NR-1 Sinkhole facts for kids
The NR-1 Sinkhole is a giant hole found deep under the ocean. It's located in the Straits of Florida, about 40 miles (64 kilometers) southwest of Key West, Florida. This amazing sinkhole is super deep, about 1,886 feet (575 meters) underwater! It sits at the bottom of a large underwater slope called the Pourtales Escarpment, which is an area made of very old layers of sand and rock.
A special U.S. Navy submarine named the American submarine NR-1 discovered this sinkhole in October 1994. The submarine was a nuclear-powered research vessel, built to explore and study the ocean floor. The sinkhole was named after this submarine.
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Discovery of the NR-1 Sinkhole
The NR-1 Sinkhole was first spotted using special tools that help scientists "see" the ocean floor. These tools included a side-scan sonar and an echo sounder.
How it was found
- Side-scan sonar: This tool sends out sound waves to the sides of the submarine. These waves bounce off the ocean floor and return, creating a picture of what's down there.
- Echo sounder: This tool sends sound waves straight down. By measuring how long it takes for the sound to bounce back, scientists can figure out the depth of the water and the shape of the seafloor.
After the first discovery in October 1994, scientists wanted to be sure about what they had found. So, they sent the submarine back for a second look in May 1995 to confirm the sinkhole was really there.
Why the NR-1 Sinkhole is Special
The discovery of the NR-1 Sinkhole got scientists very excited because it challenged what they thought they knew about how sinkholes form.
How most sinkholes form
Most sinkholes are believed to form only in places that were once exposed to the air. This means they form on land, or in areas that were dry land a long, long time ago. This happens when water seeps into the ground and dissolves soft rocks like limestone, creating underground caves that eventually collapse.
A new idea about sinkholes
The NR-1 Sinkhole is different. It's so deep underwater that scientists believe this area has never been exposed to the air, not even millions of years ago during a time called the Neogene period. This means the NR-1 Sinkhole is the first clear example that shows karst sinkholes can form entirely underwater. Karst is a type of landscape where the dissolving of soluble rocks (like limestone) creates caves, sinkholes, and other unique features. The NR-1 Sinkhole suggests that these processes can happen even when completely submerged.
