Dive into cave weathering and erosion! Caves are hollow spaces underneath the earth’s surface with openings large enough for a person to enter. Many caves form in a karst environment, a type of landscape made of rocks like limestone, or dolomite, that slowly dissolve in the presence of water with a slightly acidic tinge. There are several different types of caves, and they are named by how they are formed. The most common type of cave is a solutional cave, a cave formed by the chemical reaction of water with limestone bedrock. While chemical weathering gets things started, caves continue to develop over time through ongoing physical and chemical weathering, as well as erosion.