NR-1 Sinkhole interest, as sinkholes are generally believed to form only in environments which are subaerial, or exposed to the air. In contrast, the NR-1 Sinkhole is believed to be too deep underwater for the area to have been exposed to the air during formation in the Neogene. It was the first documented evidence suggesting that it is possible for karst sinkholes to form entirely underwater. NR-1 Sinkhole The NR-1 Sinkhole is a giant underwater sinkhole located in the Straits of Florida southwest of Key West, Florida. It is found at an approximate depth of of water at the foot of the
Sinkhole through these volcanic deposits and mechanically washed fine volcanic materials out of them, then progressively eroded and removed coarser materials. Eventually, these underground voids became large enough that their roofs collapsed to create large holes. Some of the largest sinkholes in the world are: Sinkhole A sinkhole, also known as a cenote, sink, sink-hole, swallet, swallow hole, or doline (the different terms for sinkholes are often used interchangeably), is a depression or hole in the ground caused by some form of collapse of the surface layer. Most are caused by karst processes—for example, the chemical dissolution of carbonate rocks or