The rotational stability of a convecting earth

Assessing inferences of rapid TPW in the late cretaceous

N. H. Chan, J. X. Mitrovica, Isamu M Matsuyama, J. R. Creveling, S. Stanley

Research output: Contribution to journalArticle

9 Citations (Scopus)

Abstract

We outline a linearized rotational stability theory for predicting the time dependence of true polar wander (TPW) on a Maxwell viscoelastic body in response to mantle convective loading. The new theory is based on recent advances in ice age rotation theory. A comparison between predictions based on the new theory and analytic expressions for equilibrium (infinite-time) TPW on planetary models with elastic lithospheres demonstrates that the linearized theory can, in the case of loading at mid-latitudes, predict TPW of over 20° to better than 5 per cent accuracy. We present predictions of TPW for loading with periodic and net ramp-up time histories. Moreover, we compare the time dependence of TPW under assumptions consistent with the canonical equilibrium stability theory adopted in most previous analyses of convection-induced TPW, and a stability theory that includes two effects that have not been considered in previous geophysical analyses: (1) the so-called 'remnant rotational bulge' associated with the imperfect reorientation of the rotational bulge due to the presence of an elastic lithosphere; and (2) a stable (over the timescale of the forcing) excess ellipticity. As a first application of the new theory, we consider recent inferences of rapid (order 1 Myr) TPW motion of amplitude 10°-20° during the Late Cretaceous. We conclude that excursions of this amplitude and timescale are physically implausible.

Original languageEnglish (US)
Pages (from-to)1319-1333
Number of pages15
JournalGeophysical Journal International
Volume187
Issue number3
DOIs
StatePublished - Dec 2011
Externally publishedYes

Fingerprint

inference
Earth (planet)
Cretaceous
lithosphere
time dependence
Ice
ellipticity
predictions
ramps
retraining
Earth mantle
ice
convection
histories
timescale
prediction
Pleistocene
mantle
history

Keywords

  • Earth rotation variations
  • Palaeomagnetic secular variation
  • Rheology: crust and lithosphere

ASJC Scopus subject areas

  • Geochemistry and Petrology
  • Geophysics

Cite this

The rotational stability of a convecting earth : Assessing inferences of rapid TPW in the late cretaceous. / Chan, N. H.; Mitrovica, J. X.; Matsuyama, Isamu M; Creveling, J. R.; Stanley, S.

In: Geophysical Journal International, Vol. 187, No. 3, 12.2011, p. 1319-1333.

Research output: Contribution to journalArticle

Chan, N. H. ; Mitrovica, J. X. ; Matsuyama, Isamu M ; Creveling, J. R. ; Stanley, S. / The rotational stability of a convecting earth : Assessing inferences of rapid TPW in the late cretaceous. In: Geophysical Journal International. 2011 ; Vol. 187, No. 3. pp. 1319-1333.
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