Lithosphere thickness and mantle viscosity inverted from GPS-derived deformation rates in Fennoscandia

S. Zhao*, K. Lambeck, M. Lidberg

*Corresponding author for this work

    Research output: Contribution to journalArticlepeer-review

    31 Citations (Scopus)

    Abstract

    Crustal deformation in Fennoscandia is associated with the glacial isostatic adjustment (GIA) process that is caused by ongoing stress release of the mantle after removal of the Late Pleistocene ice sheet by ~10 calka BP. With an earth model of defined structure and rheology and an ice-sheet model of known melting history, the GIA process can be simulated by geophysical models, and the surface deformation rates can be calculated and used to compare with global positioning system (GPS) observations. Therefore, the crustal deformation rates observed by GPS in Fennoscandia provide constraints on the geophysical models. On the basis of two ice sheet models (ANU-ICE and ICE-5G) reconstructed independently by the Australian National University (ANU) and University of Toronto, we use the GPS-derived deformation rates to invert for lithosphere thickness and mantle viscosity in Fennoscandia. The results show that only a three-layer earth model can be resolved from current GPS data, providing robust estimates of effective lithosphere thickness, upper and lower mantle viscosity. The earth models estimated from inversion of GPS data with two different ice sheet models define a narrow range of parameter space: the lithosphere thickness between 93 and 110 km, upper mantle viscosity between 3.4 and 5.0 × 10 20 Pas, and lower mantle viscosity between 7 × 10 21 and 13 × 10 21 Pas. The estimates are consistent with those inverted from relative sea-level indicators.

    Original languageEnglish
    Pages (from-to)278-292
    Number of pages15
    JournalGeophysical Journal International
    Volume190
    Issue number1
    DOIs
    Publication statusPublished - Jul 2012

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