Publication Date

12-1993

Advisor(s) - Committee Chair

Christy Grove

Degree Program

Department of Geography and Geology

Degree Type

Master of Science

Abstract

The laboratory-derived calcite dissolution rate law of Plummer et al. (1978) is the most widely used and mechanistically detailed expression currently available for predicting dissolution rates as a function of water chemistry. Such rate expressions are of great use in understanding timescales associated with limestone karst development. Little work has gone into the field testing of the rate law under natural conditions.

This work compared measured dissolution rates measured by a crystal weight loss experiment in Buffalo Creek within Fort’s Funnel Cave, which lies within a pristine, forested catchment of Mammoth Cave National Park. Continuous water chemistry sampling over the same period allowed a time-integrated prediction of the dissolution based on the Plummer et al (1978) expression. Results indicate that the rate law overpredicted dissolution by a factor of about ten. This concurs with earlier laboratory work suggesting that the law tends to overpredict rates in solutions close to equilibrium with respect to calcite, as were the waters in this study.

Estimating dissolution rates with the expression under varying hydrologic conditions also allowed a prediction of storm scales change in cave forming processes. Neglecting effects of sediment masking on the bed, it was found that 78% of the work done in the dissolution of the cave passage during the study period occurred at or around baseflow conditions, with only a small amount during the effective but infrequent high flow conditions.

Disciplines

Earth Sciences | Geochemistry | Geology | Hydrology

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