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Pumice

From Wikipedia, the free encyclopedia
Not to be confused withpomace.
Specimen of highly porous pumice fromTeidevolcano onTenerife,Canary Islands.Densityof specimen approximately 0.25 g/cm3;scale incentimeters.
Kutkhiny Baty, a pumice rock formation outcrop located 4 km from the source of theOzernaya River(Lake Kurile), near the southern tip of theKamchatka Peninsula,Russia.

Pumice(/ˈpʌmɪs/), calledpumicitein its powdered or dust form, is avolcanic rockthat consists of extremelyvesicularrough-texturedvolcanic glass,which may or may not contain crystals. It is typically light-colored.Scoriais another vesicular volcanic rock that differs from pumice in having larger vesicles, thicker vesicle walls, and being dark colored and denser.[1][2]

Pumice is created when super-heated, highly pressurized rock is rapidly ejected from avolcano.The unusual foamy configuration of pumice happens because of simultaneous rapid cooling and rapid depressurization. The depressurization creates bubbles by lowering thesolubilityof gases (includingwaterandCO2) that are dissolved in the lava, causing the gases to rapidlyexsolve(like the bubbles of CO2that appear when a carbonated drink is opened). The simultaneous cooling and depressurization freeze the bubbles in amatrix.Eruptions under water are rapidly cooled and thelarge volume of pumice createdcan be a shipping hazard for cargo ships.[3]

Properties[edit]

Pumice is composed of highlymicrovesicularglasspyroclasticwith very thin, translucent bubble walls ofextrusiveigneous rock.It is commonly[4]but not exclusively ofsilicicorfelsicto intermediate in composition (e.g.,rhyolitic,dacitic,andesite,pantellerite,phonolite,trachyte), butbasalticand other compositions are known. Pumice is commonly pale in color, ranging from white, cream, blue or grey, to green-brown or black. It forms whenvolcanic gasesexsolving from viscousmagmaform bubbles that remain within the viscous magma as it cools to glass. Pumice is a common product of explosive eruptions (plinianandignimbrite-forming) and commonly forms zones in upper parts of siliciclavas.Pumice has aporosityof 64–85% by volume and it floats on water, possibly for years, until it eventually becomes waterlogged and sinks.[5][6]

Scoriadiffers from pumice in being denser. With larger vesicles and thicker vesicle walls, scoria sinks rapidly. The difference is the result of the lower viscosity of the magma that forms scoria. When larger amounts of gas are present, the result is a finer-grained variety of pumice known aspumicite.Pumicite consists of particles less than 4 mm (0.16 in) in size.[7]Pumice is considered avolcanic glassbecause it has nocrystalstructure. Pumice varies in density according to the thickness of the solid material between the bubbles; many samples float in water. After the explosion ofKrakatoa,rafts of pumicedrifted through the Indian Ocean for up to 20 years, with tree trunks floating among them.[8]In fact, pumice rafts disperse and support several marine species.[9]In 1979, 1984 and 2006, underwater volcanic eruptions nearTongacreated large pumice rafts that floated hundreds of kilometres toFiji.[10]

There are two main forms of vesicles. Most pumice contains tubular microvesicles that can impart a silky or fibrous fabric. The elongation of the microvesicles occurs due toductileelongation in the volcanic conduit or, in the case of pumiceous lavas, during flow. The other form of vesicles are subspherical to spherical and result from highvapor pressureduring an eruption.[11]Reticuliteis a type of basaltic pumice formed in very high lava fountains. It has an extremely low density and is composed of a network of volcanic glass formed when the vesicles have almost completely coalesced.[12]

  • Illustrates the porous nature in detail.
    Illustrates the porous nature in detail.
  • Rocks from the Bishop tuff, uncompressed with pumice on left; compressed with fiamme on right.
    Rocks from theBishop tuff,uncompressed with pumice on left; compressed withfiammeon right.
  • Two layers of pumice, first major phase of the Late-Bronze-Age volcano eruption (~ 1500 BC), southern part of the caldera island Thera/Santorini. The lower layer is finer, almost white and without intrusions.
    Two layers of pumice, first major phase of the Late-Bronze-Age volcano eruption (~ 1500 BC), southern part of thecalderaisland Thera/Santorini.The lower layer is finer, almost white and without intrusions.

Etymology[edit]

Pumice is an igneous rock with a foamy appearance. The name is derived from the Latin wordpumex(meaning "pumice" )[13]which is related to the Latin wordspumameaning "foam".[14]In former times, pumice was called "Spuma Maris", meaning "froth of the sea" in Latin because the frothy material was thought to be hardened sea foam. Around 80 B.C., it was called "lapis spongiae" in Latin for its vesicular properties. Many Greek scholars decided there were different sources of pumice, one of which was in the sea coral category.[15]

Area[edit]

Pumice can be found all around the globe deriving from continental volcanic occurrences and submarine volcanic occurrences. Floating stones can also be distributed by ocean currents.[16]As described earlier pumice is produced by the eruption of explosive volcanoes under certain conditions, therefore, natural sources occur in volcanically active regions. Pumice is mined and transported from these regions. In 2011, Italy and Turkey led pumice mining production at 4 and 3 million tons respectively; other large producers at or exceeding a million tonnes were Greece, Iran, Chile, and Syria. Total world pumice production in 2011 was estimated at 17 million tonnes.[17]

Asia[edit]

There are large reserves of pumice in Asian countries including Afghanistan, Indonesia, Japan, Syria, Iran, and eastern Russia. Considerable amounts of pumice can be found at theKamchatka Peninsulaon the eastern flank of Russia. This area contains 19 active volcanoes and it lies in close proximity with thePacific volcanic belt.Asia is also the site of the second-most dangerous volcanic eruption in the 20th century,Mount Pinatubo,whicherupted on June 12, 1991in thePhilippines.Ash and pumicelapilliwere distributed over a mile around the volcano. These ejections filled trenches that once reached 660 feet deep. So much magma was displaced from the vent that the volcano became a depression on the surface of the Earth.[18]Another well-known volcano that produces pumice isKrakatoa.An eruption in 1883 ejected so much pumice that kilometers of sea were covered in floating pumice and in some areas rose 1.5 meters above sea level.[19]

Europe[edit]

Europe is the largest producer of pumice with deposits in Italy, Turkey, Greece, Hungary, Iceland, and Germany. Italy is the largest producer of pumice because of its numerous eruptive volcanoes. On theAeolian Islandsof Italy, the island ofLipariis entirely made up of volcanic rock, including pumice. Large amounts of igneous rock on Lipari are due to the numerous extended periods of volcanic activity from the LatePleistocene(Tyrrhenian) to the Holocene.[20]

North America[edit]

Pumice can be found all across North America including on theCaribbean Islands.In the United States, pumice is mined inNevada,Oregon,Idaho,Arizona,California,New MexicoandKansas.U.S. production of pumice and pumicite in 2011 was estimated at 380,000 tonnes, valued at $7.7 million with approximately 46% coming from Nevada and Oregon.[17]Idaho is also known as a large producer of pumice because of the quality and brightness of the rock found in local reserves.[21]One of the most famous volcanoes wasMount Mazamathat erupted 7,700 years ago in Oregon and deposited 300 feet of pumice and ash around the vent. The large amount of magma that was erupted caused the structure to collapse, forming a caldera now known asCrater Lake.[18]

South America[edit]

Chileis one of the leading producers of pumice in the world.[22]ThePuyehue-Cordón Caulleare two coalesced volcanoes in theAndesmountains that ejected ash and pumice across Chile andArgentina.A recent eruption in 2011 wreaked havoc on the region by covering all surfaces and lakes in ash and pumice.[23]

Africa[edit]

Kenya,EthiopiaandTanzaniahave some deposits of pumice.[16]

New Zealand[edit]

TheHavre Seamountvolcano produced the largest-known deep ocean volcanic eruption on Earth. The volcanoerupted in July 2012but remained unnoticed until enormous pieces of pumice were seen to be floating on the Pacific Ocean. Blankets of rock reached a thickness of 5 meters.[24]Most of this floating pumice is deposited on the northwest coast ofNew Zealandand thePolynesiaislands.

Mining[edit]

Theminingof pumice is an environmentally friendly process compared with other mining methods because the igneous rock is deposited on the surface of the earth in loose aggregate form. The material is mined by open-pit methods. Soils are removed by machinery in order to obtain more pure quality pumice. Scalping screens are used to filter impure surficial pumice of organic soils and unwanted rocks. Blasting is not necessary because the material is unconsolidated, therefore only simple machinery is used such as bulldozers and power shovels. Different sizes of pumice are needed for specific uses therefore crushers are used to achieve desired grades ranging from lump, coarse, intermediate, fine, and extra fine.[25]

Uses[edit]

Pumice is a very lightweight, porous and abrasive material and it has been used for centuries in the construction and beauty industry as well as in early medicine. It is also used as anabrasive,especially inpolishes,pencilerasers,and the production ofstone-washedjeans.Pumice was also used in the early book-making industry to prepare parchment paper and leather bindings.[26]There is high demand for pumice, particularly for water filtration, chemical spill containment, cement manufacturing,[27]horticulture and increasingly for the pet industry. The mining of pumice in environmentally sensitive areas has been under more scrutiny after such an operation was stopped in the U.S. state of Oregon, at Rock Mesa in the southern part of theThree Sisters Wilderness.[28]

Early medicine[edit]

Pumice has been used in the medicinal industry for more than 2000 years. Ancient Chinese medicine used ground pumice along with groundmicaand fossilized bones added to teas to calm the spirit. This tea was used to treat dizziness, nausea, insomnia, and anxiety disorders. Ingestion of these pulverized rocks was believed to be able to soften nodules and was later used with other herbal ingredients to treat gallbladder cancer and urinary difficulties. In Western medicine, beginning in the early 18th century, pumice ground into a sugar consistency mixed with other ingredients was used to attempt to treat ulcers mostly on the skin and cornea. Concoctions such as these were also used to help wounds scar in a supposedly healthier manner. In approximately 1680 it was noted by an English naturalist that pumice powder was used to promote sneezing.[29]

Personal care[edit]

Pumice soap bars

Pumice has been used as a material in personal care for thousands of years. It is an abrasive material that can be used in powdered form or as a stone to remove unwanted hair or skin. In ancientEgypt,it was common to remove all hair on the body to controlliceand as a form of ritual purification, using creams, razors, and pumice stones.[30]Pumice in powdered form was an ingredient in toothpastes in ancient Rome.[31]Nail care was very important in ancient China; nails were kept groomed with pumice stones, and pumice stones were also used to remove calluses.

It was discovered in a Roman poem that pumice was used to remove dead skin as far back as 100 BC, and likely before then.[32]It has been used throughout many eras since then, including theVictorian Era.Today, many of these techniques are still used; pumice is widely used as a skinexfoliant.Even though hair removal techniques have evolved over the centuries, abrasive material like pumice stones is also still used. "Pumice stones" are often used in beauty salons during thepedicureprocess to remove dry and excess skin from the bottom of the foot as well ascalluses.

Finely ground pumice has been added to sometoothpastesas a polish, similar to Roman use, and easily removesdental plaquebuild-up. Such toothpaste is too abrasive for daily use. Pumice is also added to heavy-duty hand cleaners (such aslava soap) as a mild abrasive. Some brands ofchinchilladust bathare formulated with powdered pumice. Old beauty techniques using pumice are still employed today but newer substitutes are easier to obtain.

Cleaning[edit]

Bar of solid pumice stone

Pumice stone, sometimes attached to a handle,[33]is an effective scrubbing tool for removal of limescale, rust, hard water rings, and other stains on porcelain fixtures in households (e.g., bathrooms). It is a quick method compared to alternatives like chemicals orvinegarandbaking sodaorborax.

Horticulture[edit]

Good soil requires sufficient water and nutrient loading as well as little compaction to allow easy exchange of gases. The roots of plants require continuous transportation ofcarbon dioxideandoxygento and from the surface. Pumice improves the quality of soil because of its porous properties; water and gases can be transported easily through the pores and nutrients can be stored in the microscopic holes. Pumice rock fragments are inorganic therefore no decomposition and little compaction occur.

Another benefit of this inorganic rock is that it does not attract or hostfungiorinsects.As drainage is very important in horticulture, with the presence of pumicetillageis much easier. Pumice usage also creates ideal conditions for growing plants likecactiandsucculentsas it increases the water retention in sandy soils and reduces the density ofclayeysoils to allow more transportation of gases and water. The addition of pumice to soil improves and increases vegetative cover as the roots of plants make slopes more stable therefore it helps reduceerosion.It is often used on roadsides and ditches and commonly used in turf and golf courses to maintain grass cover and flatness that can degrade due to large amounts of traffic and compaction. Chemically pumice ispHneutral, neitheracidicnoralkaline.[34]In 2011, 16% of pumice mined in the United States was used for horticultural purposes.[17]

Pumice contributes to soil fertility in areas where it is naturally present in the soil due to volcanic activity. For example, in theJemez Mountainsof New Mexico, theAncestral Puebloanssettled on "pumice patches" of theEl Cajete Pumicewhich likely retained a greater amount of moisture and was ideal for farming.[35]

Construction[edit]

Pumice is widely used to make lightweightconcreteandinsulativelow-densitycinder blocks.The air-filled vesicles in this porous rock serve as a good insulator.[18]A fine-grained version of pumice calledpozzolanis used as an additive in cement and is mixed withlimeto form a light-weight, smooth, plaster-like concrete. This form of concrete was used as far back asRomantimes. Roman engineers utilized it to build the huge dome of thePantheonwith increasing amounts of pumice added to concrete for higher elevations of the structure. It was also commonly used as a construction material for manyaqueducts.

One of the main uses of pumice currently in the United States is manufacturing concrete. This rock has been used in concrete mixtures for thousands of years and continues to be used in producing concrete, especially in regions close to where this volcanic material is deposited.[36]

New studies prove a broader application of pumice powder in the concrete industry. Pumice can act as a cementitious material in concrete and researchers have shown that concrete made with up to 50% pumice powder can significantly improve durability yet reduce greenhouse gas emissions and fossil fuel consumption.[27]

See also[edit]

References[edit]

  1. ^Jackson, J.A., J. Mehl, and K. Neuendorf (2005)Glossary of GeologyAmerican Geological Institute, Alexandria, Virginia. 800 pp.ISBN0-922152-76-4
  2. ^McPhie, J., M. Doyle, and R. Allen (1993)Volcanic Textures A guide to the interpretation of textures in volcanic rocksCentre for Ore Deposit and Exploration Studies, University of Tasmania, Hobart, Tasmania..198 pp.ISBN9780859015226
  3. ^Redfern, Simon."Underwater volcano creates huge floating islands of rock, disrupts shipping".Phys.org.Omicron Technology Ltd.Retrieved25 April2014.
  4. ^Venezia, A.M.; Floriano, M.A.; Deganello, G.; Rossi, A. (July 1992). "Structure of pumice: An XPS and 27Al MAS NMR study".Surface and Interface Analysis.18(7): 532–538.doi:10.1002/sia.740180713.
  5. ^Lockwood, J.P.; Hazlett, R.W. (2010).Volcanoes: Global Perspectives.Chichester: Wiley-Blackwell. pp. 184–185.ISBN978-1-4051-6249-4.
  6. ^Fauria, Kristen E.; Manga, Michael; Wei, Zihan (February 2017)."Trapped bubbles keep pumice afloat and gas diffusion makes pumice sink".Earth and Planetary Science Letters.460:50–59.Bibcode:2017E&PSL.460...50F.doi:10.1016/j.epsl.2016.11.055.
  7. ^Crangle, R. Jr. (November 2015)."Mineral resource of the month: Pumice and pumicite".Earth.Retrieved8 January2021.
  8. ^De Vantier, L.M. (1992)."Rafting of tropical marine organisms on buoyant coralla".Marine Ecology Progress Series.86:301–302.Bibcode:1992MEPS...86..301D.doi:10.3354/meps086301.Trunks and pumice that washed ashore at Keeling Atoll in the early 1900s had been drifting for some 20 years, since the eruption of Krakatoa 1000 km to the northeast in 1883 (Wood-Jones1912)
  9. ^Bryan, S.E.; A. Cook; J.P. Evans; P.W. Colls; M.G. Wells; M.G. Lawrence; J.S. Jell; A. Greig; R. Leslie (2004)."Pumice rafting and faunal dispersion during 2001–2002 in the Southwest Pacific: record of a dacitic submarine explosive eruption from Tonga"(PDF).Earth and Planetary Science Letters.227(1–2): 135–154.Bibcode:2004E&PSL.227..135B.doi:10.1016/j.epsl.2004.08.009.Archived fromthe original(PDF)on 2008-07-29.Retrieved2007-07-14.The abundance and variety of fouling taxa, coupled with the long dispersal trajectory (> 3500 km) and period of pumice flotation (≥ 1 year), confirm the importance of sea-rafted pumice as a long-distance dispersal mechanism for marine organisms
  10. ^"New Island and pumice raft in the Tongas".NASA Earth Observatory.National Aeronautics and Space Administration.16 November 2006.Retrieved23 October2016.
  11. ^Fisher, R.V.; Schmincke, H.-U. (1984).Pyroclastic rocks.Berlin: Springer-Verlag. pp. 103, 197.ISBN3540127569.
  12. ^Gundy, James Van (1 June 2010)."Reticulite".Earth Science Picture of the Day.Universities Space Research Association.Retrieved5 August2022.
  13. ^"Pumice".Merriam-Webster Dictionary.Merriam-Webster.Retrieved23 February2022.
  14. ^"Spume".Merriam-Webster Dictionary.Merriam-Webster.Retrieved23 February2022.
  15. ^Duffin, Christopher J. (1 January 2012)."History of the pharmaceutical use of pumice"(PDF).Geological Society, London, Special Publications.375:157–169.doi:10.1144/SP375.8.S2CID129854945.
  16. ^ab"What is Pumice?".WorldAtlas.28 July 2017.
  17. ^abcCrangle, Robert D. Jr. (January 2012)."Pumice and pumicite - USGS Mineral Resources Program"(PDF).United States Geological Survey.Retrieved25 November2018.
  18. ^abc"Pumice: Igneous Rock - Pictures, Definition & More".geology.
  19. ^"Pumice | volcanic glass".Encyclopedia Britannica.22 November 2023.
  20. ^Liguori, V.; Sciorta, R.; Ruisi, V. (1 December 1984). "The pumice aggregates of Lipari Island (Aeolian Isles-Italy)".Bulletin of the International Association of Engineering Geology.30(1): 431–434.Bibcode:1984BIAEG..30..431L.doi:10.1007/BF02594356.S2CID127008263.
  21. ^"What is Pumice: Origin of Pumice: From Stone to Refined Pumice Powder".hesspumice.
  22. ^Bolen, Wallace."Pumice and Pumicite"(PDF).
  23. ^Taylor, Alan."Volcanic Ash and Pumice From Puyehue - The Atlantic".theatlantic.
  24. ^"Havre - the world's largest deep ocean volcanic eruption".Radio New Zealand.12 June 2018.
  25. ^Austin, George S."Pumice Mining and Environmental Concerns in New Mexico"(PDF).
  26. ^Duffin, Christopher J. (1 January 2012)."History of the pharmaceutical use of pumice"(PDF).Geological Society, London, Special Publications.375:157–169.doi:10.1144/SP375.8.S2CID129854945.
  27. ^abAskarian, Mahya; Fakhretaha Aval, Siavash; Joshaghani, Alireza (22 January 2019). "A comprehensive experimental study on the performance of pumice powder in self-compacting concrete (SCC)".Journal of Sustainable Cement-Based Materials.7(6): 340–356.doi:10.1080/21650373.2018.1511486.S2CID139554392.
  28. ^The Oregon Encyclopedia. Michael McCloskey (Sierra Club 2005)
  29. ^Duffin, Christopher J. (1 January 2012)."History of the pharmaceutical use of pumice"(PDF).Geological Society, London, Special Publications.375:157–169.doi:10.1144/SP375.8.S2CID129854945.
  30. ^Sherrow, Victoria (2006).Encyclopedia of hair: a cultural history.Westport, Conn.: Greenwood Press. pp. 112–113.ISBN9780313331459.
  31. ^Fischman, Stuart L. (October 1997)."The history of oral hygiene products: how far have we come in 6000 years?".Periodontology 2000.15(1): 7–14.doi:10.1111/j.1600-0757.1997.tb00099.x.PMID9643227.
  32. ^Duffin, Christopher J. (1 January 2012)."History of the pharmaceutical use of pumice"(PDF).Geological Society, London, Special Publications.375:157–169.doi:10.1144/SP375.8.S2CID129854945.
  33. ^"Amazon: Powerhouse Pumice Toilet Bowl Cleaning Stone with Handle (2-Pack) – Removes Stains, Limescale, Hard Water Rings, Calcium Buildup, Iron and Rust: Home & Kitchen".amazon.Retrieved2021-05-15.
  34. ^"Improving Soil and other Horticultural Use for Natural Pumice".hesspumice.Archived fromthe originalon 2020-03-05.Retrieved2019-04-04.
  35. ^Gauthier, Rory; Powers, Robert; Herhahn, Cynthia; Bremer, Mike; Goff, Fraser (2007)."Dry farming El Cajete Pumice: Pueblo farming strategies in the Jemez Mountains, New Mexico"(PDF).New Mexico Geological Society Field Conference Series.58:469–474.Retrieved10 January2021.
  36. ^Grasser, Klaus.Building with Pumice(PDF).p. 64.Retrieved23 March2019.

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