An underwater mission at the bottom of Belize's Big Blue Hole has generated the very first map of what it looks like inside.
The sonar scans were carried out on one of the largest wells in the world, measuring 300 meters wide and about 125 meters deep.
This three-week mission allowed researchers to gather enough data to generate a 3D image as well as images of detail never seen before.
This includes stalactites, ice-shaped mineral formations encrusted in marine growth near the bottom, as well as a conch "cemetery" created by thousands of shells falling into the abyss.
The gaping mouth is also filled with hydrogen sulphide – a foul-smelling, odorous, toxic, flammable and highly corrosive gas – and its deepest depths are completely oxygen-free.
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The map of the last expedition is the first ever produced from the Belize Blue Hole and was carried out using a military grade sonar technology. It captures all the diameter and depth of the hole, which measures 984 feet in diameter and 410 feet deep. Divers also discovered new features inside, including a "conch cemetery" and stalactite caves never seen before.
The three-week mission allowed the team to collect enough high resolution images to generate a 3D image and find new discoveries inside the hole. The Blue Hole was once on land but was submerged about 10,000 years ago
The expedition, funded in part by Virgin founder Richard Branson, took place in a three-man submarine under the direction of Erika Bergman, oceanographer and chief pilot of the mission.
"The aptly named Great Blue Hole is a collapsed cave, filled with stalactite caves and built from layers of fine limestone walls and rougher calcium carbonate," said Ms. Bergman, writing on a Southern website blog Fried Science.
"Thanks to various sonar heads used successively during the expedition, we were able to create a high-resolution, three-dimensional sonar image of the interior of the Great Blue Hole. & # 39;
Bergman described the depth of the hole as "another world", describing unpublished details, including the stalactites that fill the cave.
"Some of the targets on which we particularly wanted to study in detail were the stalactite caverns from a depth of 130 to 160 feet, formed when the sea level was 500 feet lower and that it was s & # 39; It was a dry cave, "she added.
"These huge stalactites are now fully integrated with marine growth."
She also noted a number of other memorable features, including a "conch graveyard" and wrote about diving into "the acid" in the deepest layers of the hole.
The team observed hundreds of dead conch shells that, they said, had fallen into the hole and could not escape its steep walls.
There is also a thick layer of hydrogen sulphide about 300 feet from the Grand Hole Blue that the team's submarine had to penetrate to reach the ocean floor.
However, everything they saw was not identifiable. Mrs. Bergman spoke of "tracks" at the very base of the hole, an enigma that the team could not decipher.
The scans were done with a professional sonographer on board who used military-grade technology to capture high-resolution sonar scanners by bouncing sound waves onto cave walls surrounding the submarine.
The expedition, which was attended by Virgin founder Richard Branson, took place in a three-man submarine (photo) sailed by Erika Bergman, oceanographer and chief pilot of the mission.
Erika Bergman, pilot of the submarine assigned to the mission, wrote on a blog published on the website of Southern Fried Chicken: "The aptly named Grand Hole Blue is a cave collapsed, filled with caverns of stalactites and built from thin limestone walls and more rugged calcium carbonate ".
Sir Richard Branson's three-week mission enabled researchers to collect enough high-resolution images to generate a 3D image and uncover details never seen before. This includes stalactites, ice-shaped mineral formations near the bottom, and a conch cemetery (photo) created by thousands of shells falling into
Virgin founder Richard Branson (left) is responsible for the Belize Offshore Project, which is exploring the complex system of caves. Fabien Cousteau, a specialist in ocean protection, documentary filmmaker and grandson of the famous explorer Jacques Cousteau, joins Branson (right).
In addition to the toxic layer of hydrogen sulphide, the team found traces of human pollution at the bottom of the hole in December, including plastics from water bottles found 120 meters below the surface of the ocean.
Branson wrote about it on his blog about the expedition: & # 39; TThe real monsters that face the ocean are climate change – and plastics.
"Unfortunately, we saw plastic bottles at the bottom of the hole, a real plague of the ocean. We all have to get rid of disposable plastics.
He warned against similar submersion events in the present, calling what he saw at the bottom of the hole "the darkest reminders of the danger of climate change that I've ever seen".
"It's proof that the oceans can rise quickly and catastrophically," he added.
A thick layer of hydrogen sulphide was found at the bottom of the hole. The chemical is a foul-smelling, colorless, toxic, flammable and extremely corrosive gas. It was discovered at a depth of 300 feet and the team reported diving directly.
The blue hole was once on land, but it was submerged about 10,000 years ago at the end of the last ice age.
The expedition to the popular tourist site deployed two submarine submarines of three men.
Branson and Fabien Cousteau – an advocate of ocean protection, documentary filmmaker and grandson of the famous explorer Jacques Cousteau – who also participated in the previous dive, spent hours at the bottom of the Blue Hole.
Two large floating vessels were available for research and logistical support.
It is hoped that the information gathered during the expedition will also help to better understand the impact of climate change on the planet over millennia.
The Branson Expedition to Belize also supported Ocean Unite, an organization that brings together leaders and voices to promote ocean conservation. They are campaigning to protect at least 30% of the ocean by 2030
The submersibles allowed the team to spend more time at the bottom of the Blue Hole. This is the first time scientists have correctly explored the Blue Hole
Cousteau's links with the Blue Hole go beyond professional interests.
In 1971, his grandfather, the famous French explorer-explorer Jacques Cousteau, brought his research vessel Calypso 70 km off the coast of Belize to explore the magnificent 300-meter long sinkhole.
The team of Jaques Cousteau had discovered that the Blue Hole, the largest sinkhole in the world and one of the main tourist attractions of Belize, was actually a submerged cave that had formed during tens of thousands of years.
While divers had already reached the bottom of the Blue Hole, total darkness and harsh conditions had limited their ability to collect scientific data.
The last expedition was the first time that modern technology, in the form of a submarine, gave a scientific team the time and access needed to study in detail the geological formation.
Mr. Cousteau said: "There are still a lot of discoveries to be made, including sediment research, observation of wall variations, oxygen content and CO²."
"There is a whole list of things we are going to do here that have not been done.
JACQUES COUSTEAU AND THE GREAT BLUE HOLE
The Great Blue Hole was made famous by the French ocean explorer Jacques Cousteau, who declared it one of the top five scuba diving sites in the world.
He brought his renowned research vessel, the Calypso, to study the depths of the chasm in 1972.
The expedition found submerged stalactites in the hole and was able to conclude that the Blue Hole had formed before sea level rise.
The Great Blue Hole was made famous by the French ocean explorer Jacques Cousteau (left), who declared it one of the top five scuba diving sites in the world. He brought his renowned research vessel, the Calypso, to study the depths of the chasm in 1972.
Investigations of this expedition confirmed the origin of the hole as a typical karst limestone formation, formed before sea level rises at least in four stages, leaving ledges at 21 m (69 ft) depths. , 49 m (161 ft) and 91 m (299 km). ft).
Stalactites were recovered from submerged caves, confirming their previous formation above sea level.
Some of these stalactites were also 5 ° offset from the vertical, indicating that there had been some earlier geological changes and tilting of the underlying plateau, followed by a long time in the current plan.
The tilt indicates that it was a movement of the earth, rather than a rise in sea level alone.