**Modeling of Calcium Carbonate Precipitation in Natural
Karst Environments under Hydrodynamic and Chemical
Kinetic Control**

**Participants: I.D. Sasowsky (Geology), C. B. Clemons (Theo and Applied
Math), G. W. Young (Theo and
Applied Math), E.
Wright (Mathematics, Univ of Montana-Western)**

This work addresses some of the fundamental unanswered
questions concerning the physics and chemistry of rimstone
formation. Rimstone (travertine) dams and flowstone
formations are mineral deposits that are found on the land surface, in caves,
and in other settings. These formations appear to
evolve under geochemical and hydrodynamic control. Mathematical modeling of
this solid-aqueous system is carried out, in order to explain the system scale
(cm-meter) patterns of rimstone dams in these
deposits. The mathematical model consists of a system of equations to describe
the combined behavior of a thin fluid film, reactive chemical species, and
moving interfaces (air-fluid and fluid-mineral). Comparison of field study
measurements and geochemical analyses (pH and ion concentrations) in the
literature with model predictions are used to identify the relationships
between the spatial features of the dams and their surroundings, such as the
slope of the underlying substrate. Furthermore, this modeling
investigation extends previous models through formulation and solution
strategies to determine the locations and spatial features of the
fluid-atmosphere and fluid-mineral surfaces, and more generally quantifies free
surfaces in precipitative pattern formations.

__Publications:__

- Modeling
of Calcium Carbonate Precipitation in Natural Karst
Environments Under Hydrodynamic and Chemical
Kinetic Control, B. Justice, C. B. Clemons, I. D. Sasowsky,
G. W. Young, and E. Wright,
*In preparation*.