![]() ![]() In the case of exceptionally large sinkholes, such as the Minyé sinkhole in Papua New Guinea or Cedar Sink at Mammoth Cave National Park in Kentucky, an underground stream or river may be visible across its bottom flowing from one side to the other. Occasionally a sinkhole may exhibit a visible opening into a cave below. For example, groundwater may dissolve the carbonate cement holding the sandstone particles together and then carry away the lax particles, gradually forming a void. Sinkholes often form through the process of suffosion. The formation of sinkholes involves natural processes of erosion or gradual removal of slightly soluble bedrock (such as limestone) by percolating water, the collapse of a cave roof, or a lowering of the water table. These caves may drain into tributaries of larger rivers. Sinkholes that capture drainage can hold it in large limestone caves. Sinkholes may capture surface drainage from running or standing water, but may also form in high and dry places in specific locations. Formation Sinkholes near the Dead Sea, formed when underground salt is dissolved by freshwater intrusion, due to continuing sea-level drop. Sinkholes may form gradually or suddenly, and are found worldwide. Sinkholes are usually circular and vary in size from tens to hundreds of meters both in diameter and depth, and vary in form from soil-lined bowls to bedrock-edged chasms. Most sinkholes are caused by karst processes – the chemical dissolution of carbonate rocks, collapse or suffosion processes. Sink and stream sink are more general terms for sites that drain surface water, possibly by infiltration into sediment or crumbled rock. A cenote is a type of sinkhole that exposes groundwater underneath. The term is sometimes used to refer to doline, enclosed depressions that are locally also known as vrtače and shakeholes, and to openings where surface water enters into underground passages known as ponor, swallow hole or swallet. For other meanings, see Doline (disambiguation).Ī sinkhole is a depression or hole in the ground caused by some form of collapse of the surface layer. ![]()
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