Moonmilk

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Moonmilk ostensibly created from Macromonas bipunctata in the cave Bergmilchkammer Bergmilchkammer 04.jpg
Moonmilk ostensibly created from Macromonas bipunctata in the cave Bergmilchkammer
Diagram of dripstone cave structures (moonmilk is labelled I) Tropfsteine.svg
Diagram of dripstone cave structures (moonmilk is labelled I)

Moonmilk (sometimes called mondmilch, also known as montmilch or as cave milk) is a white, creamy substance found inside limestone, dolomite, and possibly other types of caves. It is a precipitate from limestone comprising aggregates of fine crystals of varying composition usually made of carbonates such as calcite, aragonite, hydromagnesite, and/or monohydrocalcite.

There are several hypotheses concerning the origin of moonmilk. One of these explains moonmilk to be the result of bacterial action rather than from chemical reactions. According to this particular hypothesis, moonmilk is thought to have been created by the bacterium Macromonas bipunctata . However, no microbiological studies have been carried out so far. Moonmilk was originally explained as created by moon rays. [1]

It is possible that moonmilk is formed by water that dissolves and softens the karst of caves consisting of carbonates, and carries dissolved nutrients that can be used by microbes, such as Actinomycetes. As the microbial colonies grow, they trap and accumulate chemically precipitated crystals in the organic matter-rich matrix formed that way. It has been suggested that these heterotrophic microbes, which produce CO2 as a waste product of respiration and possibly organic acids, may help to dissolve the carbonate.[ citation needed ]

In 2017, archæologists at the University of Chinese Academy of Sciences in China discovered a bronze jar dating to over 2,700 years ago containing animal fat combined with moonmilk, believed to have been a cosmetic face cream used by Chinese noblemen. [2]

Being soft, moonmilk was frequently the medium for finger fluting, a form of prehistoric art.

The world's largest formation of brushite moonmilk is found in the Big Room of Kartchner Caverns State Park in southern Arizona. [3]

In the middle of 16th century moonmilk was used as a medicine according to Gessner, and continued to be used as such until the 19th century. It is said to have cured acidosis and probably cardialgia by neutralizing an overdose of acid. It had no adverse health effects. [4]

Scanning electron microscope (SEM) image of moonmilk, showing fibrous calcite (calcium carbonate) strands approximately 0.83mm (0.00083 millimetres) thick. Moonmilk image viewed with Scanning Electron Microscope.jpg
Scanning electron microscope (SEM) image of moonmilk, showing fibrous calcite (calcium carbonate) strands approximately 0.83μm (0.00083 millimetres) thick.

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<span class="mw-page-title-main">Cave</span> Natural underground space large enough for a human to enter

A cave or cavern is a natural void in the ground, specifically a space large enough for a human to enter. Caves often form by the weathering of rock and often extend deep underground. The word cave can refer to smaller openings such as sea caves, rock shelters, and grottos, that extend a relatively short distance into the rock and they are called exogene caves. Caves which extend further underground than the opening is wide are called endogene caves.

<span class="mw-page-title-main">Karst</span> Topography from dissolved soluble rocks

Karst is a topography formed from the dissolution of soluble carbonate rocks such as limestone, dolomite, and gypsum. It is characterized by features like poljes above and drainage systems with sinkholes and caves underground. It has also been documented for more weathering-resistant rocks, such as quartzite, given the right conditions. Subterranean drainage may limit surface water, with few to no rivers or lakes. In regions where the dissolved bedrock is covered or confined by one or more superimposed non-soluble rock strata, distinctive karst features may occur only at subsurface levels and can be totally missing above ground.

<span class="mw-page-title-main">Limestone</span> Sedimentary rocks made of calcium carbonate

Limestone is a type of carbonate sedimentary rock which is the main source of the material lime. It is composed mostly of the minerals calcite and aragonite, which are different crystal forms of CaCO3. Limestone forms when these minerals precipitate out of water containing dissolved calcium. This can take place through both biological and nonbiological processes, though biological processes, such as the accumulation of corals and shells in the sea, have likely been more important for the last 540 million years. Limestone often contains fossils which provide scientists with information on ancient environments and on the evolution of life.

<span class="mw-page-title-main">Stalactite</span> Elongated mineral formation hanging down from a cave ceiling

A stalactite is a mineral formation that hangs from the ceiling of caves, hot springs, or man-made structures such as bridges and mines. Any material that is soluble and that can be deposited as a colloid, or is in suspension, or is capable of being melted, may form a stalactite. Stalactites may be composed of lava, minerals, mud, peat, pitch, sand, sinter, and amberat. A stalactite is not necessarily a speleothem, though speleothems are the most common form of stalactite because of the abundance of limestone caves.

<span class="mw-page-title-main">Calcite</span> Calcium carbonate mineral

Calcite is a carbonate mineral and the most stable polymorph of calcium carbonate (CaCO3). It is a very common mineral, particularly as a component of limestone. Calcite defines hardness 3 on the Mohs scale of mineral hardness, based on scratch hardness comparison. Large calcite crystals are used in optical equipment, and limestone composed mostly of calcite has numerous uses.

<span class="mw-page-title-main">Calcium carbonate</span> Chemical compound

Calcium carbonate is a chemical compound with the chemical formula CaCO3. It is a common substance found in rocks as the minerals calcite and aragonite, most notably in chalk and limestone, eggshells, gastropod shells, shellfish skeletons and pearls. Materials containing much calcium carbonate or resembling it are described as calcareous. Calcium carbonate is the active ingredient in agricultural lime and is created when calcium ions in hard water react with carbonate ions to create limescale. It has medical use as a calcium supplement or as an antacid, but excessive consumption can be hazardous and cause hypercalcemia and digestive issues.

<span class="mw-page-title-main">Sodium carbonate</span> Chemical compound

Sodium carbonate is the inorganic compound with the formula Na2CO3 and its various hydrates. All forms are white, odourless, water-soluble salts that yield alkaline solutions in water. Historically, it was extracted from the ashes of plants grown in sodium-rich soils. Because the ashes of these sodium-rich plants were noticeably different from ashes of wood, sodium carbonate became known as "soda ash". It is produced in large quantities from sodium chloride and limestone by the Solvay process, as well as by carbonating sodium hydroxide which is made using the Chlor-alkali process.

<span class="mw-page-title-main">Stalagmite</span> Elongate mineral formation found on a cave floor

A stalagmite is a type of rock formation that rises from the floor of a cave due to the accumulation of material deposited on the floor from ceiling drippings. Stalagmites are typically composed of calcium carbonate, but may consist of lava, mud, peat, pitch, sand, sinter, and amberat.

<span class="mw-page-title-main">Speleothem</span> Structure formed in a cave by the deposition of minerals from water

A speleothem is a geological formation by mineral deposits that accumulate over time in natural caves. Speleothems most commonly form in calcareous caves due to carbonate dissolution reactions. They can take a variety of forms, depending on their depositional history and environment. Their chemical composition, gradual growth, and preservation in caves make them useful paleoclimatic proxies.

<span class="mw-page-title-main">Dolomite (rock)</span> Sedimentary carbonate rock that contains a high percentage of the mineral dolomite

Dolomite (also known as dolomite rock, dolostone or dolomitic rock) is a sedimentary carbonate rock that contains a high percentage of the mineral dolomite, CaMg(CO3)2. It occurs widely, often in association with limestone and evaporites, though it is less abundant than limestone and rare in Cenozoic rock beds (beds less than about 66 million years in age). The first geologist to distinguish dolomite rock from limestone was Belsazar Hacquet in 1778.

<span class="mw-page-title-main">Treak Cliff Cavern</span> Show cave in Derbyshire, England

Treak Cliff Cavern is a show cave near Castleton in Derbyshire, England. It is part of the Castleton Site of Special Scientific Interest and one of only two sites where the ornamental mineral Blue John is still excavated. As part of an agreement with English Nature, the Blue John that can be seen in the show cave is not mined but it is extracted in small quantities from other areas of the cave and made into saleable items like bowls, jewellery, and ornaments.

<span class="mw-page-title-main">Caproic acid</span> Chemical compound

Caproic acid, also known as hexanoic acid, is the carboxylic acid derived from hexane with the chemical formula CH3(CH2)4COOH. It is a colorless oily liquid with an odor that is fatty, cheesy, waxy, and like that of goats or other barnyard animals. It is a fatty acid found naturally in various animal fats and oils, and is one of the chemicals that gives the decomposing fleshy seed coat of the ginkgo its characteristic unpleasant odor. It is also one of the components of vanilla and cheese. The primary use of caproic acid is in the manufacture of its esters for use as artificial flavors, and in the manufacture of hexyl derivatives, such as hexylphenols. Salts and esters of caproic acid are known as caproates or hexanoates. Several progestin medications are caproate esters, such as hydroxyprogesterone caproate and gestonorone caproate.

<span class="mw-page-title-main">Solutional cave</span> Type of cave

A solutional cave, solution cave, or karst cave is a cave usually formed in the soluble rock limestone. It is the most frequently occurring type of cave. It can also form in other rocks, including chalk, dolomite, marble, salt beds, and gypsum.

<span class="mw-page-title-main">Calcite rafts</span> Cave-crystallized calcite crusts

Calcite crystals form on the surface of quiescent bodies of water, even when the bulk water is not supersaturated with respect to calcium carbonate. The crystals grow, attach to one other and appear to be floating rafts of a white, opaque material. The floating materials have been referred to as calcite rafts or "leopard spots".

<span class="mw-page-title-main">Indiana Caverns</span>

Indiana Caverns is part of the Binkley Cave system near Corydon, Indiana.

<i>Macromonas bipunctata</i> Species of bacterium

Macromonasbipunctata is a Gram-negative, colorless, and heterotrophic sulfur bacterium of the genus Macromonas. It is commonly found in sewage aeration tanks and caves where moonmilk has formed. In the 1920s, researcher Gicklhorn first discovered this organism under the name Pseudomonasbipunctata. After further study and culturing by Utermöhl and Koppe, in 1923, it was later renamed Macromonasbipunctata. This organism is thought to be non-pathogenic species. In fact, the moonmilk produced was referenced as a remedy for infections in the Middle Ages.

<span class="mw-page-title-main">Calthemite</span> Secondary calcium carbonate deposit growing under man-made structures

Calthemite is a secondary deposit, derived from concrete, lime, mortar or other calcareous material outside the cave environment. Calthemites grow on or under, man-made structures and mimic the shapes and forms of cave speleothems, such as stalactites, stalagmites, flowstone etc. Calthemite is derived from the Latin calx "lime" + Latin < Greek théma, "deposit" meaning ‘something laid down’, and the Latin –ita < Greek -itēs – used as a suffix indicating a mineral or rock. The term "speleothem", due to its definition can only be used to describe secondary deposits in caves and does not include secondary deposits outside the cave environment.

Diamond Caverns in Park City, Kentucky was discovered on July 14, 1859. Tours are available year around; closed Thanksgiving, Christmas Eve, and Christmas. Tours last one hour and is a half mile round trip.

<span class="mw-page-title-main">Hells Bells (cave formations)</span> Underwater cave formation

Hells Bells are hollow bell- or cone-shaped structures of carbonate that can reach lengths of 2 metres. They are found underwater in El Zapote cenote in Quintana Roo, Mexico, on the Yucatan Peninsula; similar formations exist in other caves. In a certain depth range, such structures cover the entire surface of the cave including submerged tree trunks and other Hells Bells, although they never touch each other.

<span class="mw-page-title-main">Silicification</span> Geological petrification process

In geology, silicification is a petrification process in which silica-rich fluids seep into the voids of Earth materials, e.g., rocks, wood, bones, shells, and replace the original materials with silica (SiO2). Silica is a naturally existing and abundant compound found in organic and inorganic materials, including Earth's crust and mantle. There are a variety of silicification mechanisms. In silicification of wood, silica permeates into and occupies cracks and voids in wood such as vessels and cell walls. The original organic matter is retained throughout the process and will gradually decay through time. In the silicification of carbonates, silica replaces carbonates by the same volume. Replacement is accomplished through the dissolution of original rock minerals and the precipitation of silica. This leads to a removal of original materials out of the system. Depending on the structures and composition of the original rock, silica might replace only specific mineral components of the rock. Silicic acid (H4SiO4) in the silica-enriched fluids forms lenticular, nodular, fibrous, or aggregated quartz, opal, or chalcedony that grows within the rock. Silicification happens when rocks or organic materials are in contact with silica-rich surface water, buried under sediments and susceptible to groundwater flow, or buried under volcanic ashes. Silicification is often associated with hydrothermal processes. Temperature for silicification ranges in various conditions: in burial or surface water conditions, temperature for silicification can be around 25°−50°; whereas temperatures for siliceous fluid inclusions can be up to 150°−190°. Silicification could occur during a syn-depositional or a post-depositional stage, commonly along layers marking changes in sedimentation such as unconformities or bedding planes.

References

  1. Gessner, Conrad (1555). Descriptio Montis Fracti sive Montis Pilati [Description of Mount Fractus, or Mount Pilatus] (in Latin). p. 54. Retrieved March 12, 2016.
  2. Marshall, Michael (2019-02-26). "2700-year-old face cream was made from animal fat and cave 'milk'". New Scientist. Retrieved 2021-02-08.
  3. Cronkite, Amy. "State celebrates 10 years of Kartchner Caverns Big Room tours" . Retrieved 27 February 2015.
  4. Moonmilk Archived 2012-05-31 at the Wayback Machine in showcaves.com.