Cores from the flanks of the Galapagos spreading
centre show that the top 25 cm of pelagic sediments is
highly bioturbated. Kenyon and Turcotte [1985] have
proposed that bioturbation may cause down-slope creep
of the sediment surface and bioturbation may therefore
smooth sediment topography in a similar way to
hillslope creep on land. Assuming this produces
movement consistent with the diffusion transport
model, sediment topography across scarp crests,
digitised from Deep Tow profiler records, is modelled
with a simple analytic solution to the diffusion equation
and with a mean diffusion constant k of ~0.007 m2/yr.
This small value suggests creep rates are modest, for
example, 2 cm/yr for a 30û slope, and is an upper bound
since sediment avalanching and bottom currents
probably also remove sediment from scarp crests.
Although requiring further work, these results suggest
that morphologic dating methods may be applicable to
marine fault scarps and could be useful in relatively
sediment-free areas, such as mid-ocean ridges, where it
is commonly not possible to use datable offset seismic
horizons.
Mitchell, N. C., "Creep in pelagic sediments and potential for morphologic dating
of marine fault scarps", Geophysical Research Letters, 23, 483-486, 1996.