A naval officer calls this "the weirdest thing I've seen in 18 years at sea"S

The Royal New Zealand Navy has discovered 7500 square miles of the lightweight stone pumice floating in the South Pacific. New Zealand's Scoop reports that Royal Australian Navy Lieutenant Tim Oscar called it "the weirdest thing I've seen in 18 years at sea." Oscar went on to tell Scoop:

The lookout reported a shadow on the ocean ahead of us so I ordered the ship's spotlight to be trained on the area. As far ahead as I could observe was a raft of pumice moving up and down with the swell. The rock looked to be sitting two feet above the surface of the waves, and lit up a brilliant white colour in the spotlight. It looked exactly like the edge of an ice shelf. I knew the pumice was lightweight and posed no danger to the ship. None the less it was quite daunting to be moving toward it at 14 knots. It took about 3 - 4 minutes to travel through the raft of pumice and as predicted there was no damage. As we moved through the raft of pumice we used the spotlights to try and find the edge - but it extended as far as we could see.

It turns out, after examination over the weekend, that the pumice covers 7500 square miles. This stone is so lightweight that it can float on water.

Here is a brief shot of the pumice from a plane. It's likely the rocks are the result of an underwater volcano; when lava cools rapidly, it turns to pumice. So it's possible that an enormous volcano has been going off, and our only hint of it was this huge field of pumice. Local scientists say there is an active underwater volcano, Monowai, which might be the source of the extraordinary phenomenon.