TeXes Science Practice Test

How are caves like the Indian Echo Caverns primarily formed?

1. Through volcanic activity

2. By the gradual dissolving of limestone

3. Through human excavation

4. By seismic activity

The correct answer is: By the gradual dissolving of limestone

Caves like the Indian Echo Caverns are primarily formed by the gradual process of dissolving limestone, known as chemical weathering. This occurs when acidic water, which can be formed from rainfall that has absorbed carbon dioxide from the atmosphere and soil, seeps into the ground. As this acidic water moves through the soil, it reacts with the calcium carbonate present in limestone, progressively dissolving it. Over time, this process creates voids and caverns within the rock. The formation of caves through this method is a well-documented geological phenomenon, especially in karst terrains where limestone is abundant. The distinctive features of limestone caves, such as stalactites and stalagmites, result from the mineral deposits left behind as the water drips and evaporates. In contrast, volcanic activity, human excavation, and seismic activity do not typically lead to the formation of limestone caves like the Indian Echo Caverns. Volcanic activity tends to create caves through lava tubes, human excavation creates man-made tunnels, and seismic activity might cause fractures in rock but does not dissolve limestone to form caverns.