A. Klimchouk, F. Cucchi, J. M. Calaforra, S. Aksem, F. Finocchiaro, P. Forti.
// Int. J. Speleol. 25 (3-4), 1996. – P. 37-48/Field measurement of gypsum dissolution rates
Dissolution of gypsum in different environments
Additional discussion and conclusionsStudies of dissolutional denudation rates in limestone karsts are relatively numerous. Although there is a relatively long history of such studies, there are still many methodological problems involved, as is illustrated by the review provided by Ford & Williams (1989). Such problems are not specific to limestone karsts; they are also relevant in the context of the estimation of gypsum dissolution rates, but to an even greater extent because of the higher dynamics, and hence the higher spatial and time-related irregularity, of gypsum dissolution. Furthermore, examples of regional estimates and field measurements of gypsum dissolution rates are relatively scarce.
Calculation of dissolutional denudation rates on the basis of solute load involves continuous monitoring of discharge and concentration parameters, and determination of value limits for the particular basin. All these characteristics are commonly obtained using a variety of methodologies, experimental designs and field installations, so that results from different regions are barely compatible. Furthermore, dissolutional denudation rate values derived from such studies give no, or few, data relating to the spatial distribution of the process throughout the 3-D karst system. The potentially great variety of dissolution rates between different environments (conditions of water-rock interaction) within a karst system cannot be revealed by studies of this sort.
Regional estimates of dissolution denudation rate values from solute load studies have been made for various gypsum karsts in the former Soviet Union and elsewhere, but they cannot safely be compared, due to differences of methodology and variable data quality. More detailed discussion of them provides little of relevance to the understanding of either the dissolution process itself or the evolution of karst forms.
The usefulness of dissolution rate values derived on the basis of weight or volume loss of samples, or by direct micro-erosional measurements, is limited mainly because their extrapolation through space is problematical. However, they do provide information that is valuable to the interpretation of dissolutional processes in particular environments, and in relation to karst form evolution. Such studies are more effective for gypsum than for limestone karsts because of the much higher characteristic dissolution rates, which make the errors involved in measurement relatively insignificant and allow the dissolution dynamics to be monitored, even over comparatively short timescales
