Open AccessUpwelling plumes, superswells and true polar wander
Author(s) -
GreffLefftz Marianne
Publication year - 2004
Publication title -
geophysical journal international
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.302
H-Index - 168
eISSN - 1365-246X
pISSN - 0956-540X
DOI - 10.1111/j.1365-246x.2004.02440.x
Subject(s) - geology , geophysics , mantle (geology) , upwelling , doming , plume , polar , geodesy , seismology , physics , tectonics , meteorology , oceanography , astronomy
SUMMARY The geological evolution of the rotational axis of the Earth is most likely controlled by internal mass redistribution within the mantle. Palaeomagnetic observations suggest that it is episodic in nature, with periods of quasi‐standstill alternating with periods of faster wander. Here, we investigate two models for the influence of mantle plumes that vary at different spatial wavelengths on the time variations of the rotational axis (true polar wander; TPW). In the first model, we represent an upwelling plume as a sphere whose radius varies as a function of the flux of material in the conduit and that traverses the mantle at the Stokes velocity. Such a plume produces very little wander of the rotational axis. We then study the effects of two superswells that mimic the ones observed with seismic tomography and conclude that a doming regime within the mantle involves significant polar wander. Some of the features of this TPW that are directly linked to the periodicity of doming are reminiscent of observed phases of slow and fast TPW, with similar peak velocities.