Estimating the effective elastic thickness of the Arctic lithosphere using the wavelet coherence method: Tectonic implications

Ji, Fei; Zhang, Qiao; Xu, Mingju; Zhou, Xiwen; Guan, Qingsheng

doi:10.1016/j.pepi.2021.106770

Cited by 5 publications

(1 citation statement)

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“…Also, the asymmetric nature of the low harmonic terms of order 0 is exceedingly large, resulting in large positive anomalies around the arctic circle and large negative ones around the south pole. We also note that the geoid variation across the Arctic basin and the northern Russian platform is much larger than that expected from its isostatic state and lithospheric structure (Ji et al, 2021;Lebedeva-Ivanova et al, 2019;Pease et al, 2014).…”

Section: The Residual Upper Mantle Geoidmentioning

confidence: 68%

The Upper Mantle Geoid for Lithospheric Structure and Dynamics

Salajegheh,

Afonso

2023

JGR Solid Earth

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Geoid anomalies offer crucial information on the internal density structure of the Earth, and thus, on its constitution and dynamic state. In order to interpret geoid undulations in terms of depth, magnitude and lateral extension of density anomalies in the lithosphere and upper mantle, the effects of lower mantle density anomalies need to be removed from the full geoid (thus obtaining the residual ’upper mantle geoid’). However, how to achieve this seemingly simple filtering exercise has eluded consensus for decades in the solid Earth community. While there is wide agreement regarding the causative masses of degrees > 10 in spherical harmonic expansions of the upper mantle geoid, those contributing to degrees < 7‐8 remain ambiguous. Here we use spherical harmonic analysis and recent tomography and density models from joint seismic‐geodynamic inversions to derive a representative upper mantle geoid, including the contributions from low harmonic degrees. We show that the upper mantle geoid contains important contributions from degrees 5 and 6 and interpret the causative masses as arising from the coupling between the long‐wavelength lithospheric structure and the sublithospheric upper mantle convection pattern. Importantly, the contributions from degrees 3 < l < 8 do not show a simple power‐law behaviour (e.g. Kaula’s rule), which precludes the use of standard filtering techniques in the spectral domain. Our upper mantle geoid model will be useful in studies of i) lithospheric structure, ii) dynamic topography and mantle viscosity, iii) lithosphere‐asthenosphere interactions and iv) the global stress field within the lithosphere and its associated hazards.

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Section: The Residual Upper Mantle Geoidmentioning

confidence: 68%