Name: Pat B.
Status: Student
Age: 13
Location: N/A
Country: N/A
Date: February 18, 2004
Question:
How does water create caves?
Replies:
Most caves are formed by groundwater charged with CO2 (carbon dioxide) which forms carbonic
acid that dissolves limestone (calcite) beneath the surface of the earth. This takes a while
to happen. Some caves are formed from erosion caused by water moving through cracks in bedrock
and widening the cracks.
Caverns form at or below water table in zone of saturation where water in the ground dissolves
the rock leaving empty space which we call caves or caverns. Dripstones form after water table
drops from dripping of water loaded with dissolved minerals.
Stalactites hang from the roof of the cave.
Stalagmites form on the floor of the cave.
Columns and pillars form when stalactites and stalagmites grow together.
Steve Miller
If the rocks are right (often jointed and fractured limestone) and there is sufficient
moisture/rainfall, caves may form in some areas. As acidic rain soaks into the ground it
can react with limestone to dissolve it. The weakest parts of limestone are the places with
joints and fractures, and these areas dissolve, creating voids and pathways for water. As
water continues to enter the pathways, they enlarge with further dissolving until caves form.
You can probably find some pictures or diagrams of this in a geology book or on-line.
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