Models of isostatic and dynamic topography, geoid anomalies, and their uncertainties

Panasyuk, Svetlana; Hager, Bradford H.

doi:10.1029/2000jb900249

Cited by 89 publications

(96 citation statements)

References 30 publications

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“…For oceanic areas our residual topography map is close to the previously published one [25] and to the map of Panasyuk and Hager [26] based upon the cooling plate model. However, the di¡erences on continents are substantial.…”

Section: Mantle Gravity and Residual Topographysupporting

confidence: 59%

“…This is especially true for North America and Eurasia where, contrary to our previous calculations, the crustal model is now based on high-resolution (mostly) seismic data, rather than the global model. It is also important to note that at this stage we do not apply any correction for the subcrustal continental tectosphere, as was done by Panasyuk and Hager [26].…”

Section: Mantle Gravity and Residual Topographymentioning

confidence: 99%

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Density of the continental roots: compositional and thermal contributions

Kaban

Schwintzer

Artemieva

et al. 2003

Earth and Planetary Science Letters

170

134

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The origin and evolution of cratonic roots has been debated for many years. Precambrian cratons are underlain by cold lithospheric roots that are chemically depleted. Thermal and petrologic data indicate that Archean roots are colder and more chemically depleted than Proterozoic roots. This observation has led to the hypothesis that the degree of depletion in a lithospheric root depends mostly on its age. Here we test this hypothesis using gravity, thermal, petrologic, and seismic data to quantify differences in the density of cratonic roots globally. In the first step in our analysis we use a global crustal model to remove the crustal contribution to the observed gravity. The result is the mantle gravity anomaly field, which varies over cratonic areas from 3100 to +100 mGal. Positive mantle gravity anomalies are observed for cratons in the northern hemisphere: the Baltic shield, East European Platform, and the Siberian Platform. Negative anomalies are observed over cratons in the southern hemisphere: Western Australia, South America, the Indian shield, and Southern Africa. This indicates that there are significant differences in the density of cratonic roots, even for those of similar age. Root density depends on temperature and chemical depletion. In order to separate these effects we apply a lithospheric temperature correction using thermal estimates from a combination of geothermal modeling and global seismic tomography models. Gravity anomalies induced by temperature variations in the uppermost mantle range from 3200 to +300 mGal, with the strongest negative anomalies associated with mid-ocean ridges and the strongest positive anomalies associated with cratons. After correcting for thermal effects, we obtain a map of density variations due to lithospheric compositional variations. These maps indicate that the average density decrease due to the chemical depletion within cratonic roots varies from 1.1% to 1.5%, assuming the chemical boundary layer has the same thickness as the thermal boundary layer. The maximal values of the density drop are in the range 1.7^2.5%, and correspond to the Archean portion of each craton. Temperatures within cratonic roots vary strongly, and our analysis indicates that density variations in the roots due to temperature are larger than the variations due to chemical differences. ß

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Section: Mantle Gravity and Residual Topographysupporting

confidence: 59%

Section: Mantle Gravity and Residual Topographymentioning

confidence: 99%

Density of the continental roots: compositional and thermal contributions

Kaban

Schwintzer

Artemieva

et al. 2003

Earth and Planetary Science Letters

170

134

View full text Add to dashboard Cite

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“…Some important aspects of such an error analysis have been addressed by Panasyuk and Hager (2000) and Kaban and Schwintzer (2001). The overall error derives from uncertainties in: (1) the measured gravity and (2) the estimated thickness and density of (a) the sediment; (b) the crystalline basement; (c) the upper crust; (d) the lower crust; and (e) the mantle lid.…”

Section: Appraisal Of Model Uncertaintiesmentioning

confidence: 99%

Mantle origin of the Emeishan large igneous province (South China) from the analysis of residual gravity anomalies

Deng

Zhang

Mooney

et al. 2014

Lithos

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“…For Flament et al (2013), it is situated between latitudes 15 • S and 15 • N, for Panasyuk and Hager (2000), between latitudes 20 • S and 15 • N, for Steinberger (2007) between latitudes 20 • S and 10 • N, for Braun (2010) between latitudes 25 • S and 10 • N, and for Winterbourne et al (2014), between latitudes 25 • S and 25 • N, which is roughly the latitude range we find here. In the same way, the ridge depression in the Indian Ocean, along the Australia-Antarctica Discordance (AAD) appears in all residual topography studies (Kido and Seno, 1994;Panasyuk and Hager, 2000;Kaban et al, 2003;Braun, 2010;Flament et al, 2013;Winterbourne et al, 2014). Our study also points out a relatively shallow seafloor in the vicinity of the Azores and Iceland, in the North Atlantic ocean, respectively at latitudes 40 • N and 65 • N, which is coherent with the high residual topography found by Kido and Seno (1994) and Winterbourne et al (2014).…”

Section: Subsidence Parametersmentioning

confidence: 60%

Variation of the subsidence parameters, effective thermal conductivity, and mantle dynamics

Adam

King

Vidal

et al. 2015

Earth and Planetary Science Letters

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Available online xxxx Editor: P. Shearer Keywords: seafloor subsidence subsidence rate ridge depth effective thermal conductivity mantle dynamics dynamic topographyThe subsidence of young seafloor is generally considered to be a passive phenomenon related to the conductive cooling of the lithosphere after its creation at mid-oceanic ridges. Recent alternative theories suggest that the mantle dynamics plays an important role in the structure and depth of the oceanic lithosphere. However, the link between mantle dynamics and seafloor subsidence has still to be quantitatively assessed. Here we provide a statistical study of the subsidence parameters (subsidence rate and ridge depth) for all the oceans. These parameters are retrieved through two independent methods, the positive outliers method, a classical method used in signal processing, and through the MiFil method. From the subsidence rate, we compute the effective thermal conductivity, k eff , which ranges between 1 and 7 Wm −1 K −1 . We also model the mantle flow pattern from the S40RTS tomography model. The density anomalies derived from S40RTS are used to compute the instantaneous flow in a global 3D spherical geometry. We show that departures from the k eff = 3 Wm −1 K −1 standard value are systematically related to mantle processes and not to lithospheric structure. Regions characterized by k eff > 3 W m −1 K −1 are associated with mantle uplifts (mantle plumes or other local anomalies). Regions characterized by k eff < 3 W m −1 K −1 are related to large-scale mantle downwellings such as the Australia-Antarctic Discordance (AAD) or the return flow from the South Pacific Superswell to the East Pacific Rise. This demonstrates that mantle dynamics plays a major role in the shaping of the oceanic seafloor. In particular, the parameters generally considered to quantify the lithosphere structure, such as the thermal conductivity, are not only representative of this structure but also incorporate signals from the mantle convection occurring beneath the lithosphere. The dynamic topography computed from the S40RTS tomography model reproduces the subsidence pattern observed in the bathymetry. Overall we find a good correlation between the subsidence parameters derived from the bathymetry and the dynamic topography. This demonstrates that these parameters are strongly dependent on mantle dynamics.

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Models of isostatic and dynamic topography, geoid anomalies, and their uncertainties

Cited by 89 publications

References 30 publications

Density of the continental roots: compositional and thermal contributions

Density of the continental roots: compositional and thermal contributions

Mantle origin of the Emeishan large igneous province (South China) from the analysis of residual gravity anomalies

Variation of the subsidence parameters, effective thermal conductivity, and mantle dynamics

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