Caves are beautiful and mysterious sights, hidden deep below the Earth. Going down into one from above and suddenly coming into a room with colorful rock seeming to drip from above. It is awe-inspiring to imagine how these wonderful creations came into being.
Arkansas is lucky enough to have several wonderful caves within its borders. Several are privately-owned, some are extremely dangerous. One however, is operated by the U.S. Forestry Service. It is Blanchard Springs Caverns. Located near Mountain View, these caves are open to the public for tours.
This web page will focus on Blanchard Springs Caverns, however, most of the facts will apply to other Arkansas caves.
Life In Caves
Plants and animals in caves, like those above ground, have adapted to their surroundings. The caves have recognizable zones, within each you will find various communities of plants and animals. The entrance zone is most like the outside surface area. Some shade loving plants grow in the twilight zone but extend only to the deepest point where light penetrates. Temperature in the variable zone fluctuates with the weather outside. Deeeper in the caverns you have a constant temperature zone, the temperature remains at 58 degrees, regardless of the outside weather.
Biologist recognize three kinds of cave animals. Those that live above ground, but come below for various reasons, cave guests. These include bats and crickets, trogloxenes. A favorite trogloxene in Blanchard Springs Caverns is the gray bat. Next you have animals that live mostly in the caves but have the ability to live outside, some salamanders, and frogs are troglophiles or cave lovers. Last, you have animals that spend their entire lives in the caverns' total darkness these are called troglobites, or cave dwellers. These include the white Ozark blind salamander, many are sightless and without pigment.
The mosses and ferns of the entrance zone give way to very little plant life, except for some mold and fungi. Bacteria in the debris dropped into the caves by water sustain some forms of life. Microscopic organisms are food for larger aquatic cavern animals such as isopods, flatworms and amphipods. They are eaten by larger animals such as salamanders and crawfish.
The name used to describe any kind of cave formation is speleothems. The main mineral deposited in the speleothems of Blanchard Springs Caverns is calcite. This is the same mineral found in the limestone layers that make up the bedrock of the Ozark Plateau.
Calcite is dissolved from the limestone when surface water, containing carbonic acid absorbed from the air and soil comes down from the rock above down into the caverns. When this acidic water carrying a calcium bicarbonate solution encounters the air in the Caves, the carbon dioxide is released. The water then deposits the calcite. Layer upon layer of calcite deposit will eventually shape the speleothem.
Many things determine the shape that the deposits take. How the water enters the cave, either by dripping, flowing, seeping, or splashing helps determine the shape. Along with this is how it flows or stands after entering.
Sometimes the calcite speleothems have pastel and earth colors. This indicates that other minerals were deposited, continuously or at intervals. Iron oxides account for the shades of brown, yellow, and red, while manganese gives shades of blue, black and gray.
These formations have many different names depending on how they were formed they include:
SODA STRAWS: (first stage stalactites) grow from the ceiling as water runs down inside them and deposits rings of calcite at their tips.
STALAGMITES: These rise from the floor when dripping water deposits mineral, they are usually larger in diameter than stalactites and more rounded on top.
FLOWSTONE: Forms when considerable water flows or runs down walls, over floors and older formations, building up sheets of calcite like frosting on a cake.
STALACTITES: When the soda straws are plugged, water trickling down their outsides turns them into these larger carrot shaped deposits.
CAVE BACON: At times, water forming draperies contains minerals in addition to calcite, resulting in dark orange or brown bands.
DRAPERIES OR CURTAINS: On an inclined ceiling, water may deposit calcite in thin translucent sheets.
Blanchard Springs Caverns, U.S. Forestry Service; 2000, The Creative Company