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Han, Shunjie, Yuan, Tao, Mao, Wei, and Zhong, Shijie, 2024. The persisting conundrum of mantle viscosity inferred from mantle convection and glacial isostatic adjustment processes. Earth and Planetary Science Letters, 648:119069, doi:10.1016/j.epsl.2024.119069.
• from the NASA Astrophysics Data System • by the DOI System •
@ARTICLE{2024EPSL.64819069H,
author = {{Han}, Shunjie and {Yuan}, Tao and {Mao}, Wei and {Zhong}, Shijie},
title = "{The persisting conundrum of mantle viscosity inferred from mantle convection and glacial isostatic adjustment processes}",
journal = {Earth and Planetary Science Letters},
keywords = {Mantle viscosity, Glacial Isostatic Adjustment, Mantle Convection, The Earth's Geoid Anomalies},
year = 2024,
month = dec,
volume = {648},
eid = {119069},
pages = {119069},
abstract = "{Mantle viscosity exerts important controls on the long-term (i.e.,
>10<SUP loc=``post''>6</SUP> years) dynamics of the mantle and
lithosphere and the short-term (i.e., 10 to 10<SUP
loc=``post''>4</SUP> years) crustal motion induced by loading
forces including ice melting, sea-level changes, and
earthquakes. However, mantle viscosity structures inferred from
modeling observations associated with mantle dynamic and loading
processes may differ significantly and remain a hotly debated
topic over recent decades. In this study, we investigate the
effects of mantle viscosity structures on observations of the
geoid, mantle structures, and present-day crustal motions and
time-varying gravity by considering five representative mantle
viscosity structures in models of mantle convection and glacial
isostatic adjustment (GIA). These five viscosity models fall
into two categories: 1) two viscosity models derived from
modeling the geoid in mantle convection models with
{\ensuremath{\sim}}100 times more viscous lower mantle than the
upper mantle, and 2) the other three with less viscosity
increase from the upper to lower mantles that are derived from
modeling the late Pleistocene and Holocene relative sea level
changes and other observations in GIA models. Our convection
models use the plate motion history for the last 130 Myrs as the
surface boundary conditions and depth- and temperature-dependent
viscosity to predict the present-day convective mantle structure
of subducted slabs and the intermediate wavelength (degrees
4{\textendash}12) geoid. Our GIA models using different ice
history models (e.g., ICE-6 G and ANU) compute the GIA-induced
present-day crustal motions and time-varying gravity. Our
calculations demonstrate that while the viscosity models with a
higher viscosity in the lower mantle ({\ensuremath{\sim}}2
{\texttimes} 10<SUP loc=``post''>22</SUP> Pa<SUP
loc=``post''>.</SUP>s) reproduce the degrees 4{\textendash}12
geoid and seismic slab structures, they significantly over-
predict the geodetic (i.e., GPS and GRACE) observations of
crustal motions and time varying gravity. Our calculations also
show that while two viscosity models derived from fitting the
RSL data with averaged mantle viscosity of
{\ensuremath{\sim}}10<SUP loc=``post''>21</SUP> Pa<SUP
loc=``post''>.</SUP>s for the top 1200 km of the mantle
reproduce well the geodetic observations independent of ice
models, they fail to explain the geoid and seismic slab
structures. Therefore, our study highlights the persisting
conundrum of mantle viscosity structures derived from different
observations. We also discuss a number of possible ways
including transient, stress-dependent and 3-D viscosity to
resolve this important issue in Geodynamics.}",
doi = {10.1016/j.epsl.2024.119069},
adsurl = {https://ui.adsabs.harvard.edu/abs/2024E&PSL.64819069H},
adsnote = {Provided by the SAO/NASA Astrophysics Data System}
}
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