A ~60 Myr periodicity is common to marine-87Sr/86Sr, fossil
  biodiversity, and large-scale sedimentation: what does the periodicity
  reflect?
  We find that the marine 87Sr/86Sr record shows a significant periodicity of
59.3 \pm 3 Myr. The 87Sr/86Sr record is 171{\deg} \pm 12{\deg}out of phase with
a 62 (\pm 3) Myr periodicity previously reported in the record of marine-animal
diversity. These periodicities are close to 58 (\pm 4) Myr cycles found for the
number of gap-bounded sedimentary carbonate packages of North America We
propose that these periodicities reflect the operation of a periodic "pulse of
the Earth" in large-scale, Earth processes. These may be linked to mantle or
plate-tectonic events, possibly uplift, which affects Earth's climate and
oceans, and so the geochemistry, sedimentation, and biodiversity of the marine
realm. Alternately, they may be linked to oscillation of the solar system
normal to the plane of the galaxy.
