Great Blue Hole

The Great Blue Hole could be a large submarine depression off the coast of Central American nation. It lies near the center of beacon light Reef, a small coral reef seventy kilometre (43 mi) from the solid ground and Central American nation town. The hole is circular in shape, over 300 m (984 ft) across and 124 m (407 ft) deep. It was formed throughout many episodes of quaternary glaciation once ocean levels were abundant lower. Analysis of stalactites found in the Great Blue Hole shows that formation happened 153,000; 66,000; 60,000; and 15,000 years ago. As the ocean began to rise again, the cave was flooded. The Great Blue Hole could be a a part of the larger Central American nation coral reef Reserve System, a World Heritage Site of the United Nations academic, Scientific and Cultural Organization (UNESCO).

Exploration and name

This site was created far-famed by Jacques Jacques Costeau, who declared it one of the highest 10 skin-dive sites within the world. In 1971 he brought his ship, the Calypso, to the hole to chart its depths. Investigations by this expedition confirmed the hole's start as typical karst limestone formations, formed before rises in ocean level in a minimum of four stages, leaving ledges at depths of 21 m (69 ft), 49 m (161 ft), and 91 m (299 ft). Stalactites were retrieved from submerged caves, affirming their previous formation above ocean level. Some of these stalactites were also off-vertical by 5˚ in an exceedingly consistent orientation, indicating that there had also been some past geologic shift and tilting of the underlying highland, followed by a long period within the current plane.

Initial measured depth of Great Blue Hole was 125 m (410 ft) that is the most frequently cited depth up to the present day. An expedition by the Cambrian Foundation in 1997 calculated the hole's depth as 124 m (407 ft) at its deepest purpose.