Caves, formation

Bischoff JL, Fitzpatrick JA (1991) U-series dating of impure carbonates An isochron technique using total-sample dissolution. Geochim Cosmochim Acta 55 543-554 Broecker WS, Olson EA, Orr PC (1960) Radiocarbon measurements and annual rings in cave formations. Nature 185 93-94... 

Acids and bases are found throughout nature. In fact, acids and bases are used as a defense mechanism by insects and can produce beautiful limestone cave formations. If not monitored carefully, however, acids and bases in the environment can cause a lot of harm. 

Figure 7.1 Cave formations are caused when rainwater and carbon dioxide mix and form a weak carbonic acid, which then dissolves the calcium carbonate of limestone beneath the earth, allowing for cave formation. The photo shows stalactites and stalagmites and other formations at Luray Caverns in Virginia.

Stalagmites are cave formations that start on the floor and grow upward. These formations are caused when water that contains dissolved limestone drips from the ceiling of the cave and lands on the same spot. Sometimes, water dripping off of a stalactite will actually form a stalagmite directly below it. Eventually, a column forms when the stalactite and stalagmite meet. This feature can take thousands or even millions of years to form. 

Jol, Harry. Cave formations, University of Wisconsin—Eau Claire Web site. Available online. URL http //www.uwec.edu/jolhm/ Cave/caveform2.htm. Accessed on March 19, 2008. 

Stalactite An icicle shaped cave formation that hangs from the ceiling. 

Stalagmite A cone-shaped cave formation that is formed on the cave floor when water containing dissolved calcium carbonate drips from a cave s ceiling. 

Solution caverns or caves often contain deposits of recrystallized calcium carbonate, usually in the form of the mineral aragonite. Stalactites, stalagmites, and other cave formations are called speleothems. Created gradually by the precipitation of aragonite from groundwater, many speleothems display a layered structure. Recent study shows that bacteria and other simple life forms may contribute to the formation of cave deposits. 

Weather Balloons Cave Formation Bacterial Refining of Ores... 

Applying Identify two physical changes and two chemical changes that occur in cave formation. 

Write the equations for cave formation from the MgC03 part of dolomite, CaC03 MgC03. 

When the solution reaches a cave, carbon dioxide slowly escapes from the solution, and the subsequent shift in the equilibrium causes CaC03 to be precipitated. Deposits of CaC03 produce the attractive cave formations. 

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