazu, Ausgleichsbewegungen der festen Erde als Reaktion auf Eismassenveränderungen besser zu modellieren.