Why do caves form underground?
Show answer & explanation
Answer: Water dissolves limestone
Earthquakes create cracks — Wrong. Earthquakes create cracks, but caves form primarily from chemical weathering—acidic water dissolving soluble rock like limestone.
Water dissolves limestone ✓ — Correct! Most caves form in limestone through chemical weathering. Rainwater absorbs CO2, becoming slightly acidic (carbonic acid). This acidic water seeps through cracks, slowly dissolving calcium carbonate in limestone. Over millennia, it carves tunnels and chambers. Stalactites and stalagmites form from deposited minerals!
Lava tubes hollow out — Wrong. Lava tubes do create some caves, but the vast majority form from acidic water dissolving limestone over long periods.