SOLUTIONAL CAVE GENESIS: THE DEVELOPMENT OF IDEAS, 1880-1960

Modern approaches to karst landforms and the dissolutional cave systems that drain them arose in the mid- to late 19^th Century, with a strong focus on the mountainous Dalmatian karst lands where the studies of J. Cvijic (Das Karstphänomen 1893) were foundational. Cvijic emphasized the speleogenetic importance of a seasonally flooded (‘epiphreatic’) zone above the low stage water table. Other Europeans argued for principal development throughout the vadose zone, however, because abrasion by clastic load there might greatly enhance cave conduit enlargement by the supposedly weaker process of carbonate dissolution. In 1930 the leading geomorphologist of the time, W.M. Davis, proposed a flatly contradictory model of preferential cave development at random depth in the phreatic zone, which was reinforced in 1942 by the noted geologist, J. Harlen Bretz, based on his studies in Missouri caves. Hydrologist A.C.Swinnerton (1932) countered with a probabilistic argument for cavernous development along the water table, the conduits propagating progressively downstream from the head. In 1941 R.Rhoades and N.M. Sinacori advanced an elegant model for recessional conduit enlargement from the outlet spring headward into the karst massif instead, creating a water table cave. In the 1950s many authors described empirical evidences seeming to favor one or another of these competing possibilities for unconfined meteoric water circulation creating systems of caves. Hypogene cases (interformational meteoric or thermal waters rising from below to create solutional caves) were neglected. In 1958 an influential study of the kinetics of calcite dissolution by P.K. Weyl placed sharp limits on solvent penetrability into limestone fractures or matrix: this appeared to swing the pendulum back in favor of the early vadose concepts, setting the stage for the intensive studies of solution chemistry, kinetics and cave development that there have been during the last fifty years.