Travertine terracing: patterns and mechanisms - Tufas and Speleothems: Unravelling the Microbial and Physical Controls - page 348

tension affects the hydrodynamics especially at
smaller scales, influencing terrace morphology.
In spite of recent results, travertine terracing
remains an intriguing problem. Although there are
many candidate mechanisms, the precise nature of
precipitation localization under different conditions
is not known. Do terrace size and spacing stabilize
under certain conditions, or do they always continu-
ously coarsen? When do we see terrace size distri-
bution following a random null model (Veysey &
Goldenfeld 2008) and when do we see a character-
istic wavelength (Ogawa & Furukawa 2002)?
What effects do parameters such as flux, oversatura-
tion and slope have on patterning, and why? Such
questions can probably be answered through a com-
bination of computer simulations, theoretical
studies, field studies and laboratory experiments,
but the complexity and diversity of the system
should not be underestimated. As noted by Veysey
& Goldenfeld (2008), travertine precipitation is a
convenient geological process to study because of
the relatively fast processes. In addition, the acces-
sibility of this earth-surface system, the availability
of analytical and computational techniques, the
cross-disciplinary nature of the problem and the
sheer beauty and mystique of travertine terraces
all

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make travertine terracing an attractive area

of research.

We would like to thank Paul Meakin for valuable discus-
sions, and Allan Pentecost for permission to use his data
for figure 5. This study was supported by a Center of Excel-
lence grant to PGP from the Norwegian Research Council.

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