A pumice raft is a floating raft of

pumice Pumice (), called pumicite in its powdered or dust form, is a volcanic rock that consists of highly vesicular rough-textured volcanic glass, which may or may not contain crystals. It is typically light-colored. Scoria is another vesicular v ...

created by some eruptions of

submarine volcano Submarine volcanoes are underwater vents or fissures in the Earth's surface from which magma can erupt. Many submarine volcanoes are located near areas of tectonic plate formation, known as mid-ocean ridges. The volcanoes at mid-ocean ri ...

es or coastal subaerial volcanoes. Biologists suggest that animals and plants have migrated from island to island on pumice rafts. Pumice rafts have unique characteristics such as the highest surface-area-to-volume ratio known for any rock type, long term flotation and beaching in the tidal zone, exposure to a variety of conditions, including dehydration, and an ability to absorb many potentially advantageous elements/compounds. For at least these reasons, astrobiologists have hypothetically proposed pumice rafts as an ideal substrate for the

origin of life In biology, abiogenesis (from a- 'not' + Greek bios 'life' + genesis 'origin') or the origin of life is the natural process by which life has arisen from non-living matter, such as simple organic compounds. The prevailing scientific hypothes ...

Notable examples

Pumice rafts drifted to

Fiji Fiji ( , ,; fj, Viti, ; Fiji Hindi: फ़िजी, ''Fijī''), officially the Republic of Fiji, is an island country in Melanesia, part of Oceania in the South Pacific Ocean. It lies about north-northeast of New Zealand. Fiji consis ...

in 1979 and 1984 from eruptions around Tonga, and some were reportedly wide. Volcanic activity in the South Pacific near Tonga on August 12, 2006 caused the emergence of a new island. The crew of the ''Maiken'', a yacht that had left the northern Tongan islands group of Vava'u in August, reported that they had seen streaks of light, porous

stone floating in the water—and then had "sailed into a vast, many-miles-wide belt of densely packed pumice". They went on to witness the

ephemeral Ephemerality (from the Greek word , meaning 'lasting only one day') is the concept of things being transitory, existing only briefly. Academically, the term ephemeral constitutionally describes a diverse assortment of things and experiences, f ...

island known as Home Reef breaching the surface. A very large pumice raft appeared near

New Zealand New Zealand ( mi, Aotearoa ) is an island country in the southwestern Pacific Ocean. It consists of two main landmasses—the North Island () and the South Island ()—and over 700 smaller islands. It is the sixth-largest island coun ...

in August 2012. It was reported to be spread on an area long and about wide, with pumice blocks poking up to above the ocean surface. On 10 August 2012 a raft with an estimated area of was observed near

Raoul Island Raoul Island (''Sunday Island'') is the largest and northernmost of the main Kermadec Islands, south south-west of 'Ata Island of Tonga and north north-east of New Zealand's North Island. It has been the source of vigorous volcanic activity ...

, north-east of New Zealand by the Royal New Zealand Navy. A possible source for the pumice was the July 2012 eruption of Havre

seamount A seamount is a large geologic landform that rises from the ocean floor that does not reach to the water's surface (sea level), and thus is not an island, islet or cliff-rock. Seamounts are typically formed from extinct volcanoes that rise a ...

in the Kermadec Islands north of New Zealand. (''See:

2012 Kermadec Islands eruption The 2012 Kermadec Islands eruption was a major undersea volcanic eruption that was produced by the previously little-known Havre Seamount near the L'Esperance and L'Havre Rocks in the Kermadec Islands of New Zealand. The large volume of low ...

).'' In August 2019, a large floating pumice raft covering was discovered in the tropical Pacific Ocean near Late Island in the

Kingdom of Tonga Tonga (, ; ), officially the Kingdom of Tonga ( to, Puleʻanga Fakatuʻi ʻo Tonga), is a Polynesian country and archipelago. The country has 171 islands – of which 45 are inhabited. Its total surface area is about , scattered over in ...

. Sailors described a “rubble slick made up of rocks from marble to basketball size such that water was not visible,” as well as a smell of sulfur. Sandy Island, a non-existent island near New Caledonia, was reported in 1876 by the whaling ship ''Velocity'' and subsequently included on some maps well into the 20th century. According to a team of University of Sydney scientists, it is possible that this false report may have been occasioned by pumice rafts being mistaken by the ''Velocity'' for dry land.

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Pumice raft in South China Sea near Vietnam in August 1986Pumice rafts in Fiji produced by the eruption of Home Reef volcano, Tonga in 2006
Volcanoes Volcanology Rafts Floating islands

Notable examples

See also

References

External links