CAVE

1- What is a cave?

ANSWER - A cave is a natural cavity formed in a rock, and this cavity must be of a size that allows the entrance of human beings to seek shelter or for study purposes.

2- What are the most common forms of a cave?

ANSWER - In general, the cave has a form of a tube that enters the rock with a slope of about 45º, that is, the cave extends in length and down the rock. But, the caves were formed by several processes and that act on rocks of many types of origin and in the most diversified environments, with that their forms can have the most varied aspects.

3- What are the main processes of formation of the caves?

ANSWER: The caves originate from a series of geological processes that may involve a combination of chemical, tectonic, biological and atmospheric transformations.

        The main ones are: volcanic; coraline; karst; glacier.

4- How is a volcanic cave formed? Give example!

ANSWER - In regions of the globe where volcanic activity is active, lava flow can form several caves, as the lava flow cools and solidifies it can form so-called lava tubes for miles.

     The best-known examples of volcanic formation caves are in Kenya and Hawaii. In Hawaii, the 65,000-meter-long (40.7 miles) Kazumura cave is known to deepen up to 1.1 meters (3.61 feet), forming the longest and deepest lava tube known.

Photo above - volcanic cave at Valentine Cave in California, United States of America.

5- How is a coral cave formed?

ANSWER - During the formations of coral reefs, in the sea, cavities are created, in galleries and halls that can be entered into the reefs by divers.

6- How to form a glacial cave?

ANSWER - A glacial cave is not formed on a rock, but on the ice of the glaciers. Its formation is through the process of passing water from the top of the glacier to the rocky bed, or it originates tubes both horizontally and vertically. This special type of cave has a short life, because it can change its configuration quickly, but it is often visited for the study of glaciers and paleoclimatology research.

Photo (2012 year) - Photographer Skarpi Tharainsson inside cave glacier in Iceland. Photographing the interior of a glacial cave is a very risky adventure, as they are fragile and extremely unstable structures. 

7- How to form a karst cave?

ANSWER - The waters of rivers and rains are caves forming agents in the karstic or chemical process. It is noted that it is not all the rocks that decompose under the action of the waters.

    The karstic caves occur in regions of carbonate rocks (limestone, marble and dolomites), mainly as well as gypsites and evaporites.

     The process of karsification or chemical dissolution is the result of the combination of rainwater or surface rivers with carbon dioxide (CO2) from the atmosphere or from the roots of vegetation. The result is a solution of carbonic acid (H2CO3), or acidic water, which corrodes and dissolves the minerals of the rocks.

Photo above: karst formation cave of New Zealand (Maori Leap Cave, Kaikoura).

8- What are speleothems?

ANSWER: The flow of water inside a cave over thousands of millions of years, dripping from ceiling to floor, forms the speleothems that are elongated forms from the agglutination of minerals dissolved in water.

     The best known speleothems are stalactites and stalagmites.

9- What are stalactites?

ANSWER - Stalactites are the conical forms hanging from the roof of a karstic cave.

Photo above - Stalactites that form from the roof of a cave. Note that in addition to the speleothems of the stalactite type, other speleothems such as the columns are clear in the picture.

10 - What are stalagmites?

ANSWER: Stalagmites are a particular type of speleothem on the floor of a karst cave, in the form of cones. Dripping over thousands of millions of years from the stalactites causes the agglutination of dissolved minerals (bicarbonate of calcium) on the floor of the cave to form the stalagmites, as if they were the image in the mirror of the stalactites.

Photo above - showing the stalagmites on the ground, as opposed to the stalactites on the roof of the cave.

11 - Any hole, or cavity, in the rock with large dimensions as possible for anyone to enter it is a cave, under the definition of caving?

ANSWER - The answer is no!

     Caving - which, according to the French speleologist Bernard Gèze, means: "the discipline devoted to the study of caves, their genesis and evolution, the physical environment they represent, their current or past biological settlement, and the means or techniques that are proper to his study "- considers a cave only the one formed by natural process.

      For example, in the Brazilian city of São Gonçalo, state of Rio de Janeiro, there are interesting formations of artificial caves, called Caulim Caves, as a result of the withdrawal of kaolin ore (white clay).

Geografia Newton Almeida http://geografianewtonalmeida.blogspot.com.br