Giant Underwater Sinkhole Discovered in the Great Barrier Reef
Hannah Osborne
NewsweekSeptember 29, 2017
A marine biologist claims to have discovered a huge underwater sinkhole—or blue hole—in the Great Barrier Reef.
Blue holes are large marine sinkholes that mostly formed during past ice ages when sea levels were far lower—this mean they were subject to the same erosion from rain and chemical weathering as any other area. After being submerged, the erosion ceased, and the deep blue caverns were left.
https://www.yahoo.com/news/giant-underwater-sinkhole-discovered-great-122251112.html