__NOTOC__ Dean's Blue Hole is a

blue hole A blue hole is a large marine cavern or sinkhole, which is open to the surface and has developed in a bank or island composed of a carbonate bedrock (limestone or coral reef). Their existence was discovered in the late 20th century by fisherme ...

located in

The Bahamas The Bahamas (), officially the Commonwealth of The Bahamas, is an island country within the Lucayan Archipelago of the West Indies in the Atlantic Ocean, North Atlantic. It takes up 97% of the Lucayan Archipelago's land area and is home to ...

in a bay west of

Clarence Town Clarence Town is a town in the Bahamas. It is located on Long Island. Clarence Town is the capital of Long Island and has a population of 86 people as of 2010.Long Island Long Island is a densely populated island in the southeastern region of the U.S. state of New York (state), New York, part of the New York metropolitan area. With over 8 million people, Long Island is the most populous island in the United Sta ...

and is the world's second deepest, after the

Dragon Hole Dragon Hole, also known as Yongle Blue Hole named after the third Ming emperor, is the deepest known blue hole in the world at deep. It is located about north of Drummond Island in the Paracel Islands. Blue holes generate a distinctive blue co ...

in the

South China Sea The South China Sea is a marginal sea of the Western Pacific Ocean. It is bounded in the north by the shores of South China (hence the name), in the west by the Indochinese Peninsula, in the east by the islands of Taiwan and northwestern Phil ...

, with a depth of .

Formation

is a water-filled

sinkhole A sinkhole is a depression or hole in the ground caused by some form of collapse of the surface layer. The term is sometimes used to refer to doline, enclosed depressions that are locally also known as ''vrtače'' and shakeholes, and to openi ...

with the entrance below the water level. They can be formed in different

karst Karst is a topography formed from the dissolution of soluble rocks such as limestone, dolomite, and gypsum. It is characterized by underground drainage systems with sinkholes and caves. It has also been documented for more weathering-resistant ro ...

processes, for example, by rainwater soaking through fractures of limestone bedrock onto the watertable. Sea level here has changed: for example, during the glacial age during the

Pleistocene The Pleistocene ( , often referred to as the ''Ice age'') is the geological Epoch (geology), epoch that lasted from about 2,580,000 to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations. Before a change was fina ...

epoch (

ice age An ice age is a long period of reduction in the temperature of Earth's surface and atmosphere, resulting in the presence or expansion of continental and polar ice sheets and alpine glaciers. Earth's climate alternates between ice ages and gree ...

), some 15,000 years ago, sea level was considerably lower. Dean's Blue Hole is roughly circular at the surface, with a diameter ranging from . After descending , the hole widens considerably into a cavern with a diameter of .

References

External links

{{Blue holes Landforms of the Bahamas Sea caves Marine geology Underwater diving sites in the Caribbean Long Island, Bahamas Sinkholes of North America