Pumice raft

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Pumice rafts from the eruption of Fukutoku-Okanoba submarine volcano in 1986, seen from a ship The eruption of Fukutoku-Oka-no-Ba 05.jpg
Pumice rafts from the eruption of Fukutoku-Okanoba submarine volcano in 1986, seen from a ship
A piece of pumice Pumice stone444.jpg
A piece of pumice

A pumice raft is a floating raft of pumice created by some eruptions of submarine volcanoes or coastal subaerial volcanoes.

Contents

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 proposed pumice rafts as a possible ideal substrate for the origin of life. [1]

Biologists have suggested that animals and plants have migrated from island to island on pumice rafts. [2] [3]

Notable examples

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. [4] [5]

20th century and onward

Pumice rafts drifted to Fiji in 1979 and 1984 from eruptions around Tonga, and some were reportedly 30 kilometres (19 mi) wide.

Satellite image of a pumice raft near Vava`u, Tonga, in August 2006 Pumice raft.jpg
Satellite image of a pumice raft near Vavaʻu, Tonga, in August 2006

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 pumice stone floating in the water—and then had "sailed into a vast, many-miles-wide belt of densely packed pumice". [6] They went on to witness the ephemeral island known as Home Reef breaching the surface. [7]

A very large pumice raft appeared near New Zealand in August 2012. It was reported to be spread on an area 480 kilometres (300 mi) long and about 50 kilometres (30 mi) wide, with pumice blocks poking up to 60 centimetres (2 ft) above the ocean surface. [8] On 10 August 2012 a raft with an estimated area of 26,000 square kilometres (10,000 sq mi) was observed near Raoul Island, 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 in the Kermadec Islands north of New Zealand. [9] [10] [11] (See: 2012 Kermadec Islands eruption).

In August 2019, a large floating pumice raft covering 150 square kilometres (58 sq mi) was discovered in the tropical Pacific Ocean near Late Island in the Kingdom of Tonga. 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. [12] [13]

See also

Related Research Articles

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Pumice, called pumicite in its powdered or dust form, is a volcanic rock that consists of extremely vesicular rough-textured volcanic glass, which may or may not contain crystals. It is typically light-colored. Scoria is another vesicular volcanic rock that differs from pumice in having larger vesicles, thicker vesicle walls, and being dark colored and denser.

<span class="mw-page-title-main">Raoul Island</span> Volcano in the Kermadec Islands, New Zealand

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<span class="mw-page-title-main">Kermadec Islands</span> Subtropical island arc in the South Pacific Ocean

The Kermadec Islands are a subtropical island arc in the South Pacific Ocean 800–1,000 km (500–620 mi) northeast of New Zealand's North Island, and a similar distance southwest of Tonga. The islands are part of New Zealand. They are 33.6 km2 (13.0 sq mi) in total area and uninhabited, except for the permanently staffed Raoul Island Station, the northernmost outpost of New Zealand.

<span class="mw-page-title-main">Protector Shoal</span> Submarine volcano NW of Zavodovski Island in the South Sandwich Islands

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<span class="mw-page-title-main">Submarine volcano</span> Underwater vents or fissures in the Earths surface from which magma can erupt

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<span class="mw-page-title-main">Fonualei</span> Island in Tonga

Fonualei is an uninhabited volcanic island in the kingdom of Tonga. It 70 km northwest of Vavaʻu and is part of the highly active Kermadec-Tonga subduction zone and its associated volcanic arc, which extends from New Zealand north-northeast to Fiji, and is formed by the subduction of the Pacific Plate under the Indo-Australian Plate. The closest island to Fonualei is Tokū 19.7 km to the southeast.

<span class="mw-page-title-main">Home Reef</span> Ephemeral island in the South Pacific

Home Reef is a volcanic island atop a submarine volcano in Tonga. It is located southwest of Vava'u, between the islands of Kao and Late along the Tofua volcanic arc. The island is ephemeral, and has been repeatedly built and eroded by successive eruptions in 1852, 1857, 1984, 2006, 2022, and 2023.

<span class="mw-page-title-main">Metis Shoal</span> Island in Tonga

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<span class="mw-page-title-main">Hunga Tonga–Hunga Haʻapai</span> Submarine volcano in Tonga

Hunga Tonga–Hunga Haʻapai is a submarine volcano in the South Pacific located about 30 km (19 mi) south of the submarine volcano of Fonuafoʻou and 65 km (40 mi) north of Tongatapu, Tonga's main island. It is part of the highly active Kermadec-Tonga subduction zone and its associated volcanic arc, which extends from New Zealand north-northeast to Fiji, and is formed by the subduction of the Pacific Plate under the Indo-Australian Plate. It lies about 100 km (62 mi) above a very active seismic zone.

<span class="mw-page-title-main">2009 Tonga undersea volcanic eruption</span> Volcanic eruption creating a new land linking Hunga Tonga and Hunga Haʻapai islands

The 2009 Tonga undersea volcanic eruption began on 16 March 2009, near the island of Hunga Tonga, approximately 62 kilometres (39 mi) from the Tongan capital of Nukuʻalofa. The volcano is in a highly active volcanic region that represents a portion of the Pacific Ring of Fire. It is estimated that there are up to 36 undersea volcanoes clustered together in the area.

<span class="mw-page-title-main">2012 Kermadec Islands eruption</span> Major undersea volcanic eruption in the Kermadec Islands of New Zealand

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 density pumice produced by the eruption accumulated as a large area of floating pumice, a pumice raft, that was originally covering a surface of 400 square kilometres, spread to a continuous float of between 19,000 and 26,000 km2 and within three months dispersed to an area of more than twice the size of New Zealand.

<span class="mw-page-title-main">Sandy Island, New Caledonia</span> Non-existent island near New Caledonia

Sandy Island is a phantom island that was charted for over a century as being located near the French territory of New Caledonia between the Chesterfield Islands and Nereus Reef in the eastern Coral Sea. The island was included on many maps and nautical charts from as early as the late 19th century. It was removed from French hydrographic charts in 1974. The island gained wide media and public attention in November 2012 when the R/V Southern Surveyor, an Australian research ship, passed through the area and "undiscovered" it. The island was quickly removed from many maps and data sets, including those of the National Geographic Society and Google Maps.

<span class="mw-page-title-main">Monowai (seamount)</span> Volcanic seamount north of New Zealand

Monowai Seamount is a volcanic seamount to the north of New Zealand. It is formed by a large caldera and a volcanic cone just south-southeast from the caldera. The volcanic cone rises to depths of up to 100 metres (330 ft) but its depth varies with ongoing volcanic activity, including sector collapses and the growth of lava domes. The seamount and its volcanism were discovered after 1877, but only in 1980 was it named "Monowai" after a research ship of the same name.

<span class="mw-page-title-main">2022 Hunga Tonga–Hunga Haʻapai eruption and tsunami</span> Volcanic event in the South Pacific Ocean

In December 2021, an eruption began on Hunga Tonga–Hunga Haʻapai, a submarine volcano in the Tongan archipelago in the southern Pacific Ocean. The eruption reached a very large and powerful climax nearly four weeks later, on 15 January 2022. Hunga Tonga–Hunga Haʻapai is 65 kilometres (40 mi) north of Tongatapu, the country's main island, and is part of the highly active Tonga–Kermadec Islands volcanic arc, a subduction zone extending from New Zealand to Fiji. On the Volcanic Explosivity Index scale, the eruption was rated at least a VEI-5. Described by scientists as a "magma hammer", the volcano at its height produced a series of four underwater thrusts, displaced 10 cubic kilometres (2.4 cu mi) of rock, ash and sediment, and generated the largest atmospheric explosion recorded by modern instrumentation.

Volcano F is a submarine volcano in the Tonga Islands of the South Pacific Ocean. It is located 50 km (31 mi) northwest of Vavaʻu, between Late and Fonualei on the Tofua ridge. It is part of the highly active Kermadec-Tonga subduction zone and its associated volcanic arc, which extends from New Zealand north-northeast to Fiji, and is formed by the subduction of the Pacific Plate under the Indo-Australian Plate.

<span class="mw-page-title-main">Macauley Island</span> Volcanic island in New Zealands Kermadec Islands

Macauley Island is a volcanic island in New Zealand's Kermadec Islands, approximately halfway between New Zealand's North Island and Tonga in the southwest Pacific Ocean. It is part of a larger submarine volcano that features a 10.5 by 7 kilometres wide underwater caldera northwest of Macauley Island. Two islets, Haszard Island and Newcome Rock, lie east offshore of Macauley Island. The island is mostly surrounded by high cliffs that make accessing it difficult; the inland parts are mostly gently sloping terrain covered with ferns and grasses.

References

  1. Martin D. Brasier, Richard Matthewman, Sean McMahon and David Wacey. "Pumice as a Remarkable Substrate for the Origin of Life" Astrobiology. August 31, 2011
  2. New Island and Pumice Raft, Tonga, NASA Earth Observatory photo with commentary, August 2006
  3. Nunn, Patrick D. (2008). Vanished Islands and Hidden Continents of the Pacific. University of Hawai'i Press. p. 59. ISBN   978-0-8248-3219-3.
  4. Seton, M.; Williams, S.; Zahirovic, S.; Micklethwaite, S. (9 April 2013). "Obituary: Sandy Island (1876 –2012)". Eos, Transactions American Geophysical Union. 94 (15): 141–142. Bibcode:2013EOSTr..94..141S. doi: 10.1002/2013EO150001 .
  5. Joel Achenbach (April 4, 2013). "Scientist unravels mystery of Coral Sea's ghostly Sandy Island" . Washington Post. Retrieved May 24, 2021.
  6. "Stone sea and volcano". Fredrik and Crew on Maiken. Blogger. 2006-08-17. Retrieved 2008-11-07.
  7. New Island and Pumice Raft, Tonga, NASA Earth Observatory photo with commentary, November 2006
  8. Space.com, "Source of Mysterious Pumice 'Raft' in Pacific Found, NASA Says", Jeanna Bryner, 14 August 2012
  9. "Vast volcanic 'raft' found in Pacific, near New Zealand". BBC News. 10 August 2012. Retrieved 10 August 2012.
  10. "Pumice raft bigger than area of Israel". The Australian. 10 August 2012.
  11. "'Weirdest thing' floats in South Pacific - CNN.com". CNN. 11 August 2012.
  12. "A Raft of Rock". NASA. 13 August 2019.
  13. "Vast 'pumice raft' found drifting through Pacific Ocean". BBC. 26 August 2019.