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Tufa
TufaTufa belong to a group of crust-like carbonate deposits that are formed through the organically and inorganically controlled precipitation of calcium carbonates from fresh water . Other members of this group are travertines, sinters, and lacustrine limestones or marl lake deposits. Cave deposits of a somewhat similar origin are called flowstones, speleothems (stalagmites and stalactites ). The terms tufa and travertine have a Latin origin. The first is derived from tophus and was used by Pliny to describe porous whitish deposits including volcanic material, which is nowadays called volcanic tuff . The term travertine stems from lapis tiburtinus or Tibur stone. The distinction of terms used to describe surface freshwater carbonates in the literature is not very clear. However, today the term tufa is usually used to describe the more porous varieties, while travertines are denser and sometimes laminated. Sinters are mostly laminated and lack porosity . Lacustrine limestones are hardly compacted. The porosity in tufas is derived from authochtonous plants such as mosses, green algae or reed, which are encrusted by carbonates. Tufas are typically found as deposits of cool spring waters, which are supersaturated by calcium bicarbonate. The precipitation of carbonates in these meteogene deposits is assisted by photosynthesis of phototrophic microbes and plants. Generally, however, any decrease in the partial pressure of CO2 will trigger carbonate precipitation. Travertines, in contrast, are mostly of hydrothermal origin and usually lack fossils of macrophytes or invertebrates. The CO2 in these thermogene deposits can be supplied by various processes including degassing of the upper mantle in areas of tectonic stress. Travertines commonly change to a more porous tufa-fabric in areas where the water has cooled down to near ambient temperature . Tufas and travertines are formed in fluvial environments with a growth rate that can sometimes exceed 0.8 in (2 cm) per year but is seldom smaller than 0.08 in (2 mm) per year. They build up barriers leading to the formation of shallow pools in which carbonate mud is deposited. This succession of barriers and pools can cover wide areas, sometimes miles in length (e.g., Grand Canyon , Arizona or Mammoth Hot Springs, Wyoming). Other seemingly related formations such as the deposits of the geysers and hot springs in the Yellowstone National Park (Wyoming) are in fact siliceous sinter. Tufas and travertines are particularly common in the late Pleistocene. Today, they form under a wide variety of climatic regimes from cool and temperate to semi-arid conditions while the growth of fossil travertines of the Quaternary seems to be restricted to the interstadials and interglacials in high and medium latitudes. Some calcareous fresh water deposits show well-developed laminae that probably mirror seasonal differences in one or more environmental variables (water depth or temperature, detrital input). See also Stalactites and stalagmites |
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"Tufa." World of Earth Science. 2003. Encyclopedia.com. 11 Feb. 2012 <http://www.encyclopedia.com>. "Tufa." World of Earth Science. 2003. Encyclopedia.com. (February 11, 2012). http://www.encyclopedia.com/doc/1G2-3437800624.html "Tufa." World of Earth Science. 2003. Retrieved February 11, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1G2-3437800624.html |
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tufa
tu·fa / ˈt(y)oōfə/ • n. a porous rock composed of calcium carbonate and formed by precipitation from water, e.g., around mineral springs. ∎ another term for tuff. DERIVATIVES: tu·fa·ceous / t(y)oōˈfāshəs/ adj. |
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"tufa." The Oxford Pocket Dictionary of Current English. 2009. Encyclopedia.com. 11 Feb. 2012 <http://www.encyclopedia.com>. "tufa." The Oxford Pocket Dictionary of Current English. 2009. Encyclopedia.com. (February 11, 2012). http://www.encyclopedia.com/doc/1O999-tufa.html "tufa." The Oxford Pocket Dictionary of Current English. 2009. Retrieved February 11, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O999-tufa.html |
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tufa
tufa. Soft porous rock formed from the deposits of springs rich in lime. It is easily sawn and worked, but durable, hardening on exposure to air, and has been used since ancient times for buildings and sometimes for sculpture (in particular, the Romans used it for carved sarcophagi).
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IAN CHILVERS. "tufa." The Oxford Dictionary of Art. 2004. Encyclopedia.com. 11 Feb. 2012 <http://www.encyclopedia.com>. IAN CHILVERS. "tufa." The Oxford Dictionary of Art. 2004. Encyclopedia.com. (February 11, 2012). http://www.encyclopedia.com/doc/1O2-tufa.html IAN CHILVERS. "tufa." The Oxford Dictionary of Art. 2004. Retrieved February 11, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O2-tufa.html |
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tufa
tufa (calc-tufa) Sedimentary rock formed by the deposition or precipitation of calcium carbonate, or more rarely silica, as a thin layer around saline springs, or by the encrustations on stalactites and stalagmites. See also TRAVERTINE.
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AILSA ALLABY and MICHAEL ALLABY. "tufa." A Dictionary of Earth Sciences. 1999. Encyclopedia.com. 11 Feb. 2012 <http://www.encyclopedia.com>. AILSA ALLABY and MICHAEL ALLABY. "tufa." A Dictionary of Earth Sciences. 1999. Encyclopedia.com. (February 11, 2012). http://www.encyclopedia.com/doc/1O13-tufa.html AILSA ALLABY and MICHAEL ALLABY. "tufa." A Dictionary of Earth Sciences. 1999. Retrieved February 11, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O13-tufa.html |
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tufa
tufa(calc-tufa) A sedimentary rock formed by the deposition or precipitation of calcium carbonate, or more rarely silica, as a thin layer around saline springs, or by the encrustations on stalactites and stalagmites.
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MICHAEL ALLABY. "tufa." A Dictionary of Ecology. 2004. Encyclopedia.com. 11 Feb. 2012 <http://www.encyclopedia.com>. MICHAEL ALLABY. "tufa." A Dictionary of Ecology. 2004. Encyclopedia.com. (February 11, 2012). http://www.encyclopedia.com/doc/1O14-tufa.html MICHAEL ALLABY. "tufa." A Dictionary of Ecology. 2004. Retrieved February 11, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O14-tufa.html |
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tufa
tufa (geol.) porous stone. XVIII. — †It. tufa, local var. of tufo — late L. tōfus, tōphus.
So tuff XVI. — F. tuf(f)e, tuf — It. tufo. |
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T. F. HOAD. "tufa." The Concise Oxford Dictionary of English Etymology. 1996. Encyclopedia.com. 11 Feb. 2012 <http://www.encyclopedia.com>. T. F. HOAD. "tufa." The Concise Oxford Dictionary of English Etymology. 1996. Encyclopedia.com. (February 11, 2012). http://www.encyclopedia.com/doc/1O27-tufa.html T. F. HOAD. "tufa." The Concise Oxford Dictionary of English Etymology. 1996. Retrieved February 11, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O27-tufa.html |
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tufa
tufa. Rough, porous stone, such as that from which the Roman catacombs are cut.
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JAMES STEVENS CURL. "tufa." A Dictionary of Architecture and Landscape Architecture. 2000. Encyclopedia.com. 11 Feb. 2012 <http://www.encyclopedia.com>. JAMES STEVENS CURL. "tufa." A Dictionary of Architecture and Landscape Architecture. 2000. Encyclopedia.com. (February 11, 2012). http://www.encyclopedia.com/doc/1O1-tufa.html JAMES STEVENS CURL. "tufa." A Dictionary of Architecture and Landscape Architecture. 2000. Retrieved February 11, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O1-tufa.html |
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tufa
tufa see travertine . |
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"tufa." The Columbia Encyclopedia, 6th ed.. 2008. Encyclopedia.com. 11 Feb. 2012 <http://www.encyclopedia.com>. "tufa." The Columbia Encyclopedia, 6th ed.. 2008. Encyclopedia.com. (February 11, 2012). http://www.encyclopedia.com/doc/1E1-X-tufa.html "tufa." The Columbia Encyclopedia, 6th ed.. 2008. Retrieved February 11, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1E1-X-tufa.html |
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tufa
tufa see travertine, tufa
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PAUL HANCOCK and BRIAN J. SKINNER. "tufa." The Oxford Companion to the Earth. 2000. Encyclopedia.com. 11 Feb. 2012 <http://www.encyclopedia.com>. PAUL HANCOCK and BRIAN J. SKINNER. "tufa." The Oxford Companion to the Earth. 2000. Encyclopedia.com. (February 11, 2012). http://www.encyclopedia.com/doc/1O112-tufa.html PAUL HANCOCK and BRIAN J. SKINNER. "tufa." The Oxford Companion to the Earth. 2000. Retrieved February 11, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O112-tufa.html |
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tufa
tufa
•chaffer, gaffer, Jaffa, kafir, Staffa
•alfalfa, alpha, Balfour, Wadi Halfa
•camphor, chamfer
•Luftwaffe
•laugher, staffer
•heifer, zephyr
•chafer, trefa, wafer
•cockchafer
•feoffor, reefer
•differ, sniffer
•pilfer • titfer • umbellifer • Jennifer
•conifer • apocrypha • thurifer
•crucifer, Lucifer
•Potiphar • aquifer
•cipher, encipher, fifer, Haifa, knifer, lifer
•coffer, cougher, Offa, offer, proffer, quaffer, scoffer
•golfer • phosphor • Forfar • Altdorfer
•chauffeur, gofer, goffer, gopher, loafer, Nuku'alofa, Ophir, shofar, sofa
•Fraunhofer
•hoofer, loofah, opera buffa, roofer, spoofer, tufa, woofer
•waterproofer
•bluffer, buffer, duffer, puffer, snuffer, suffer
•sulphur (US sulfur) • telegrapher
•calligrapher, serigrapher
•autobiographer, bibliographer, biographer, cartographer, choreographer, cinematographer, crystallographer, geographer, Hagiographa, hagiographer, iconographer, lexicographer, lithographer, oceanographer, palaeographer (US paleographer), photographer, pornographer, radiographer, stenographer, topographer, typographer
•philosopher, theosopher
•metaphor • Christopher • surfer
•Bonhoeffer • windsurfer
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"tufa." Oxford Dictionary of Rhymes. 2007. Encyclopedia.com. 11 Feb. 2012 <http://www.encyclopedia.com>. "tufa." Oxford Dictionary of Rhymes. 2007. Encyclopedia.com. (February 11, 2012). http://www.encyclopedia.com/doc/1O233-tufa.html "tufa." Oxford Dictionary of Rhymes. 2007. Retrieved February 11, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O233-tufa.html |
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