What makes limestone caves

Some of these have been dug out by cavers. The dipping Carboniferous limestones have produced a particular style of cave. A typical Mendip swallet cave is developed where a stream sinks underground at the contact between the Avon Group and the Carboniferous Limestone.

Initially the cave descends steeply, often down dip or along joints, via a series of small cascades or pitches. On reaching the water table the passage enters the phreatic, sub water table zone, marked by a water-filled section known as a sump.

These phreatic passages display a characteristic looping profile as the water flows down a bedding plane, and then ascends up a joint or other fracture to gain higher bedding planes within the limestone en route to the resurgence. As time progresses, the cave will tend towards a more graded even profile.

Erosion at the spring outlet may cause the stream to find a new lower course, leaving the former passage high and dry. In this way a whole series of abandoned former stream courses may lie above the active streamway.

The origin and age of speleothems is a controversial subject. A popular theory for the origin of caves involves two stages. The first stage was when the cavity was filled with water, and solution of limestone occurred.

The second stage was when the cavity or cavern was filled with air, and deposition of speleothems began from solutions depositing calcium carbonate. A less popular theory is that there was only one stage in cave formation with solution occurring in the water-filled part of the chamber concurrently with speleothem deposition in the air-filled spaces. Radiocarbon C dating of speleothems has been used by some scientists to support the great age of cave formations.

However, attempts to date the carbonate minerals directly give deceptively old ages because carbon from limestone with infinite radiocarbon age carbon out of equilibrium with atmospheric carbon has been incorporated in minerals with atmospheric carbon.

Most of the stalactites and stalagmites in modem caves are not growing, and it appears impossible to estimate their former rate of growth. The ones that are growing may be subject to extreme variation in growth rate.

It must be remembered that the rates of deposition of calcite are subject to the same complex environmental factors which affect the rates of solution of calcite see above discussion. Therefore, some of the great ages for speleothems claimed by cave guides and "spelunkers" may be significantly in error.

A large number of reports concern the rapid growth of stalactites and stalagmites. Fisher 18 summarized some of the early literature where stalactite growth averages about 1. Stalagmites observed by Fisher grew 0. At this rate of height increase the 1, centimeter tall stalagmite called "Great Dome" in Carlsbad Caverns might grow in less than 4, years.

A large stalagmite like Great Dome may contain million cubic centimeters of calcite, which, if accumulated in 4, years, would require a deposition rate of 25, cubic centimeters 67, grams of calcite yearly. If the dripping water is assumed to deposit 0. Because about 6, drops comprise 1 liter, it would take about million drops of water per year to form the stalagmite. This works out to 25 drops of water per second; which is a considerable flow.

Whether a stalagmite would be deposited in the above hypothetical situation is not known. One would want to carefully examine the assumptions and the complex environmental factors which might affect stalagmite growth. In addition to the observations of speleothem growth in cave or cave-like natural environments, some interesting experiments have been performed to simulate stalactite and stalagmite growth in control led laboratory situations. Williams and Herdklotz 19 are studying the effects of acidity, salinity, temperature, humidity, and other factors on rates of stalactite growth in the laboratory.

Their work applies to natural cave environments, and indicates that stalactites can form very rapidly. Having examined the processes which can form limestone caves, we are now ready to formulate a model which is consistent with the geologic data and in harmony with a Biblical framework for earth history. Step 1 - Deposition and burial of limestone.

The first step for the formation of a cave is obviously to deposit the limestone. Most major limestone strata appear to have accumulated during the Flood. After a lime sediment layer which later contained a cave was deposited, it would have been buried rapidly under perhaps several thousand feet of sediments.

The weight of overburden would compact the lime sediment and tend to expel interstitial water. Although the fluid pressure would have been great within the sediment, the lack of a direct escape route for the pore water would impede water loss and prevent complete lithification.

The major means of water loss was probably through joints which formed during the early stage of compaction while the sediment was only partially consolidated. Step 2 - Deformation and erosion of limestone and overburden. As the Flood waters receded, tectonic activity would deform the sediments and bevel the upper layers down to a new level. The lime sediment layer would again be near the surface. The tectonic forces would induce movement on joints and build up fluid pressure, and the removal of overburden would make compaction in and flow from partially consolidated sediments proceed at faster rates.

The pressure gradient would have been highest near the surface, causing sediment to be removed by piping. As the joints were opened, a conduit system for vertical and horizontal flow would have been established. Step 3 - Horizontal groundwater drainage and solution of limestone. After the flood waters had completely receded, the regional groundwater level would be in disequilibrium and horizontal flow would be significant.

Acids from organic decomposition at the surface and at depth would tend to move to just below the water table where the highest horizontal velocities of flow would exist. Solution of newly consolidated limestone would occur chiefly in horizontal conduits at a level just below the water table.

The mixing of vadose water CO 2 rich, oxygen rich, organic poor, and low salinity with phreatic water CO 2 poor, oxygen poor, organic rich, and high salinity would also produce conditions ideal for solution of limestone near the water table. As a result, a cave system would be developed at a certain level.

Step 4 - Deposition of speleothems. After the groundwater drainage had been largely accomplished and the caves dissolved out, the water table would be at a lower level and caves would be filled with air, not water. Thus, the final step would be the rapid deposition of stalactites, stalagmites, and flowstone. Caves are among the most fascinating structures in the earth's crust. The processes which removed material from caves in principle are rather simple, but they were manifest geologically in response to many environmental factors.

Deposition in caves was also complex. Although there is much in caves to challenge further study, it appears that they can be interpreted within the basic framework of earth history presented in Scripture. Steven A. In there were over , visitors to the caverns. The caverns are lit but visitors can bring a flashlight when they visit the caves. They dug around at the bottom of the pit and discovered the entrance to the cave. The cave is located within five miles of the Carlsbad Caverns in New Mexico.

Speleothems in Lechuguilla Cave Lechuguilla Cave has many fascinating and unusual speleothems in the cave. The caves contain lemon-yellow sulfur deposits six meters high. Gypsum chandeliers are six meters tall. These deposits led scientists to discover the fact that indicate the cave formed from the bottom up.

The caves formed when water containing sulfuric acid flowing through the limestone created the cave. History and discovery The cave was known for a long time and considered an insignificant cave. The entrance pit to the cave was 27 meter deep. A miner in had a permit and mined bat guano in the only chamber known at the time. Fifth longest cave in the world Lechuguilla Cave is now ranked as the 5th longest cave in the world and the 3rd longest in the United States.

Cavers climbed meters into a dome in and discovering new passages, pits, and large rooms. The known total length of the cave is The cave contains five separate geologic formations that are now being studied inside the cave. Discovering Lascaux caves The Lascaux caves are Paleolithic caves located in southwestern France near the village of Montignac.

The caves were discovered by four boys on September 12, when they were examining a fox hole. The boys constructed a makeshift lamp to light their way and discovered a wide variety of animal paintings on the walls. The next day they again visited the cave with better lighting.

They told their teacher about what they had found. Plans were set in motion to excavate the cave. By the cave was open to the public. Prehistoric cave paintings The caves house some of the most famous examples of prehistoric cave painting ever discovered. There are close to paintings on the interior cave walls and ceilings in the caves. There are also engraving in the cave. Many other caves in the region also have beautiful paintings on their walls.

The cave paintings were painted about 20, years ago. They include horses, deer, aurochs, ibex, and bison.