Cave rainwater and groundwater charged with HCO (carbonic acid) and naturally occurring organic acids. The dissolution process produces a distinctive landform known as "karst", characterized by sinkholes and underground drainage. Limestone caves are often adorned with calcium carbonate formations produced through slow precipitation. These include flowstones, stalactites, stalagmites, helictites, soda straws and columns. These secondary mineral deposits in caves are called "speleothems". The portions of a solutional cave that are below the water table or the local level of the groundwater will be flooded. Lechuguilla Cave in New Mexico and nearby Carlsbad Cavern are now believed to be examples of another
Blombos Cave terrain abruptly drops down towards shoreline that lies some 34,5 meters below the cave entrance. The talus, which primarily consists of Middle Stone Age deposit, rock fall and unconsolidated sediments, is stabilised by an area of large, exposed blocks (14m²). At some stage - and in between the prehistoric occupation of the cave site - these blocks have fallen down from the rock face above, effectively preventing site erosion and allowing sediments to stabilize and accumulate in front of the cave's drip line. Calcium carbonate (CaCO3) rich ground water seeps in from the cave roof and percolates through the interior