Mantle and sub-lithosphere mantle gravity maps from the LITHO1.0 global lithospheric model

Tenzer, Róbert; Chen, Wenjin

doi:10.1016/j.earscirev.2019.05.001

Cited by 25 publications

(9 citation statements)

References 179 publications

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“…The final residual anomalies (Figure d) are obtained by removing all these effects from the Bouguer gravity disturbances (Figure d). We note that the lower boundary for the crustal density correction is the Moho boundary; therefore, any change of the Moho would have an effect on the crystalline crust correction (Tenzer & Chen, ). Therefore, we performed an iterative procedure to take into account possible changes of the Moho.…”

Section: Moho Structure Of the Tibetan Plateaumentioning

confidence: 99%

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Moho Beneath Tibet Based on a Joint Analysis of Gravity and Seismic Data

Zhao

Liu

Chen

et al. 2020

Geochem Geophys Geosyst

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We use the improved Parker‐Oldenburg's formulas that include a reference depth into the exponential term and employ the Gauss‐fast Fourier transform method to determine Moho depth beneath the Tibetan Plateau. The synthetic models demonstrate that the improved Parker's formula has high accuracy with the maximum absolute error less than 0.25 mGal compared to the analytical solution. Two inversion parameters, that is, the reference depth and the density contrast, are essential for the Moho estimation based on the gravity field, and they need to be determined in advance to obtain correct results. Therefore, the Moho estimates derived from existing seismic studies are used to reduce the nonuniqueness of the gravity inversion and to determine these parameters by searching for the maximum correlation between the gravity‐inverted and seismic‐derived Moho depths. Another critical issue is to remove beforehand the gravity effects of other factors, which affect the observed gravity field besides Moho variations. In addition to the topography, the gravity effects of the sedimentary layer and crystalline crust are removed based on existing crustal models, while the upper mantle impact is determined based on the seismic tomography model. The inversion results show that the Moho structure under the Tibetan plateau is very complex with the depths varying from about 30–40 km in the surrounding basins (e.g., Ganges basin, Sichuan basin, and Tarim basin) to 60–80 km within the plateau. This considerable difference up to 40 km on the Moho depth reveals the substantial uplift and thickening of the crust in the Tibetan Plateau. Furthermore, two visible “Moho depression belts” are observed within the plateau with the maximum Moho deepening along the Indus‐Tsangpo Suture and along the northern margin of Tibet bounding the Tarim basin with the relatively shallow Moho in central Tibet between them. The southern “belt” is likely formed in compressional environment, where the Indian plate underthrusts northward beneath the Tibetan Plateau, while the northern one could be formed by the southward underthrust of the Asian lithosphere beneath Tibet.

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Section: Moho Structure Of the Tibetan Plateaumentioning

confidence: 99%

“…Geochemistry, Geophysics, Geosystems the crustal density correction is the Moho boundary; therefore, any change of the Moho would have an effect on the crystalline crust correction (Tenzer & Chen, 2019). Therefore, we performed an iterative procedure to take into account possible changes of the Moho.…”

Section: 1029/2019gc008849mentioning

confidence: 99%

Moho Beneath Tibet Based on a Joint Analysis of Gravity and Seismic Data

Zhao

Liu

Chen

et al. 2020

Geochem Geophys Geosyst

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“…2). For the oceanic crust, we use a reference thickness of 6.5 km and a reference density of 2900 kg/m 3 that results in an average oceanic crustal density of ∼ 2875 kg/m 3 at the MOR considering the effect of thermal expansion, in agreement with global estimates (e.g., Carlson and Raskin, 1984;Tenzer and Chen, 2019). For the mantle, we use the density as a function of depth at the spreading mid-ocean ridge extracted from the 2-D thermo-mechanical model M1 that is coupled to the thermodynamic solution based on the reference fertile mantle composition SP2008.…”

Section: Definition Of Two Reference Columnsmentioning

confidence: 69%

Relative continent/mid-ocean ridge elevation: a reference case for isostasy in geodynamics

Theunissen¹,

Huismans²,

Lü³

et al. 2022

Preprint

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<p>The choice of crustal and mantle densities in numerical geodynamic models is usually based on convention. The isostatic component of the topography is, however, in most if not all cases not calibrated to fit observations resulting in not very well constrained elevations. The density distribution on Earth is not easy to constrain because it involves multiple variables (temperature, pressure, composition, and deformation). We provide a review and global analysis of the topography of the Earth showing that elevation of stable continents and active mid-ocean ridges far from hotspots on average is +400 m and -2750 m respectively. We show that density values for the crust and mantle, commonly used for isostatic modeling result in highly inaccurate prediction of topography. We use thermodynamic calculations to constrain the density distribution of the continental lithospheric mantle, sub-lithospheric mantle, the mid-ocean ridge mantle, and review data on crustal density. We couple the thermo-dynamic consistent density calculations with 2-D forward geodynamic modelling including melt prediction and calibrate crustal and mantle densities that match the observed elevation difference. Our results can be used as a reference case for geodynamic modeling that accurately fits the relative elevation between continents and mid-ocean ridges consistent with geophysical observations and thermodynamic calculations.&#160;</p>

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“…We note that regional maps of individual gravity and gravity gradient corrections as well as intermediate results obtained after applying these corrections to observed gravity disturbances and vertical gravity gradient values are not presented here. Tenzer and Chen (2019) presented and interpreted globally these gravity corrections and step‐wise corrected gravity disturbances, and Novák and Tenzer (2013) conducted a similar study for the gravity gradient.…”

Section: Numerical Realizationmentioning

confidence: 99%

Moho Depth Estimation Beneath Tibet From Satellite Gravity Data Based on a Condensation Approach

Chen

Tenzer

et al. 2021

Earth and Space Science

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We develop an algorithm for a Moho depth recovery from gravity and gravity gradiometry data and apply this method to estimate the Moho depth beneath the Tibetan Plateau. The basic idea of this algorithm is to describe mathematically the Moho depth undulations in terms of a condensation layer with respect to a mean Moho depth, instead of applying more commonly used isostatic compensation schemes. Expressions that functionally relate gravity field quantities with a (Moho) condensation layer are derived in spectral and spatial domains. The main advantage of this algorithm is that a functional relation between gravity field quantities and surface density anomalies, and consequently Moho depth undulations has a linear form. The proposed algorithm is tested using satellite gravity and gravity gradiometry data. The Moho depth (taken with respect to the geoid surface) estimates obtained based on applying this algorithm are validated against global and regional seismic Moho results at the study area of Tibet. We also compare the result with the corresponding Moho depth estimates obtained by applying the Parker-Oldenburg and Vening Meinesz-Moritz's (VMM) methods. The validation shows that results from all three gravimetric methods are similar, and they also closely agree with a regional seismic Moho model. Nevertheless, the VMM method and our algorithm in this comparison over-perform the Parker-Oldenburg's method. The analysis of results also reveals that the newly developed algorithm provides better result (in terms of the RMS fit with a regional seismic Moho model) when applied for a Moho determination from gravity gradiometry instead of gravity data.

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Mantle and sub-lithosphere mantle gravity maps from the LITHO1.0 global lithospheric model

Cited by 25 publications

References 179 publications

Moho Beneath Tibet Based on a Joint Analysis of Gravity and Seismic Data

Moho Beneath Tibet Based on a Joint Analysis of Gravity and Seismic Data

Relative continent/mid-ocean ridge elevation: a reference case for isostasy in geodynamics

Moho Depth Estimation Beneath Tibet From Satellite Gravity Data Based on a Condensation Approach

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