Geology Reference
In-Depth Information
Eventually, the stalactites and stalagmites grow together, meeting in the middle and
forming a column.
One way to recall the difference between a stalactite and stalagmite is to re-
member that stalactites hang “tite” and you “mite” trip over a stalagmite.
Sinkholes and disappearing streams
In karst landscapes, the abundance of caves below the surface may cause a sinkhole. A
sinkhole is created when the rock below the soil is dissolved by groundwater and the
soil sinks to fill the space, creating a depression. Sinkholes may also result from the roof
of a cave collapsing, leaving a depression in the ground surface.
When you see a sinkhole, you can be certain the underlying rocks are soluble.
In the United States, sinkholes are common in Florida, Georgia, North Carolina,
and South Carolina. They can also be found in many different regions of the world.
The presence of sinkholes causes disappearing streams. Disappearing streams flow
across the surface for only a short distance before they encounter a sinkhole. The sink-
hole has changed the slope of the ground surface by sinking downward. The stream
flows down into the sinkhole and “disappears” below ground, continuing to flow, but go-
ing through caves and underground spaces left in the soluble rock by previous ground-
water.
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