Tour Day 19: Wednesday, May 9, 2001
Li River Cruise
These strange knobby hills are what makes the Li River so famous.
Karst is a geologic term that describes geologic formations subject to forming caves and sink-holes. Limestone and gypsum are typical materials that makeup these kinds of formations. They dissolve easily in water. Over time the ground water will migrate in an underground stream carrying the dissolved material along with it. Eventually caves will form, then sink-holes if the cave ceilings give away.
From Underground Stream
This is an enlarged view of the cliff in the picture below.
Continued from above.
Take this idea to the extreme and you will find that these knobby hills are what is left after so much of the rock has dissolved and been carried away. As we move down river, you will see several waterfalls in these pictures such as the one at left. These underground streams continue to gnaw away at the inside of these hills. Eventually, of course, these hills will be completely eroded away, and the area will be a plain. We won't be around to observe it, however.
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Page last updated June 22, 2001.