Cavern and Mineral Deposits:How Caverns Form

Limestone dissolves more easily than other types of rock

Limestone is dissolved by groundwater because it always contains some carbonic acid.

Dissolving the calcite in limestone creates/increases porosity

Limestone formations are also split by fissures

After 1000's of years, cracks become so large that they form networks of underground tunnels

These tunnels are caverns, or caves

Sinkholes form when parts of a cave roof collapses. Ponds or lakes form when the sinkhole meets the water table

Karst Topography In regions of caverns, most

rainwater enters the ground through sinkholes and fissures, and there are very few surface rivers

Regions characterized by sinks, sinkhole ponds, lost rivers, and underground drainage are said to have Karst Topography

The bedrock is calcite, dolomite, or other minerals that dissolve easily

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Mineral Deposits by Groundwater Minerals dissolved in groundwater are deposited in a variety of

ways When water drips from the roof of a limestone cave is deposits

calcite as stalactites On the floor beneath the stalactites, blunt, round masses called

stalagmites are formed. Columns or pillars form when they meet These are examples of dripstones, and only form when water can

evaporate above the water table.

Calcite deposits around mineral springs are called travertine Hot water pours out of long hillside fissures, depositing some calcite

as it cools. Geyserite forms around the opening of geysers, it is silica dissolved

from the hot igneous rock through which the geyser water pass. Petrified wood is formed when minerals dissolved in groundwater

replace the decaying wood of buried trees The most important groundwater deposit is the cement that binds

together sand grains and pebbles of sedimentary rocks.