Great Blue Hole

The Great Blue Hole is an underwater cave off the coast of Belize. It is near the center of the Lighthouse Reef, a small atoll off the mainland coast. It has been an attraction for sport divers since Jacques-Yves Cousteau came to measure the exact depth with his ship Calypso in 1971.

The Great Blue Hole is a large sinkhole or "blue hole" off the coast of Belize. It is located near the center of the Lighthouse Reef, a small atoll located 100 kilometers from the mainland coast and Belize City.

Great Blue Hole, located in the center of Lighthouse Reef, an atoll as part of the Belize Barrier Reef. The hole is a circular karst funnel with a diameter of 300 meters, extending to a depth of 124 meters.

The 'big blue hole' is almost perfectly circular, with a diameter of 300 meters and a depth of 124 meters. During the last ice age, when the sea level was not that high, it was a limestone cave, the roof of which collapsed later.

The hole is circular in shape, and is more than 300 meters wide and 123 meters deep. When the glaciations ended, or the last Ice Age, 12,000 years ago, the sea level rose, the caverns flooded, the deck collapsed and formed this chasm that fascinates divers because it houses many species of marine beings (fish, sponges and corals). It is believed to be the largest phenomenon in the world of its kind. The Great Blue Hole is part of the Reserve System Barrier Reef of Belize, World Heritage of UNESCO.

This geological formation was originally a system of limestone caves, formed during the last ice age. The sea level then was much lower, but when the ocean rose and the arch of the flooded cave collapsed, a karst funnel formed - a fairly common landform along the coast of Belize.

The blue hole became famous thanks to the French explorer Jacques-Yves Cousteau, who included it in the list of 10 best places in the world for diving. In 1972, on his ship Calypso, he measured the depth of the hole and confirmed the theory of its formation. Having descended into single- hole submarines, the expedition discovered massive stalactites, some of which were located at an angle of 10–13 ° to the vertical, indicating a geological shift and inclination of the underlying plateau.

Despite the inaccessibility of the place (the distance from the city of Belize is about 96 km), the Great Blue Hole is a popular diving site for recreational diving. Divers can come across several interesting species of fish, including a giant grouper, nanny sharks and several species of reef sharks, such as the Caribbean reef shark.

An analysis of the ratio of titanium and aluminum in sedimentary rocks in lagoons adjacent to the karst failure showed that the times between 800 and 900 years and between 1000 and 1100 years were extremely dry periods on the Yucatan, leading to the decline of the ancient Mayan civilization.

Exploration

This site became famous for Jacques-Yves Cousteau (French diver), who made a first dive in 1960 and declared this place as one of the ten best dive sites in the world. In 1971, Cousteau took his ship, the Calypso, to the hole to trace its depths. The investigations of this expedition confirmed the origin of the hole as typical karst limestone formations, constituted before the sea level rises in at least four stages, leaving projections with depths of 21, 49 and 91 meters. The stalactites were recovered from submerged caves, confirming their previous formation above sea level. Some of these stalactites are outside the vertical of 10° -13°, in a coherent orientation, indicating that there has also been some geological movement and an inclination of the underlying platform, followed by a long period in the current plane.

Tourism

This is a popular place among recreational divers, who are attracted by the opportunity to dive in crystal clear waters and encounter several species of fish, including giant groupers, nurse sharks, Caribbean reef shark and blacktip shark. Other shark species have been seen, such as the bull shark and hammerhead shark, but sightings are not frequent. Usually, diving trips to the great blue hole are full-day excursion, which includes diving into the blue hole and two other dives in nearby reefs. Caves of similar formation, such as that of the great blue hole, are well known on the coasts of Belize, and on the Yucatan Peninsula, where they are known as "cenotes".

Coordinates

17°18′55″N 87°32′4″W