Analysis of the Refined CRUST1.0 Crustal Model and its Gravity Field

Tenzer, Róbert; Chen, Wenjin; Tsoulis, Dimitrios; Bagherbandi, Mohammad; Sjöberg, Lars E.; Novák, Pavel; Jin, Shuanggen

doi:10.1007/s10712-014-9299-6

Cited by 99 publications

(37 citation statements)

References 78 publications

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“…Although the gravity effects of the sedimentary and crystalline crust layers have been removed from the Bouguer gravity anomalies in the studies of Baranov et al () and Chen and Tenzer (), these studies did not remove the gravity effect of the mass anomalies in the upper mantle, which is significant with the amplitude reaching 300 mGal (Figure c). Thus, the persisting gravitational signal of mantle heterogeneities could introduce large systematic bias into the gravimetric Moho determinations (Tenzer, Chen, Tsoulis, et al, ). Also, the gravity effect of the crystalline crust estimated in these studies is based on the model CRUST1.0, which provides extremely low resolution for these parameters.…”

Section: Moho Structure Of the Tibetan Plateaumentioning

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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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%

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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“…The gravity corrections applied in Equation 2were computed using the following generalized expression [70][71][72]:…”

Section: Bouguer Gravity Datamentioning

confidence: 99%

Combined Gravimetric-Seismic Moho Model of Tibet

2018

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Substantial progress has been achieved over the last four decades to better understand a deep structure in the Himalayas and Tibet. Nevertheless, the remoteness of this part of the world still considerably limits the use of seismic data. A possible way to overcome this practical restriction partially is to use products from the Earth’s satellite observation systems. Global topographic data are provided by the Shuttle Radar Topography Mission (SRTM). Global gravitational models have been derived from observables delivered by the gravity-dedicated satellite missions, such as the Gravity Recovery and Climate Experiment (GRACE) and the Gravity field and steady-state Ocean Circulation Explorer (GOCE). Optimally, the topographic and gravity data should be combined with available results from tomographic surveys to interpret the lithospheric structure, including also a Moho relief. In this study, we use seismic, gravity, and topographic data to estimate the Moho depth under orogenic structures of the Himalayas and Tibet. The combined Moho model is computed based on solving the Vening Meinesz–Moritz (VMM) inverse problem of isostasy, while incorporating seismic data to constrain the gravimetric solution. The result of the combined gravimetric-seismic data analysis exhibits an anticipated more detailed structure of the Moho geometry when compared to the solution obtained merely from seismic data. This is especially evident over regions with sparse seismic data coverage. The newly-determined combined Moho model of Tibet shows a typical contrast between a thick crustal structure of orogenic formations compared to a thinner crust of continental basins. The Moho depth under most of the Himalayas and the Tibetan Plateau is typically within 60–70 km. The maximum Moho deepening of ~76 km occurs to the south of the Bangong-Nujiang suture under the Lhasa terrane. Local maxima of the Moho depth to ~74 km are also found beneath Taksha at the Karakoram fault. This Moho pattern generally agrees with the findings from existing gravimetric and seismic studies, but some inconsistencies are also identified and discussed in this study.

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“…We used 449 the BEDMAP2 data to compute the ice stripping gravity correction (see Tenzer et al 2015) 450 for the glacial density of 917 kg m -3 (Cutnell and Kenneth 1995). The sediment stripping 451 gravity correction was evaluated using the CRUST1.0 sediment data (for continental 452 sedimentary basins outside of Antarctica), a new seismic sediment model for Antarctica 453 (Fig.…”

Section: U N C O R R E C T E D P R O O Fmentioning

confidence: 99%

“…Tenzer et al (2015) 412 demonstrated that the application of these gravity corrections yields the refined (Bouguer) 413 gravity data that have a high spatial correlation with the Moho geometry. However, these 414 gravity data still comprise the gravitational signal of (unmodeled) mantle density hetero-415 geneities as well as errors due to crustal model uncertainties.…”

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confidence: 99%