Density structure of the mantle transition zone and the dynamic geoid

Kaban, Mikhail K.; Trubitsyn, V. P.

doi:10.1016/j.jog.2012.02.007

Cited by 14 publications

(12 citation statements)

References 50 publications

(99 reference statements)

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“…[21] Density variations are calculated using standard velocity-to-density scaling factor ¼ 0.2 (equation (19)), which is generally consistent with the mineral physics estimations and previous studies [e.g., Karato, 1993;Mitrovica and Forte, 2004;Steinberger and Calderwood, 2006;Kaban and Trubitsyn, 2012]. These are applied to the S40RTS model [Ritsema et al, 2011] as follows:…”

Section: Effects Of Lvv On the Geoidmentioning

confidence: 99%

Revising the spectral method as applied to modeling mantle dynamics

Petrunin

Kaban

Rogozhina

et al. 2013

Geochem Geophys Geosyst

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[1] The observed geoid, dynamic topography, and surface plate velocities are controlled by various factors such as density and viscosity variations in the Earth's mantle and strength of the lithosphere. Previous studies have shown that the geoid signal cannot be resolved in details within the framework of a simplified model of the mantle flow considering only radial viscosity variations. Thus, a modeling technique handling both radial and lateral variations of viscosity and other parameters should be used. The spectral method provides a high-accuracy semianalytical solution of the Navier-Stokes and Poisson equations when viscosity is only depth (radially) dependent. In this study, we present the numerical approach, built up on the substantially revised method originally proposed by Zhang and Christensen (1993), for solving the Navier-Stokes equation in the spectral domain with lateral variations of viscosity (LVV). This approach incorporates a number of numerical algorithms providing efficient calculations of the instantaneous Stokes flow in the sphere and taking into account the effects of LVV, self gravitation, and compressibility. In contrast to the traditionally used propagator method, our approach suggests a continuous integration over depth without introducing internal interfaces. Various numerical tests have been employed to test accuracy and efficiency of the proposed technique. Benchmarking of the code shows its ability to solve the mantle convection problems implying strong LVV with high resolution.Components: 16,999 words, 5 figures.

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Section: Effects Of Lvv On the Geoidmentioning

confidence: 99%

Revising the spectral method as applied to modeling mantle dynamics

Petrunin

Kaban

Rogozhina

et al. 2013

Geochem Geophys Geosyst

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show abstract

“…[]. In addition, we remove the effects of the transition zone boundaries, as determined by Kaban and Trubitsyn []. The total gravity effect of the mantle density heterogeneities below 325 km is shown in Figure a.…”

Section: Residual Mantle Gravity Anomalies and Residual Topographymentioning

confidence: 99%

“…In the first stage the crustal effect is removed from the Bouguer gravity anomalies and topography. Furthermore, the effect of deep heterogeneity of the Earth is reduced using recent global dynamic models [ Kaban and Trubitsyn , ; Petrunin et al ., ]. The calculated residuals reflect the effect of the upper mantle density variations.…”

Section: Introductionmentioning

confidence: 99%

Three‐dimensional density model of the upper mantle in the Middle East: Interaction of diverse tectonic processes

et al. 2016

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We present a three‐dimensional density model of the lithosphere and upper mantle for the Middle East and surroundings based on seismic, gravity, and seismic tomography data and analyze the main factors responsible for the density variations. The gravity effect of the crust is calculated and removed from the observed field using the most recent crustal model. The residual gravity anomalies are jointly inverted with the residual topography to image the density distribution within the upper mantle. The inversion is constrained by an initial density model based on seismic tomography. The obtained density variations span in a large range (±60 kg/m3), revealing strong asymmetry in the density structure of the Arabian plate. The uppermost mantle layer in the Arabian Shield is relatively dense. However, below a depth of ~100 km we observe a strong low‐density anomaly. In contrast, the mantle density in the Arabian platform increases at the same depths. The most pronounced decrease of the mantle density occurs in the Gulf of Aden, Red Sea, and East African Rift. Underneath the northern Red Sea the low‐density anomaly is limited to the depth ~150 km, while in the southern part it is likely linked to a mantle plume. The densest mantle material is found under the South Caspian basin, which is likely associated with an eclogite body in the uppermost mantle. In the collision zones (the Zagros Belt and the Hellenic Arc), the high‐density lithosphere shows the location of the subducting plates.

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“…In this study, we employed the same global dynamic model used by Kaban et al [2015aKaban et al [ , 2016, which provides the effects of deep density anomalies below 325 km (bottom of the upper mantle model in this study). This model includes the effect of lateral variations of viscosity, weak plate boundaries, and the density variation related to the phase transition boundaries [Kaban and Trubitsyn, 2012;Petrunin et al, 2013;Kaban et al, 2014a]. More details on these calculations and maps of the gravity field and dynamic topography, induced by the density heterogeneity below 325 km, are provided in the supporting information [Gu et al, 2003;Kaban et al, 2014a;Flament et al, 2013].…”

Section: Mantle Gravity Anomalies and Residual Topographymentioning

confidence: 99%

3D density model of the upper mantle of Asia based on inversion of gravity and seismic tomography data

Kaban

Stolk

Tesauro

et al. 2016

Geochem Geophys Geosyst

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We construct a new-generation 3D density model of the upper mantle of Asia and its surrounding areas based on a joint interpretation of several data sets. A recent model of the crust combining nearly all available seismic data is employed to calculate the impact of the crust on the gravity anomalies and observed topography and to estimate the residual mantle anomalies and residual topography. These fields are jointly inverted to calculate the density variations in the lithosphere and upper mantle down to 325 km.As an initial approximation, we estimate density variations using a seismic tomography model. Seismic velocity variations are converted into temperatures and then to density variations based on mineral physics constraints. In the Occam-type inversion, we fit both the residual mantle gravity anomalies and residual topography by finding deviations to the initial model. The obtained corrections improve the resolution of the initial model and reflect important features of the mantle structure that are not well resolved by the seismic tomography. The most significant negative corrections of the upper mantle density, found in the Siberian and East European cratons, can be associated with depleted mantle material. The most pronounced positive density anomalies are found beneath the Tarim and South Caspian basins, Barents Sea, and Bay of Bengal. We attribute these anomalies to eclogites in the uppermost mantle, which have substantially affected the evolution of the basins. Furthermore, the obtained results provide evidence for the presence of eclogites in the oceanic subducting mantle lithosphere.

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Density structure of the mantle transition zone and the dynamic geoid

Cited by 14 publications

References 50 publications

Revising the spectral method as applied to modeling mantle dynamics

Revising the spectral method as applied to modeling mantle dynamics

Three‐dimensional density model of the upper mantle in the Middle East: Interaction of diverse tectonic processes

3D density model of the upper mantle of Asia based on inversion of gravity and seismic tomography data

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