Illinois state Museum

Monroe County, 1673
Cave - Climate and Geology

This cave stays about14 º C. (about 58º F) all year long. Cave temperatures are generally an average of above ground temperatures. The annual precipitation above ground in this area is 87 centimeters (about 34 in.). The precipitation provides sufficient groundwater to keep the cave environment moist.

Caves most commonly form in areas of limestone or dolomite rock. Areas with caves and sinkholes are called Karst landscapes. Most caves in Illinois are less than 3 million years old. In glaciated areas, caves tend to be young. They formed after the last glacier retreated 10,000 years ago. Caves probably existed before the Ice Ages but the enormous weight of advancing ice sheets would have collapsed cave ceilings.

There are more than 300 caves in Illinois. This reconstruction is based on caves in the Ozark Division in the Mississippi River valley.