Thin-film-induced morphological instabilities over calcite surfaces

Area of Science:

• Geochemistry
• Fluid Dynamics
• Paleoclimatology

Background:

• Speleothems provide valuable climate records.
• Morphological evolution of calcite precipitation is key to understanding past environments.
• Crenulations are ripple-like instabilities observed in calcite-water interfaces.

Purpose of the Study:

• To investigate the mechanisms driving crenulation formation in calcite precipitation.
• To determine the role of hydrodynamics versus CO2 transport in crenulation patterns.
• To explore the influence of environmental parameters on crenulation instability.

Main Methods:

• Analysis of calcite-water interface instabilities.
• Theoretical modeling of film flow and surface dynamics.
• Investigation of environmental factors like temperature, ion concentration, and slope.

Main Results:

• Crenulation patterns are primarily induced by the hydrodynamic response of the water film's free surface.
• Carbon dioxide transport plays a marginal role in crenulation formation.
• Environmental parameters such as temperature, dissolved ion concentration, and wall slope influence crenulation.

Conclusions:

• Crenulations are a hydrodynamic phenomenon, not primarily driven by CO2 transport.
• Understanding crenulation mechanisms enhances speleothem-based paleoclimate reconstructions.
• Crenulation wavelength may serve as a proxy for past water flow conditions.