Arbel, Y., Greenbaum, N., Lange, J., Shtober-Zisu, N., Grodek, T., Wittenberg, L., and Inbar, M. 2008. Hydrologic classification of cave drips in a Mediterranean climate, based on hydrograph separation and flow mechanisms. Isr. J. Earth Sci. 57: 291-310.Processes of infiltration to groundwater in a karstic area were studied by monitoring and sampling cave drips during 2004-2008 at two sites with different lithologies: dolomite of the Yagur Fm. and crystalline limestone of the Muhraqa Fm., in Mt. Carmel, Israel. Two tracer tests under different antecedent moisture conditions and "rainfall" intensities were performed.At both sites, 4 hydrological drip types were identified: Post-storm, Seasonal, Perennial, and Overflow, each exhibiting different patterns of discharge, chemistry, and travel time. Perennial drips represent the slow ("matrix") component; however, discharge and [Cl -] fluctuations after intense rainstorms indicate the relative contribution of by-pass flows (event-water). Based on [Cl -] during the natural season and electrical conductivity (EC) during the sprinkling experiment, seasonal and storm input of event-water versus old-water were calculated in the various drips using hydrograph separation. The fractions of calculated event-water in the perennial drips were always <30%. Overflow drips started late in the season, after drainage in the nearby drips exceeded their discharge capacity.Hydrograph recessions of drips have exponential drainage of few "reservoirs". Perennial and seasonal drips had at least two recession segments: (1) recession of quick-flow governed by a piston flow effect and small input of preferential flow, which lasted up to 10 days; (2) slow drainage of the vadose zone, which continued for a few months or until the next season. The recession constant(s) for post-storm and overflow drips were shorter than 10 days."Piston flow" effect indicators were the lag time of injected tracers after hydrographs onset, and the larger component of old-water in drips-hydrograph onset and rising limb. The different processes, associated lag times, and flow velocities have major impacts on groundwater vulnerability and aquifer recharge.

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[1] Fluid microinclusions in stalagmites have provided samples of paleowaters present during the growth of the stalagmite, but only in microliter amounts. Genty et al. (2002) discovered much larger water-filled macroinclusions in some stalagmites. Using computerized tomographic (CT) X-ray-scanning and magnetic resonance imaging (MRI) we searched for such macroinclusions in 21 stalagmites from diverse localities in North and Central America and the Caribbean. We show that most stalagmites contained numerous mm to cm-sized internal cavities (macroholes). These do not penetrate the outer surfaces which in most cases are deceptively unblemished. Some stalagmites have up to 10% average internal porosity. Two types of macroholes are distinguishable: axial holes formed during growth due to slower calcite accumulation at the axial drip site; off-axis holes formed penecontemporaneously with growth in discrete layers; these cut previous growth laminae showing that they are post-depositional. Using MRI on uncut, apparently sealed specimens, we find that very few of these cavities contain significant quantities of water although they were clearly formed while the stalagmite was being continuously bathed by drip water. Presumably, the water has escaped post-depositionally, through micro fissures, extensive connected hole system, crystal boundaries or other defects.

Massive destruction of carbonate rocks occurred on the slopes of Mount Carmel during the severe wildfire in 2010. The bedrock surfaces exhibited extensive exfoliation into flakes and spalls covering up to 80–100% of the exposed rocks; detached boulders were totally fractured or disintegrated. The fire affected six carbonate units – various types of chalk, limestone and dolomite. The burned flakes show a consistent tendency towards flatness, in all lithologies. The extent of the physical disruption depends on rock composition: the most severe response was found in the chalk formations covered by calcrete (Nari crusts). These rocks reacted by extreme exfoliation, at an average depth of 7.7 to 9.6 cm and a maximum depth of 20 cm. Scorched and blackened faces under the upper layer of spalls provide strong evidence that chalk breakdown took place at an early stage of the fire. It is possible to explain the extreme response of the chalks by the laminar structure of the Nari, which served as planes of weakness for the rock destruction. Three years after the fire, the rocks continue to exfoliate and break down internally. As the harder surface of the Nari deteriorates, the more brittle underlying chalk is exposed to erosion.