November 11, 2009
Cave Report
Caves
Sea caves are formed at the coastal line where the water, whether it be sea, ocean, or lake, meet the weakness of the rock like faults, different sediments, or weaker layers. They are formed by the power of the ocean, in some cases lakes, attacking zones of weaknesses in coastal cliffs. The cave may begin as a very narrow crack into which waves can penetrate and exert tremendous force, cracking the rock from within by both the weight of the water and by compression of air. Sand and rock carried by waves produce additional erosive power on the cave's walls. Painted Cave on California's Santa Cruz Island and Riko Riko Cave, on the Poor Knight Islands off the east coast of New Zealand's North Island are two examples of sea caves.
Lave tube caves are form near volcanoes. During long lasting eruptions, lava flows in streams and if there is too much lava in the stream, it starts to build up on the walls and top. When the lava stops coming out of the Earth, the melted lava in the tube flows downhill leaving a lava tube cave. Lava tubes are formed when an active low-viscosity lava flow develops a continuous and hard crust, which thickens and forms a roof above the still-flowing lava stream. Tubes form in one of two ways: by the crusting over of lava channels, and from pahoehoe flows where the lava is moving under the surface. Caves formed in lava are found where volcanoes have produced certain types of flowing lava and other volcanic hot spots. Kazumura Cave and Huehue Cave, both from Hawaii, are two examples of lava tube caves.
Solution caves are formed by the flow of water through limestone and similar rocks. Water seeps into the pores and cracks of rocks and soil and bubbles beneath the earth above. Sometime later, some of the water reaches an area where all the cracks and pores are already filled with water. The upper area is called the water table. A chemical process occurs when calcite, the main mineral of limestone,...