TY - JOUR
T1 - Lithosphere thickness and mantle viscosity inverted from GPS-derived deformation rates in Fennoscandia
AU - Zhao, S.
AU - Lambeck, K.
AU - Lidberg, M.
PY - 2012/7
Y1 - 2012/7
N2 - 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.
AB - 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.
KW - Rheology: mantle
KW - Space geodetic surveys
KW - Tectonics and climactic interactions
KW - Transient deformation
UR - http://www.scopus.com/inward/record.url?scp=84862238098&partnerID=8YFLogxK
U2 - 10.1111/j.1365-246X.2012.05454.x
DO - 10.1111/j.1365-246X.2012.05454.x
M3 - Article
SN - 0956-540X
VL - 190
SP - 278
EP - 292
JO - Geophysical Journal International
JF - Geophysical Journal International
IS - 1
ER -