Using postglacial sea level, crustal velocities and gravity-rate-of-change to constrain the influence of thermal effects on mantle lateral heterogeneities

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	Using postglacial sea level, crustal velocities and gravity-rate-of-change to constrain the influence of thermal effects on mantle lateral heterogeneities
	Wang, Hansheng ; Wu, Patrick ; van der Wal, Wouter
刊名	Journal of Geodynamics
	2008
期号	3-5 页码:104-117
中文摘要	Lateral heterogeneities in the mantle can be caused by thermal, chemical and non-isotropic pre-stress effects. Here, we investigate the possibility of using observations of the glacial isostatic adjustment (GIA) process to constrain the thermal contribution to lateral variations in mantle viscosity. in particular, global historic relative sea level, GPS in Laurentide and Fennoscandia, altimetry together with tide-gauge data in the Great Lakes area, and GRACE data in Laurentide are used. The lateral viscosity perturbations are inferred from the seismic tomography model S2OA by inserting the scaling factor to determine the contribution of thermal effects versus compositional heterogeneity and non-isotropic pre-stress effects on lateral heterogeneity in mantle viscosity. When beta=1, lateral velocity variations are caused by ther- mal effects alone. With beta<1, the contribution of thermal effect decreases, so that for beta=0, there is no lateral viscosity variation and the Earth is laterally homogeneous. These lateral viscosity variations are superposed on four different reference models which differ significantly in the lower mantle viscosity. The Coupled Laplace Finite Element method is used to predict the GIA response on a spherical, self-gravitating, compressible, viscoelastic Earth with self-gravitating oceans, induced by the ICE-4G deglaciation model. Results show that the effect of on uplift rates and gravity rate-of-change is not simple and involves the trade-off between the contribution of lateral viscosity variations in the transition zone and in the lower mantle. Models with small viscosity contrast in the lower mantle cannot explain the observed uplift rates in Laurentide and Fennoscandia. However, the RF3S20 model with a reference viscosity profile simplified from Peltier's VM2 with the Value of P around 0.2-0.4 is found to explain most of the global RSL data, the uplift rates in Laurentide and Fennoscandia and the BIFROST horizontal velocity data. In addition, the changes in GIA signals caused by changes in the value of beta are large enough to be detected by the data, although uncertainty in other parameters in the GIA models still exists. This may encourage us to further utilize GIA observations to constrain the thermal effect on mantle lateral heterogeneity as geodetic and satellite gravity measurements are improved. (C) 2008 Published by Elsevier Ltd.
原文出处	://WOS:000260360800005
公开日期	2012-04-11
内容类型	期刊论文
源URL	[http://ir.whigg.ac.cn/handle/342008/3297]
专题	测量与地球物理研究所_其他_期刊论文
推荐引用方式 GB/T 7714	Wang, Hansheng,Wu, Patrick,van der Wal, Wouter. Using postglacial sea level, crustal velocities and gravity-rate-of-change to constrain the influence of thermal effects on mantle lateral heterogeneities[J]. Journal of Geodynamics,2008(3-5):104-117.
APA	Wang, Hansheng,Wu, Patrick,&van der Wal, Wouter.(2008).Using postglacial sea level, crustal velocities and gravity-rate-of-change to constrain the influence of thermal effects on mantle lateral heterogeneities.Journal of Geodynamics(3-5),104-117.
MLA	Wang, Hansheng,et al."Using postglacial sea level, crustal velocities and gravity-rate-of-change to constrain the influence of thermal effects on mantle lateral heterogeneities".Journal of Geodynamics .3-5(2008):104-117.