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Cave formationsCave formationsBy Ben and KieranBy Ben and Kieran
FormationFormation
Caves are formed by geologic processes. These may involve a combination of chemical processes, erosion from water, tectonic forces, micro-organisms, pressure, and atmospheric influences. Most caves are formed in limestone by dissolution.
Formation cont.Formation cont. Some caves are formed at the same time as Some caves are formed at the same time as
the surrounding rock. These are sometimes the surrounding rock. These are sometimes called called primary cavesprimary caves. .
Sea cavesSea caves are found along coasts around the are found along coasts around the world. A special case is world. A special case is littoral caveslittoral caves, which , which are formed by wave action in zones of are formed by wave action in zones of weakness in sea cliffs. Often these weakness in sea cliffs. Often these weaknesses are faults, but they may also be weaknesses are faults, but they may also be dykes or bedding-plane contacts. Some wave-dykes or bedding-plane contacts. Some wave-cut caves are now above sea level because of cut caves are now above sea level because of later uplift. later uplift.
Formation cont.Formation cont. Ice cavesIce caves Glacier cavesGlacier caves occur in ice and under occur in ice and under
glaciers, formed by melting. They glaciers, formed by melting. They are also influenced by the very slow are also influenced by the very slow flow of the ice, flow of the ice,
Fracture cavesFracture caves are formed when are formed when layers of more soluble minerals layers of more soluble minerals (soluble rock)(soluble rock)
Formation orderFormation order
Phreatic cave passages (or phreatic tubes) are formed below the water table by water flowing under pressure. They can vary in size from a few centimetres to several metres in diameter.
Formation orderFormation order
A stream flowing along the bottom of a phreatic tube
The stream gradually begins to carve a trough in the bottom of the
tube. This is called the vadose stage of development
Formation orderFormation orderA Keyhole PassageEventually a "key-hole" shaped passage may be formed with the stream flowing at the bottom of a deep rift. Progress along these passages may be made by walking along the bottom of the rift. However, the rift may be so narrow that cavers will need to traverse along the tube at the top.
Formation orderFormation order
A Breakdown ChamberEventually the water may form enormous caverns and a period of breakdown, where large boulders crash down from the cave roof, begins.Ancient waterways may become completely abandoned and are called fossil passages
Cave formation picsCave formation pics
Cave formation pics cont.Cave formation pics cont.