Pumice
Pumice ( /ˈpʌmɪs/), 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 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 a
Properties
Pumice is composed of highly
Scoria differs 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 as pumicite. Pumicite consists of particles less than 4 mm (0.16 in) in size.[7] Pumice is considered a volcanic glass because it has no crystal structure. Pumice varies in density according to the thickness of the solid material between the bubbles; many samples float in water. After the explosion of Krakatoa, rafts of pumice drifted 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 near Tonga created large pumice rafts that floated hundreds of kilometres to Fiji.[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 to
-
Illustrates the porous nature in detail.
-
Rocks from theBishop tuff, uncompressed with pumice on left; compressed with fiammeon right.
Etymology
Pumice is an igneous rock with a foamy appearance. The name is derived from the Latin word pumex (meaning "pumice")[13] which is related to the Latin word spuma meaning "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
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
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 the Kamchatka Peninsula on the eastern flank of Russia. This area contains 19 active volcanoes and it lies in close proximity with the Pacific volcanic belt. Asia is also the site of the second-most dangerous volcanic eruption in the 20th century, Mount Pinatubo, which erupted on June 12, 1991 in the Philippines. Ash and pumice lapilli were 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 is Krakatoa. 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
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 the Aeolian Islands of Italy, the island of Lipari is 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 Late Pleistocene (Tyrrhenian) to the Holocene.[20]
North America
Pumice can be found all across North America including on the
South America
Chile is one of the leading producers of pumice in the world.[22] The Puyehue-Cordón Caulle are two coalesced volcanoes in the Andes mountains that ejected ash and pumice across Chile and Argentina. A recent eruption in 2011 wreaked havoc on the region by covering all surfaces and lakes in ash and pumice.[23]
Africa
Kenya, Ethiopia and Tanzania have some deposits of pumice. [16]
New Zealand
The Havre Seamount volcano produced the largest-known deep ocean volcanic eruption on Earth. The volcano erupted in July 2012 but 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 of New Zealand and the Polynesia islands.
Mining
The mining of 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
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 an abrasive, especially in polishes, pencil erasers, and the production of stone-washed jeans. 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 the Three Sisters Wilderness.[28]
Early medicine
Pumice has been used in the medicinal industry for more than 2000 years. Ancient Chinese medicine used ground pumice along with ground mica and 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
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 ancient
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.
Finely ground pumice has been added to some
Cleaning
Pumice stone, sometimes attached to a handle,
Horticulture
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 of carbon dioxide and oxygen to 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 host
Pumice contributes to soil fertility in areas where it is naturally present in the soil due to volcanic activity. For example, in the Jemez Mountains of New Mexico, the Ancestral Puebloans settled on "pumice patches" of the El Cajete Pumice which likely retained a greater amount of moisture and was ideal for farming.[35]
Construction
Pumice is widely used to make lightweight
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
- Pumice raft – Floating mass of pumice in the ocean
References
- ISBN 0-922152-76-4
- ISBN 9780859015226
- ^ Redfern, Simon. "Underwater volcano creates huge floating islands of rock, disrupts shipping". Phys.org. Omicron Technology Ltd. Retrieved 25 April 2014.
- .
- ISBN 978-1-4051-6249-4.
- .
- ^ Crangle, R. Jr. (November 2015). "Mineral resource of the month: Pumice and pumicite". Earth. Retrieved 8 January 2021.
- doi:10.3354/meps086301.1912)
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-Jones
- doi:10.1016/j.epsl.2004.08.009. Archived from the original(PDF) on 2008-07-29. Retrieved 2007-07-14.
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
- ^ "New Island and pumice raft in the Tongas". NASA Earth Observatory. National Aeronautics and Space Administration. 16 November 2006. Retrieved 23 October 2016.
- ISBN 3540127569.
- ^ Gundy, James Van (1 June 2010). "Reticulite". Earth Science Picture of the Day. Universities Space Research Association. Retrieved 5 August 2022.
- ^ "Pumice". Merriam-Webster.com Dictionary. Merriam-Webster. Retrieved 23 February 2022.
- ^ "Spume". Merriam-Webster.com Dictionary. Merriam-Webster. Retrieved 23 February 2022.
- S2CID 129854945.
- ^ a b "What is Pumice?". WorldAtlas. 28 July 2017.
- ^ a b c Crangle, Robert D. Jr. (January 2012). "Pumice and pumicite - USGS Mineral Resources Program" (PDF). United States Geological Survey. Retrieved 25 November 2018.
- ^ a b c "Pumice: Igneous Rock - Pictures, Definition & More". geology.com.
- ^ "Pumice | volcanic glass". Encyclopedia Britannica. 22 November 2023.
- S2CID 127008263.
- ^ "What is Pumice: Origin of Pumice: From Stone to Refined Pumice Powder". hesspumice.com.
- ^ Bolen, Wallace. "Pumice and Pumicite" (PDF).
- ^ Taylor, Alan. "Volcanic Ash and Pumice From Puyehue - The Atlantic". www.theatlantic.com.
- ^ "Havre - the world's largest deep ocean volcanic eruption". Radio New Zealand. 12 June 2018.
- ^ Austin, George S. "Pumice Mining and Environmental Concerns in New Mexico" (PDF).
- S2CID 129854945.
- ^ S2CID 139554392.
- ^ The Oregon Encyclopedia. Michael McCloskey (Sierra Club 2005)
- S2CID 129854945.
- ISBN 9780313331459.
- PMID 9643227.
- S2CID 129854945.
- ^ "Amazon.com: Powerhouse Pumice Toilet Bowl Cleaning Stone with Handle (2-Pack) – Removes Stains, Limescale, Hard Water Rings, Calcium Buildup, Iron and Rust: Home & Kitchen". www.amazon.com. Retrieved 2021-05-15.
- ^ "Improving Soil and other Horticultural Use for Natural Pumice". hesspumice.com. Archived from the original on 2020-03-05. Retrieved 2019-04-04.
- ^ 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. Retrieved 10 January 2021.
- ^ Grasser, Klaus. Building with Pumice (PDF). p. 64. Retrieved 23 March 2019.
External links
- University of Oxford image of pumice. Retrieved 2010-09-27.
- Analytical identification of single source pumice from Greek shores and ancient sites in the Levant
- On the occurrence of a pumice-rich layer in Holocene deposits of western Peloponnesus, Ionian Sea, Greece. A geomorphological and geochemical approach.
- Hess Pumice Archived 2020-03-14 at the Wayback Machine - White papers and technical info of pumice.