Anthodite - Wikipedia, the Free Encyclopedia

Anthodite - Wikipedia, the free encyclopedia

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Anthodite From Wikipedia, the free encyclopedia

Main page Anthodites (Greek, anthos, “flower”, -ode, adjectival Contents combining form, -ite adjectival suffix) are speleothems (cave Featured content formations) composed of long needle-like crystals situated in Current events clusters which radiate outward from a common base. The Random article "needles" may be quill-like or feathery. Most anthodites are Donate to Wikipedia made of the mineral aragonite (a variety of calcium carbonate, Interaction CaCO3), although some are composed of gypsum Help (CaSO4·2H2O). About Wikipedia The term “anthodite” is first cited in the scientific literature in Community portal 1965 by Japanese researcher N. Kashima[1], who described Recent changes “flower-like dripstone” composed of “an alternation of calcite Contact Wikipedia and aragonite”[2][3].

Toolbox Contents [hide] Print/export 1 Structure, composition and appearance Anthodites are featured at the 2 Occurrence commercial Skyline Caverns in Virginia, 3 Types USA 4 Anthodite-like formations 5 References

Structure, composition and appearance [edit]

The individual crystals of anthodites develop in a form described as “acicular” (needle-like) and often branch out as they grow. They usually grow downward from a cave's ceiling. Aragonite crystals are contrasted with those made of calcite (another variety of calcium carbonate) in that the latter tend to be stubby or dog-tooth-like (“rhombohedral”, rather than acicular). Anthodites often have a solid core of aragonite and may have huntite or hydromagnesite deposited near the ends of the branches. Anthodite crystals vary in size from less than a millimeter to about a meter, but are commonly between 1 and 20 millimeters in length.

Occurrence [edit]

Anthodites may occur sporadically throughout some limestone caves, but may be spectacularly abundant in others, with clean white crystals growing all over the calcite or other rock surfaces. Examples of sites with abundant anthodite displays include Carlsbad Caverns in the United States and the Grotte de Moulis in France.

Types [edit]

Among the “quill-like” varieties of anthodite is sometimes included the "sea urchin-like" formation known as flos ferri[4], although others[5] have considered them a slender variety of helictite.

http://en.wikipedia.org/wiki/Anthodite[9/30/2011 3:04:30 AM] Anthodite - Wikipedia, the free encyclopedia

Among the “feathery” varieties of anthodite is "frostwork", a type of speleothem consisting of “bushes” of fine acicular aragonite crystals in radiating clusters. Their appearance is often compared to that of a cactus or thistle plant. In its composite stalagmite form, frostwork may possess spiny limbs like a miniature fir tree. The term was first used by cave guides at Wind Cave in South Dakota, USA, during the 1890s to describe speleothems which looked like ice “frostwork”.

Anthodite-like formations [edit]

Helictites are curved or angular twig-like lateral projections of calcium carbonate, which appear to defy gravity. Rather than radial clusters, helictites often occur in tangled masses. The “twigs” have a tiny central canal. Cave flowers (also known as “gypsum flowers” or “oulopholites”) consist of gypsum or epsomite. In contrast to anthodites, the needles or “petals” of cave flowers grow from the attached end. Cave cotton (also called "gypsum cotton") is very thin, flexible filaments of gypsum or epsomite projecting from a cave wall.

References [edit]

1. ^ Kashima, N. (1965), Mem. Ehime Univ., Sect. 2, Ser. D, 5, 79. 2. ^ Hey, M.H. and P.G. Embrey (1974), “Twenty-eighth List of New Mineral Names” , Mineralogical Magazine, December 1974, Vol. 39, pp 903-932. 3. ^ See also the abstract in Min. Abstr. 18-282. 4. ^ Hill, C. A. and P. Forti, eds (1997), Cave Minerals of the World, 2nd ed., Huntsville, Alabama: National Speleological Society. 5. ^ Shaw, T. (1992), History of Cave Science: The Exploration and Study of Limestone Caves to 1900, 2nd ed., Sydney Speleological Society, Broadway, NSW, Australia.

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Categories: Speleothems

This page was last modified on 29 April 2011 at 10:19.

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http://en.wikipedia.org/wiki/Anthodite[9/30/2011 3:04:30 AM]