Final answer:
Cave sites are formed through the reaction of carbonic acid with limestone, resulting in the dissolution and forming of cavities underground. Over thousands of years, the process creates large caves and the precipitation of minerals from water forms stalactites and stalagmites. Cave art provides insight into the lives and expressions of prehistoric humans.
Step-by-step explanation:
The basic steps of how a cave site is formed begin with the dissolving action of carbonic acid on limestone. When glacier water or rain mixes with carbon dioxide, it forms a weak acid that slowly erodes the limestone. Over time, this water erodes the rock, creating the large areas within caves. Due to the instability of rocks, cave entrances may be blocked by erosion and rock slides, which helps preserve the caves over millennia.
Limestone, which forms the basis for most caves, consists mainly of CaCO3 and originates from marine life skeletons. When groundwater containing atmospheric CO2 seeps into the limestone, it causes the limestone to dissolve, a process that can take tens of thousands of years. As this acidic water continues to move through the limestone, it enlarges microscopic cracks until a cave is formed. Further dissolution and deposition of calcium carbonate lead to the formation of stalactites and stalagmites, adding to the cave's unique features.
Cave art, found on the walls of some caves, provides a unique insight into the lives of prehistoric humans. These drawings, which may have had religious or narrative purposes, were made using minerals like charcoal and ochre. The creation of art in such a challenging environment suggests that these ancient humans dedicated time and effort to artistic expression despite the harsh realities of their existence.