Infobox mineral name Aragonite category Carbonate mineral boxwidth boxbgcolor image Aragonite Salsigne France.jpg imagesize caption Aragonite from Salsignes Mine, Aude department, France Size 30x30x20 ... ref ref name Webmin http webmineral.com data Aragonite.shtml Webmineral data ref Aragonite is a carbonate ... environments. Aragonite s crystal lattice differs from that of calcite, resulting in a different ... results in pseudo hexagonal forms. Aragonite may be columnar or fibrous, occasionally in branching ... for aragonite is Molina de Arag n Guadalajara province Guadalajara , Spain , 25 km from Aragon for which it was named in 1797. ref name Mindat An aragonite cave, the Ochtinsk Aragonite Cave , is situated in Slovakia . In the USA, aragonite in the form of stalactite s and cave flowers anthodite is known from Carlsbad Caverns and other caves. Massive deposits of oolitic aragonite sand are found on the seabed in the Bahamas . Aragonite forms naturally in almost all mollusk shells, and as the calcareous ... different from those of inorganic aragonite. In some mollusks, the entire shell is aragonite in others, aragonite forms only discrete parts of a bimineralic shell aragonite plus calcite . Aragonite also .... The nacreous layer of the aragonite fossil shells of some extinct ammonite s forms an iridescent material called ammolite . Ammolite is primarily aragonite with impurities that make it iridescent and valuable as a gemstone . Aragonite is metastable and is thus commonly replaced by calcite in fossils. Aragonite older than the Carboniferous is essentially unknown. ref cite doi 10.1080 03115518508618971 ref Physical properties Aragonite is thermodynamics thermodynamically unstable at standard ... readily than aragonite. Gallery gallery widths 200px heights 200px perrow 3 Image Aragonite 2 Enguidanos.jpg Aragonite crystals from Cuenca, Castile La Mancha, Spain File Aragonite 232887.jpg Cluster of twinned aragonite from Morocco Image BaculitesSuturesAragonite.jpg Remnant biogenic aragonite ... more details
Image CalciteAragonite.jpg thumb right The alternation of calcite and aragonite seas through geologic time . An aragonite sea contains aragonite and high magnesium calcite as the primary inorganic carbonate precipitates. Therefore, the chemical conditions of the seawater must be notably high in magnesium content for an aragonite sea to form. This is in contrast to a calcite sea in which low magnesium calcite is the primary inorganic marine calcium carbonate precipitate. The Early Paleozoic and the Middle to Late Mesozoic oceans were predominantly calcite seas, whereas the Middle Paleozoic through the Early Mesozoic and the Cenozoic including today are characterized by aragonite seas. ref harvnb Wilkinson Owen Carroll 1985 ref ref harvnb Wilkinson Given 1986 ref ref harvnb Morse Mackenzie 1990 ref ref harvnb Lowenstein Timofeeff Brennan Hardie 2001 ref ref harvnb Palmer Wilson 2004 ref Aragonite seas form due to several factors, the most obvious of these is a high magnesium content. However, the sea level and the temperature of the surrounding system also determine whether an aragonite sea will form. ref harvnb Adabi 2004 ref Aragonite is the predominant mineral in warm, shallow marine environments. Calcite on the other hand, is the dominant mineral in cool marine water environments. This trend has been observed by looking at the chemistry of carbonates, dating them and analyzing the conditions under which they were formed. One study has examined the temporal and spatial distribution ... similar to today s seas which favor aragonite production. ref harvnb Westphall Munnecke 2003 ref Citations ... as evidence of large scale, early skeletal aragonite dissolution in a Silurian Sea journal Geology ... author Mohammad, A. year 2004 title A re evaluation of aragonite versus calcite seas journal Carbonates ... and dissolution of biogenic aragonite in shallow Ordovician calcite seas journal Lethaia volume ... title Palaeoecological evidence for early aragonite dissolution in ancient calcite seas journal Nature ... more details
Unreferenced date June 2008 Image Ochtina Aragonite Cave 38.jpg thumb White aragonite forms the cave s rare decoration Image Ochtina Aragonite Cave 28.jpg thumb Aragonite inside the cave Ochtinsk Aragonite Cave lang sk Ochtinsk aragonitov jasky a , lang hu Martonh zi aragonitbarlang Citation needed date August 2008 the Magyar wikipedia article uses a different title is a unique aragonite cave situated in southern Slovakia , near Ro ava . Although only 300 m long, it is famous for its rare aragonite filling. There are only three aragonite caves discovered in the world so far. In the so called Milky Way Hall, the main attraction of the cave, white branches and clusters of aragonite shine like stars in the Milky Way . The cave was discovered by chance by Jan Bystricky in 1954 and opened to the public in 1972. Along with other caves of the Slovak Karst , it is included in the UNESCO World Heritage list as a component of Caves of Aggtelek Karst and Slovak Karst site. See also List of caves in Slovakia External links commonscat Ochtina Aragonite Cave http www.sacr.sk article?id 14&category 9&lang en Short overview for tourists http www.ssj.sk jaskyne spristupnene ochtinska aragonitova Official site with pictures, map of the cave, and contact information World Heritage Sites in Slovakia coord 48 39 49.12 N 20 18 20.35 E dim 200 scale 2000 region SK type landmark source dewiki display title Category Caves of Slovakia Category World Heritage Sites in Slovakia Slovakia geo stub be be x old cs Ochtinsk aragonitov jeskyn de Ochtinsk aragonitov jasky a hu Martonh zi aragonitbarlang pl Ochti ska Jaskinia Aragonitowa ru sk Ochtinsk aragonitov jasky a ... more details
Oolitic aragonite sand forms in tropical waters. Most of the topography of the Bahama Banks is composed of calcium carbonate Oolite oolitic aragonite sand material. The natural formation through Precipitation chemistry precipitation and sedimentation of aragonite sand in the Bahamas surpasses anyplace else in the world. Fact date June 2009 There are billions of tons of this type of sand material in reserve and millions of tons more created annually. Fact date June 2009 Commercial uses Commercial uses are similar to limestone and other high calcium carbonate materials. References http coralreefwatch.noaa.gov satellite oa description oaps intro aragonite ss.html An Introduction to Ocean Acidification See also List of types of limestone Category Sediments ocean stub ... more details
Infobox mineral name Vaterite boxwidth boxbgcolor image Vaterite sea12c.jpg imagesize alt caption Vaterite category Carbonate minerals formula CaCO sub 3 sub strunz 05.AB.20 dana symmetry unit cell molweight color colour habit system twinning cleavage fracture tenacity mohs luster streak diaphaneity gravity density polish opticalprop refractive birefringence pleochroism 2V dispersion extinction length fast slow fluorescence absorption melt fusibility diagnostic solubility impurities alteration other prop1 prop1text references Vaterite calcium Ca carbon C oxygen O sub 3 sub is a mineral, a polymorphism materials science polymorph of calcium carbonate . It was named after the German mineralogist Heinrich Vater. It is also known as mu calcium carbonate &mu CaCO sub 3 sub and has a JCPDS number of 13 192. Vaterite, like aragonite, is a metastable phase of calcium carbonate at ambient conditions at the surface of the earth. As it is less stable than either calcite or aragonite, vaterite has a higher solubility than either of these phases. Therefore, once vaterite is exposed to water , it converts to calcite at low temperature or aragonite at high temperature 60 C . However, vaterite does occur naturally in mineral spring s, organic tissue, gallstone s, and urinary calculi. In those circumstances, some impurities metal ions or organic matter may stabilize the vaterite and prevent its transformation into calcite or aragonite . Vaterite is usually colorless, its shape is spherical, and its diameter is small, ranging from 0.05 to 5 &mu m. Vaterite can be produced as the first mineral deposits repairing natural or experimentally induced shell damage in some aragonite shelled molluscs e.g., gastropods . Subsequent shell deposition occurs as aragonite. Vaterite belongs to the hexagonal crystal system , whereas calcite is trigonal and aragonite is orthorhombic . See also Monohydrocalcite Monohydrocalcite, CaCO sub 3 sub H sub 2 sub O Ikaite Ikaite, CaCO sub 3 sub 6H sub 2 sub O ... more details
Hermatypic corals or stony corals are reef building coral s, while corals that do not deposit aragonite structures and contribute to coral reef development are referred to as ahermatypic non reef building species. ref cite journal author Schuhmacher H, Zibrowius H title What is hermatypic? journal Coral Reefs volume issue pages 1 9 year 2006 doi 10.1007 BF00302198 ref References reflist invertebrate stub corals Category Cnidarians Category Coral reefs zh ... more details
in the world. Although Ochtina Aragonite Cave is just 300 m long with a tourist circuit not longer than 230 m, it is famous for its rare aragonite filling since there are only three aragonite caves ..., white branches and clusters of aragonite shine like stars in the Milky Way. The cave was discovered ... 2 by andy205.jpg Baradla Cave Image Okt 15.jpg Baradla Cave Image Ochtina Aragonite Cave 54.jpg Ochtina Aragonite Cave Image Ochtina Aragonite Cave 29.jpg Ochtina Aragonite Cave Image Ochtina Aragonite Cave 12.jpg Ochtina Aragonite Cave Image Ochtina Aragonite Cave 38.jpg Detail of the aragonite decoration Image Ochtina Aragonite Cave 22.jpg Detail of the aragonite decoration Image Jaskinia Gombasecka ... more details
orphan date January 2010 Coleolids are Cambrian Small shelly fossils with an aragonite skeleton. ref name Porter cite doi 10.1126 science.1137284 ref Their affinity is unknown but they were probably produced by an organism of the annelid grade of complexity. ref name BriggsCrowther cite book title Palaeobiology II By Derek E. G. Briggs, Peter R. Crowther ref rp 37 References reflist Category Cambrian animals Category Prehistoric life paleo stub ... more details
Image CalciteAragonite.jpg thumb right The alternation of calcite and aragonite seas through geologic time . A calcite sea is one in which low magnesium calcite is the primary inorganic marine calcium carbonate precipitate. An aragonite sea is the alternate seawater chemistry in which aragonite and high magnesium calcite are the primary inorganic carbonate precipitates. The Early Paleozoic and the Middle to Late Mesozoic oceans were predominantly calcite seas, whereas the Middle Paleozoic through the Early Mesozoic and the Cenozoic including today are characterized by aragonite seas Wilkinson et al., 1985 Wilkinson and Given, 1986 Morse and Mackenzie, 1990 Lowenstein et al., 2001 Palmer and Wilson, 2004 . Image CarmelHdgd.jpg thumb left Jurassic hardground with encrusting oysters and borings. The most significant geological and biological effects of calcite sea conditions include rapid and widespread ... , and the contemporaneous dissolution of aragonite shells in shallow warm seas Cherns and Wright ... and Jurassic , but virtually absent from the aragonite seas of the Permian Palmer, 1982 ... infaunal and or had thick periostraca Pojeta, 1971 , or had an inner shell of aragonite and an outer shell of calcite Harper et al., 1997 . This was apparently because aragonite dissolved quickly on the seafloor ... in the Mg Ca ratio favors the precipitation of calcite over aragonite. Increased seafloor ... et al., 2001 . gallery Image CalciteSeasTable.jpg Table showing the conditions for calcite and aragonite ... of the original aragonite shell and calcitic cementation of the mold. Image NautiloidInternalExternal.jpg ... aragonite shell and calcitic cementation. Image Paleosabella4CS.jpg The boring Palaeosabella ... Missing molluscs as evidence of large scale, early skeletal aragonite dissolution in a Silurian ... precipitation and dissolution of biogenic aragonite in shallow Ordovician calcite seas journal ... evidence for early aragonite dissolution in ancient calcite seas journal Nature volume 335 issue ... more details
and ancient rocks, indicating the removal of a soluble polymorph usually aragonite . Variation ... of growth by accretion like a snowball from the polymineralic sediment of fine aragonite, high magnesium calcite HMC and low magnesium calcite LMC , must explain how only aragonite needles ... more details
Image Jewel Cave 3.jpg thumb upright 1.75 alt frostwork Frostwork in Jewel Cave, South Dakota. Frostwork is a type of speleothem cave formation composed of acicular needle like growths almost always composed of aragonite a Polymorphism materials science polymorph of calcite or calcite replaced by aragonite ref Hill, C. and Forti, P. 1997 , Cave Minerals of the World , National Speleological Society , 2nd Edition. ref . It is a variety of anthodite . In some caves frostwork may grow on top of cave popcorn or boxwork . Formation The origin of frostwork is somewhat controversial. Formation of cave frostwork has been attributed to moist, circulating air which, containing dissolved calcium carbonate , drifted against rock surfaces and coated them with the delicate crystals. Frostwork has also been attributed to water seepage from cave passageways in which there are relatively high evaporation rates. Occurrence Notable frostwork deposits are found in a number of cave s in the Black Hills region of South Dakota , USA , most notable in Wind Cave National Park and Jewel Cave National Monument . Perhaps the most extensive displays known are found in Lechuguilla Cave , New Mexico. References references External links http www.nps.gov archive wica Speleothems.htm Wind Cave National Park Speleothems http www.goodearthgraphics.com virtcave aragonit aragonit.html The Virtual Cave s page on aragonite and frostwork Category Speleothems geology stub ... more details
Image OoidSurface01.jpg thumb right 250px Ooids on the surface of a limestone Carmel Formation Middle Jurassic of southern Utah, USA. Largest is 1.0 mm in diameter. Allochem is a term introduced by Folk 1959 to describe the recognisable grains in carbonate rocks . Any fragment from around mm upwards in size may be considered an allochem. Examples would include ooids , peloids , oncolite s, fossil or pre existing carbonate fragments. Fragments are still termed allochems if they have undergone chemical transformations for example if an aragonite shell were to dissolve and be later replaced by calcite , the replacement would still be deemed an allochem. The allochems are typically embedded in a Matrix geology matrix of micrite lime mud or sparry calcite. References Folk, R.L., 1959, Practical petrographic classification of limestones American Association of Petroleum Geologists Bulletin, v. 43, p. 1 38. Category Sedimentology geology stub ... more details
Unreferenced date November 2006 Taxobox name Linguliformea regnum Animal ia phylum Brachiopod a subphylum Linguliformea subdivision ranks Classes subdivision Lingulata br Paterinata Linguliformea is a subphylum of inarticulate brachiopod s. These were the earliest of brachiopods, ranging from the Cambrian into the Holocene . They rapidly diversified during the Cambrian into the Ordovician , but most families went extinct by the end of the Devonian . The articulation in these brachiopods is lacking. These brachiopods have adductor and oblique muscles, but no diductor muscles. The anus is located at the side of the body. The pedicle is a hollow extension of the ventral body wall. Posterior body wall separates dorsal and ventral mantles. The shells are usually made up of apatite calcium phosphate , however rare cases have calcite or aragonite shells. Category Brachiopods Brachiopod stub ... more details
italic title Unreferenced date March 2007 Taxobox name Acanthoplites status fossil fossil range regnum Animal ia phylum Mollusc a classis Cephalopod a subclassis Ammonoidea genus Acanthoplites genus authority subdivision ranks subdivision Acanthoplites is an extinct genus of cephalopod belonging to the Ammonite subclass. Like many other Ammonites, Acanthoplites was a marine nektonic carnivore. Fossil Record The most commonly preserved remains of Acanthoplites are the animals shells, which were composed of Aragonite . This animal first appears in rocks dating to the late Aptian portion of the Cretaceous Period. This means that Acanthoplites fossils are 112 125 million years old. No fossils of Acanthoplites have been found post dating the Aptian. Remains from this genus have been found on multiple continents in the nations of Mexico , Argentina , Morocco and South Africa Species A. aegis A. barryana A. crassicostatus A. gardneri A. gragasensis A. perrini A. spathi A. seunesi A. uhligi Category Ammonitida eu Acanthoplites pl Acanthoplites ... more details
orphan date December 2007 Neomorphism is a recrystallization geology recrystallization process in sedimentary rock s that changes the size either larger or smaller and form it can include the overgrowth of polymorph ous minerals of crystals in the rock. The chemical composition of the rock remains the same. Neomorphism thus destroys the original crystals and builds new crystals that grow over the older ones. In limestone carbonate rocks neomorphism is an important step in the diagenesis of such rocks, in which the micrite micritic matrix geology matrix is exchanged for microspar s bigger, loaf shaped crystals . The process also reduces the amount of under surface conditions instable aragonite and magnesium rich calcite in the rock by replacing them with normal calcite. The name neomorphism was minted by Folk in 1965. ref Folk, R.L. 1965 Some aspects of recrystallization in ancient limestones , Society of Economic Paleontologists and Mineralogists, spec. pub. 13 , p. 14 48. ref References references Category Sedimentology nl Neomorfose ... more details
Orphan date February 2009 Taxobox regnum Animalia phylum Mollusca ordo Serialia classis Polyplacophora subclassis Paleoloricata genus Heloplax genus authority Cherns 1998 type species Heloplax papilla Heloplax is a worm like mollusc . Its soft parts are preserved in three dimensions in the Silurian Herefordshire lagerstatte its disarticulated valves are known from other Silurian deposits. ref name Sutton2004 cite doi 10.1111 j.0031 0239.2004.00374.x ref It is very bizarre by modern standards it bears serially repeated units, and has spines. It probably falls somewhere between the aplacophorans and polyplacophora its valves were composed of aragonite ref name Sutton2004 References reflist Category Chitons Chiton stub ... more details
Image StenotremaFlorida1.jpg thumb right 200px The shell of Stenotrema florida , a land snail. The periostracum is an organic layer of protein which, in this species, is developed into minute hairs, giving the snail a velvety look and feel Conchiolin sometimes referred to as conchin and perlucin are complex protein s which are secreted by a mollusc s outer epithelium the mantle mollusc mantle . These proteins are part of a matrix of organic macromolecules, mainly proteins and polysaccharides, that assembled together form the microenvironment where crystals nucleate and grow. This organic matrix also holds and binds to the crystals of aragonite which give such shells their stiffness. The ion s necessary to form calcium carbonate are also secreted by the mantle, but it is the tailored environment created by the organic matrix which causes aragonite rather than calcite crystals to nucleate, in much the same way that collagen nucleates hydroxyapatite crystals. Conchiolin serves as a relatively flexible, crack deflecting extracellular matrix matrix for the mineral aggregate composite aggregate particles its strength and the strong bonding of perlucin can in some cases such as in the formation of nacre give the finished material an impressive level of toughness . As well as providing a matrix into which the hard calcium carbonate part of the shell is precipitated, many species of mollusks such as the land snail shown above also have an outer shell layer called the periostracum which is composed of the protein conchiolin. See also Mollusc shell Periostracum Corneous Chitin Tectin secretion Tectin Sporopollenin External links http www.jcb.org cgi content abstract 9 2 395 Structure of the conchiolin cases of the prisms in Mytilus edulis , Charles Gr goire, 1960 protein stub Category Proteins Category Molluscs de Conchiolin es Conquiolina fr Conchyoline it Conchiolina nl Conchioline pl Konchiolina pt Conchiolina ... more details
Merge to Live rock date February 2011 discuss Talk Live rock Merger proposal Base rock is a generic term for aragonite rocks which have no bacterial organisms or coralline algae coralline algae growing in or on the rock. ref http saltaquarium.about.com od liverockberlinsetups a aaliverockfaq.htm What is Live Rock in About.com ref Base rock is often used as filler rock in the marine aquarium as it is much cheaper to purchase than live rock . In time, base rock will become live, and will be colonized by coralline. Base rock can also be made from artificial rock called aragocrete which is a hand made concrete from combining crushed aragonite , sand , and Portland cement . Care must be taken when using these rocks as it starts off with a very high pH value that is detrimental to the reef aquarium inhabitants. After allowing the cement to dry, the pieces are sometimes acid washed and then allowed to soak in fresh water for one or more months. They generally tend to be heavier and less attractive when compared to natural base rock. Recently base rock that is mined from inland ancient reefs has become a popular way to sustainably keep the aquarium trade going. This rock is either maricultured and sold as live rock, or can be purchased and grown in the home aquarium. References references See also Live rock Reef aquarium Marine aquarium Aquarium DEFAULTSORT Base Rock Category Aquaria ... more details
Calcareous sinter is a freshwater calcium carbonate deposit, also known as calc sinter . Deposits are characterised by low porosity and well developed lamination. Calcareous sinter should not be confused with siliceous sinter , which the term sinter more frequently refers to. It has been suggested that the term sinter should be restricted to siliceous spring deposits and be dropped for calcareous deposits entirely. Features Calcareous sinter is characterised by laminations of prismatic crystals growing perpendicular to the substrate laminations are separated by thin layers of microcrystalline carbonate. ref Fl gel, E. 2004. Microfacies of Carbonate Rocks . Germany Spring Verlag. ISBN 3 540 22016 X ref Macrophyte s are absent, consequently porosity is very low. Exclusion of species is due either to high temperature travertine , high pH ion content tufa or absence of light speleothem s . Pedley 1990 ref Pedley, H.M. 1990. Classification and environmental models of cool freshwater tufas. Sedimentary Geology 68 , pp. 143 154. ref suggests the term be abandoned in favour of tufa for ambient temperature deposits and presumably travertine for geothermally heated deposits . This avoids any potential confusion with siliceous sinter and prevents deposits formed in different environmental conditions hot spring deposits, cold spring deposits and speleothems are all lumped together under the term sinter from being amalgamated into one group. Geochemistry Deposits are formed from either calcite or aragonite . Precipitation is brought about by degassing of CO sub 2 sub , which decreases the solubility of calcite aragonite. See tufa Geochemistry tufa geochemistry Notable Deposits gallery Image Kalksinter.JPG Pure calc sinter, typical for aqueduct s and all kinds of water facilities. Image Eifelwasserleitung05.jpg Roman aqueduct in Germania Inferior . Eifel Aqueduct , clogged by fine sinter. Image Travertine mound Bridgeport CA.jpg Deposits of several thousand years of calc sinter t ... more details
image Pb29 cut2.jpg frame Ceratoporella nicholsoni , cut specimen from Pedro Bank , Caribbean Sea , about 15 cm wide. Brown sponge tissue covers white massive aragonite skeleton . Sclerosponges are sea sponge sponge s with a soft body that covers a hard, often massive skeleton made of calcium carbonate , either aragonite or calcite . Because of their long life span 500 1,000 years it is thought that analysis of the aragonite skeleton s of these sponges could extend data regarding ocean temperature , salinity , and other variables farther into the past than has been previously possible. Their dense skeletons are deposited in an organized chronological manner, in concentric layers or bands. The layered skeletons look similar to reef coral s. Therefore sclerosponges are also called coralline sponges . Sclerosponges were first proposed as a class of sponges, Sclerospongiae , in 1970 by Hartman and Goreau. ref cite journal author W. D. Hartman and T. F. Goreau year 1970 title Jamaican coralline sponges Their morphology biology morphology , ecology and fossil relatives journal Symp. Zool. Soc. Lond. volume 25 pages 205 243 Cited by http mgg.rsmas.miami.edu groups sil work1.htm . ref However, it was later found by Vacelet that sclerosponges occur in different classes of sea sponge Porifera . ref cite journal author J. Vacelet year 1985 title Coralline sponges and the evolution of the Porifera journal System. Assoc. Spec. volume 28 pages 1 13 ref That means that sclerosponges are not a closely related Taxonomy taxonomic group of sponges. Like bat s and bird s that independently developed the ability to fly, different sponges developed the ability to build a calcareous skeleton independently and during different times in Geologic History of Earth Earth history . Fossil sclerosponges are already known from the Cambrian Period Cambrian period. ref cite journal author J. Reitner year 1992 title Coralline Spongien. Der Versuch einer phylogenetisch taxonomischen Analyse journal B ... more details
Context date October 2009 Paraphyletic group regnum Animalia included Halkierids Chancellorids The Coelosclerithophorans are a polyphyletic group of organisms bearing hollow sclerites made of aragonite . Their skeletons may be homologous to those of the molluscs, ref name Bengtson1992 Cite journal author Bengtson, S. year 1992 title The cap shaped Cambrian fossil Maikhanella and the relationship between coeloscleritophorans and molluscs journal Lethaia volume 25 issue 4 pages 401 420 doi 10.1111 j.1502 3931.1992.tb01644.x url http www.blackwell synergy.com doi abs 10.1111 j.1502 3931.1992.tb01644.x postscript None ref and Halkieria looks very much like a polyplacophoran . The shells of this group and the molluscs appear to have originated in the same fashion. ref name Bengtson1992 However, there are several reasons to doubt this relationship, ref name Yochelson1993 cite doi 10.1111 j.1502 3931.1993.tb01509.x ref many of which may not pass muster. ref name Bengtson1993 cite doi 10.1111 j.1502 3931.1993.tb01510.x ref There are two groups within the coeloscleritophorans the Sachitid s, to which Halkieria and Wiwaxia belong, and the Chancellorids . The Ediacaran fossil Ausia fenestrata Ausia has been touted as an ancestral intermediate between both of these groups. ref walcott2009 Dzik ref These are common constituents of Lower Cambrian small shelly fossil assemblages. References reflist Category Cambrian animals paleo stub ... more details
Image California Murphys Mercer cave1.jpg thumb 100px Image California Murphys Mercer cave2.jpg thumb 100px Mercer Caverns are located outside of Murphys, California Murphys in Calaveras County California . They are named after the gold prospector Walter J. Mercer who discovered the cave s around 1885 and filed a claim. They were later renamed as caverns . The caverns have a large number of speleothem s, stalactite s, and stalagmite s. Under the limestone calcite are a range of aragonite minerals that are pure CaCO3 . ref cite web url http www.showcaves.com english usa showcaves Mercer.html title Mercer Caverns publisher accessdate 2007 03 28 ref See also Stalagmite Stalactite Notes references External links http www.mercercaverns.com Mercer Caverns official site http www.viamagazine.com top stories articles caves98.asp Exploring the Caves of Calaveras coord missing Calaveras County, California Category Landforms of Calaveras County, California Category Limestone caves Category Show caves in the United States Category Geology stubs Category Caves of California Category Visitor attractions in Calaveras County, California US geology stub ... more details
automatic taxobox fossil range geo range Pennsylvanian ref ref name cite jstor 1300377 cite jstor 1300377. ref authority Johnson, 1956 subdivision bold species list A. delicatium Johnson, 1956 A. MISSOURIENSUM Johnson, 1956 type confusing date December 2010 Archaeolithophyllum is a genus of conceptacle bearing red alga that falls in the coralline stem group that somewhat resembles Lithophyllum ref name cite jstor 1300377 ref Cite doi 10.3732 ajb.91.2.214 ref it s the only Palaeozoic coralline to bear clear conceptacles, ref name Cozar2006 cite doi 10.1016 j.geobios.2005.09.002 ref although the earlier Graticula does bear reproductive structures. ref name Brooke2007 cite doi 10.1111 j.1502 3931.1998.tb00506.x ref It mineralized using aragonite. ref name Cozar2006 Its conceptacles are cone shaped protrusions that extend outwards from the thallus surface. ref name Wray1964 It probably encrusted muddy or sandy surfaces. ref name Wray1964 cite journal journal Kansas Geological Survey, Bulletin volume 170 issue 1 year 1964 title Archaeolithophyllum , an Abundant Calcareous Alga in Limestones of the Lansing Group Pennsylvanian , Southeastern Kansas author John L. Wray url http www.kgs.ku.edu Publications Bulletins 170 1 ref See also Stem coralline see also References Reflist Category Red algae Rhodophyta stub ... more details
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