Ma. Pais et al., Late Precambrian paradoxical glaciation and obliquity of the Earth - a discussion of dynamical constraints, EARTH PLAN, 174(1-2), 1999, pp. 155-171
G.E, Williams' observations on Late Precambrian glaciogenic sequences pose
some major challenges to the understanding of the dynamical evolution of th
e Earth's orbit and spin that have not yet been adequately addressed. In th
is paper, we investigate whether dissipative core-mantle coupling is an eff
ective mechanism for reducing the obliquity by such a large amount as sugge
sted by Williams [G.E. Williams, Earth Sci, Rev. 112 (1993) 1-45], and we e
xamine the relationship between the obliquity and spin rate in the presence
of such coupling. We show that this mechanism not only cannot explain the
rapid and substantial decrease in obliquity, but also that such a decrease
is in contradiction with existing paleorotation evidence for the same perio
d, thus confirming the previous findings of Ni ron de Surgy and Laskar [O.
Neron de Surgy, J. Laskar, Astron. Astrophys. 318 (1997) 975-989]. (C) 1999
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