LN12591 - The stunning variety of patterns shaped by water in karst
caves always awakes admiration and wonder. However, although
geochemistry of calcite deposition is well-known, the reasons of the
astonishing morphological regularity exhibited by the superficial
drape-like undulations remained unexplored so far. The
short-scale wavelets on the surface of stalactites demonstrate that
their scale-invariance is due to a very subtle interplay between fluid
dynamics and geochemistry. The perturbations of the water film flowing
on the stalactite in fact interact with the calcite deposition rate,
thus originating upstream migrating corrugations with a well-selected
wavelength. Stalactite accretion occurs by successive calcite
stratifications shaped by waves remounting the stalactite itself. This
work also shows the wavelength and speed of such waves depend on the hydraulic and chemical characteristics of the cave
environment. Therefore, the geometry of the undulations imprinted in the
stalactite cores retains the record of the local paleoclimate
evolution. These theoretical findings could pave the road to novel
morphological analyses of stalactite specimens, aiming to acquire data
about paleo-flows in karst environments.
