- 'Weirdest thing I've seen in 18 years at sea' says a ship lieutenant
- Rocks spotted floating 1000km off coast of New Zealand
A huge cluster of floating volcanic rocks covering almost 26,000 square kilometres (10,000 square miles) has been found drifting in the Pacific, the New Zealand Navy said on Friday.
The strange phenomenon, which witnesses said resembled a polar ice shelf, was made up of lightweight pumice expelled from an underwater volcano, the navy said.
An air force plane spotted the rocks on Thursday about 1,000 kilometres (600 miles) offshore from New Zealand and warned a navy warship that it was heading towards them.
An area of floating pumice 250 nautical miles in length and 30 nautical miles wide in the South Pacific ocean
The pumice was found half way between New Zealand and Tonga by the NZ Navy while sailing southwest of Raoul Island
Lieutenant Tim Oscar said that while he knew his ship the HMNZS Canterbury was in no danger from the pumice, which is solidified lava filled with air bubbles, it was still the weirdest thing he's seen in 18 years at sea.
'As far ahead as I could observe was a raft of pumice moving up and down with the swell,' he said.
'The rock looked to be sitting two foot (half a metre) above the surface of the waves and lit up a brilliant while colour in the spotlight. It looked exactly like the edge of an ice shelf.'
Scientists aboard the ship said the pumice probably came from an underwater volcano called Monowai, which has been active recently.
They said the phenomenon was unrelated to increased volcanic activity in New Zealand this week, including an eruption at Mount Tongariro that sent an ash cloud 20,000 feet into the atmosphere.
New Zealand frigates regularly patrol past ice shelves in the Southern Ocean
Sailors aboard the HMSNZS Canterbury thought they were looking at an ice shelf when they saw the floating pumice