Dean's Blue Hole
In April 2010, William Trubridge broke a free-diving world record in the blue hole reaching a depth of 92 metres (302 ft) without the use of fins (Constant Weight Without Fins). On 14 December 2010, he swam to a depth of 101 metres on a single breath using only his hands and feet for propulsion.
Blue hole is a term which often is given to sinkholes filled with water, with the entrance below the water level. They can be formed in different karst processes, for example, by the rainwater soaking through fractures of limestone bedrock onto the watertable. Sea level here has changed: for example, during the glacial age during the Pleistocene epoch (ice age), some 15,000 years ago, sea level was considerably lower. The maximum depth of most other known blue holes and sinkholes is 110 metres (360 ft), which makes the 202 metres (663 ft) depth of Dean's Blue Hole quite exceptional.
Dean's Blue Hole is roughly circular at the surface, with a diameter ranging from 25 to 35 metres (82–115 ft). After descending 20 metres (66 ft), the hole widens considerably into a cavern with a diameter of 100 metres (330 ft).
Some water-filled sinkholes are deeper than Dean's Blue Hole, Zacatón in Mexico (335 metres (1,099 ft)) and Pozzo del Merro in Italy (392 metres (1,286 ft)) among them. Dean's Blue Hole though is the deepest known sinkhole with entrance below the sea level.
- "Dean's Blue Hole". Wondermondo. 2010-07-17. Retrieved 2010-07-18.
- Further reading
- Wilson, William L. (1994). "Morphometry and Hydrology of Dean's Blue Hole, Long Island". Bahamas Journal of Science 2 (1): 10–14.
- Dean's Blue Hole entry and exact location on Bloosee
- The Blue Holes Foundation
- Vertical Blue
- Underwater base jump into blue hole (Guillame Nery, Julie Gautier)