Factors controlling exokarst morphology and sediment transport through caves: comparison of carbonate and salt karst
Jirí Bruthans, Ondrej Zeman - (32/1,2003)
In salt karst, very large amounts of sediment load could be permanently trapped underground, due to the high solubility of NaCl. Specific karst forms which have no equivalents in carbonate karst, occur there (huge underground alluvial fans, inlet caves). In a carbonate karst, on the other hand, only small portion of sediment carried by an allochthonous stream could be deposited permanently in the cave, otherwise the cave will become clogged (because of the very low solubility of CaCO3). Three carbonate karst areas with long-lasting development and fundamental differences in endokarst and exokarst forms were studied from many different aspects in the Czech Republic. The authors believe that there is only one primary difference between the Moravian Karst and diffuse recharge karst areas (Czech and Chynov karsts): the frequency and orientation of fissures penetrable by groundwater. All other differences in exokarst and endokarst forms and hydrology are the results of primary difference and its influence on speleogenesis, especially on sediment transport and gradational features. In areas where only bathyphreatic and deep phreatic caves occur, blind valleys and common exokarst morphology never develop, due to the very low velocity of flow in karst conduits, which precludes transport of sediment load.