|Pumice collected from beach on Norfolk Island (May 2017)|
Having recently visited Norfolk Island (located in the S. Pacific midway between Australia and New Zealand) I was struck by the amount of pumice on the beaches and was told it came from an underwater volcano off New Zealand.
It probably relates to a major undersea volcano, the previously little-known Havre Seamount in the Kermadec Islands of New Zealand, which erupted in 2012.
|A raft of pumice floating on the sea|
The huge volume of molten rock, produced by the eruption, resulted in a large area of floating pumice known as a PUMICE RAFT. This originally covered a surface of 400 square kilometres (150 square miles).
|The raft divided by a boat sailing through|
The thickness of the raft may have been as great as 3.5mt (11ft) but reduced to around 0.5mt (1ft 8in) within a month. It soon spread to a continuous float of between 7,500 and 10,000 sq. miles (19,000 and 26,000km2) and within three month dispersed to an area of more than twice the size of New Zealand.
|Beach at Norfolk Island dotted with pumice|
Reports followed of pumice being found of the beaches of Tasmania and eastern Australia.
Dr Carey University of Tasmania) said pumice rafts were believed to have been a primary means for the transport of sedentary marine species between continents in prehistoric times.
|Huge raft see from space|
Photos of the PUMICE RAFT taken after a volcanic eruption in the South Pacific give an indication of its immense size both from water level and from space.
(Courtesy of the USGS and Smithsonian Institute).