Caves have always fascinated us as mysterious chambers full of secrets. Indeed, the morphology of caves and the life forms living in such environments are quite different from that of the outside world. All caves are not same but are vastly different depending on the process of formation and location of caves. Caves are usually formed by the erosive action of wind and water on rocky surfaces in a wide variety of landscapes. They are found in deserts, high mountains, within glaciers or in karst landscapes. Caves in karst landscapes are most common and also the most visited ones due to their grand interiors well decorated with stalactites, stalagmites and other speleotherms. The study of caves and cave systems is called speleology. Here is a list of the different types of caves found in our world.
7. Glacier Caves
Glacier caves are caves formed near the snouts of glaciers. These caves usually exist in the form of long tunnels between the underlying bedrock and glacial ice. The caves are formed when the glacier’s surface meltwater drains downwards through crevasses to the base of the glacier. Here, the meltwater supplies the heat to melt the ice at the base, forming tunnels along the length of the glacier as the meltwater moves downwards. Such glacier caves may be several kilometers in length and end at the mouth of the glacier. The glacier caves are usually tubular conduits with intricately sculptured walls, and floors made of bedrock. These caves can only be explored when the surface of the glacier is frozen. At other times, the caves remain full of meltwater. The Kverkfjöll glacier cave in the Vatnajökull glacier in Iceland is an example of a glacier cave.
6. Sea Caves
Sea caves are formed by wave action along coastlines. Such caves are formed when wave action erodes bedrock of sea cliffs over a geological period of time to form caves. Sea caves might be small crevices or large chambers. Sea caves are often a major tourist attraction. Some sea caves can be accessed only by boats during low tide while others are more easily accessible and occur along beaches where it is possible to walk into the caves. Cathedral Cove Sea Cave, in Coromandel, New Zealand is an example of a sea cave.
5. Eolian Caves
Eolian caves are wind-carved caves that usually form in desert areas. Wind carrying silt or sand particles continuously blast against rocky cliffs or similar structures. Over a long period of time, such erosive action of wind creates cave-like structures in the rock which are about a few tens of meters long. White Rocks and Sand Caves found in the Cumberland Gap National Historical Park, Kentucky, US, are examples of eolian caves.
4. Rock Shelters
Rock shelters are produced when the bedrock erosion takes place in insoluble rocks. For example, in places where a resistant rock like sandstone overlies a relatively erosion-susceptible rock like shale, weathering by a stream might wear away the shale leaving behind a rock shelter with a sandstone roof. Although not as complex and intricate as other types of caves, rock shelters are important historical and archeological sites. The Bhimbetka rock shelters, a UNESCO World Heritage Site in Madhya Pradesh, India, is a famous example of a rock shelter.
3. Talus Caves
Talus caves are caves formed between boulders that have naturally fallen into a random heap on the top of a hill or mountain. These caves are usually small in size. The boulders associated with the talus caves are often the cause of landslides and rockfalls due to their unstable nature. The Pinnacles National Park in California, US, is famous for the numerous and accessible talus caves.
2. Primary Cave - Lava Cave
Primary caves are caves that are formed at the same time as the surrounding rock. One of the best examples of such types of caves are lava caves. Lava caves are formed through volcanic activity. When hot liquid lava flows down the slope of a volcano, the surface of the lava cools and solidifies. However, hot liquid lava continues to flow beneath the solidified surface and when the flow stops, a hollow tube remains. Such types of caves are called lava tubes. Lava mold caves, rift caves, inflationary caves, and volcanic conduits are other caves formed by volcanic activity. The Kazumura Cave in Hawaii is an example of a 65.8 km long lava tube.
1. Solution Caves
Solution caves or karst caves are the most common and complex types of cave systems. Solution caves form in soluble rocks, especially limestone. Such caves might also form in marble, dolomite, chalk, salt or gypsum rocks. Solution caves are formed when groundwater seeps underground via cracks, faults, joints, bedding places, and other surface openings. Over geological epochs, small cracks in the rock become large cave systems. Limestone solution caves are very picturesque as they are often adorned with cave formations like stalactites and stalagmites formed by calcium carbonate precipitation. Such caves are formed by the dissolution of limestone by acidic water (water with dissolved carbonic acid).
