A Solid Solution between Calcite and Dolomite

Chave, Keith E.

doi:10.1086/625949

Cited by 159 publications

(69 citation statements)

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“…All data of the present study fall into a compositional interval between 10 and 17 mol% Mg. A linear relationship between d 104 value and Mg concentration of skeletal magnesian calcites was first reported by Chave (1952) over the range 2−16 mol% Mg. Considering compositions between 0 and 20 mol% Mg of biogenic and inorganic magnesian calcites, Mackenzie et al (1983) concluded the d 104 trend is equivalent to a straight line from calcite to disordered dolomite or magnesite.…”

Section: X-ray Diffraction Analysismentioning

confidence: 79%

Skeletal mineralogy of geniculate corallines: providing context for climate change and ocean acidification research

Williamson¹,

Najorka²,

Perkins³

et al. 2014

Mar. Ecol. Prog. Ser.

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Marine species depositing high-magnesium (Mg) calcite (> 8% MgCO 3 ) are projected to be among the first to show response to the impacts of climate change, i.e. increased sea surface temperature (SST) and ocean acidification (OA), given the increasing solubility of calcite in seawater with increasing Mg content. Temperature is a major driver of Mg incorporation into the skeletons of calcifying macroalgae, and thus climate change may induce deposition of more ), than other temperate calcifying macroalgae studied to date. Over the period 1850−2010, no change in the magnitude of Mg incorporation by C. officinalis was detected in herbarium samples. However, the strong relationship between SST and Mg content indicates that projected increases in SST by 2100, which are far greater than temperature increases that occurred between 1850−2010, could have substantial impact on geniculate coralline algae skeletal mineralogy, and must be considered synergistically with the effects of OA.

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Section: X-ray Diffraction Analysismentioning

confidence: 79%

Skeletal mineralogy of geniculate corallines: providing context for climate change and ocean acidification research

Williamson¹,

Najorka²,

Perkins³

et al. 2014

Mar. Ecol. Prog. Ser.

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show abstract

“…Samples were dispersed in KBr pellets. For calcium and magnesium content measurements, samples were dissolved in 1 N HNO $ , and were then analysed with a Perkin-Elmer 5100 GFAAS atomic absorption spectrometer, assuming that calcium and magnesium are the only two major cations existing in the minerals (Chave 1952 ;Raup 1966). …”

Section: Methodsmentioning

confidence: 99%

Design strategies of sea urchin teeth: structure, composition and micromechanical relations to function

Wang

Addadi

Weiner

1997

Phil. Trans. R. Soc. Lond. B

170

177

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SUMMARYThe teeth of sea urchins comprise a variety of different structural entities, all of which are composed of magnesium-bearing calcite together with a small amount of organic material. The teeth are worn down continuously, but in such a way that they remain sharp and functional. Here we describe aspects of the structural, compositional and micromechanical properties of the teeth of Paracentrotus li idus using scanning electron microscopy, infrared spectrometry, atomic absorption, X-ray diffraction and microindentation. The S-shaped single crystalline calcitic fibres are one of the main structural elements of the tooth. They extend from the stone part to the keel. The diameter of the fibres increases gradually from less than 1 µm at the stone tip to about 20 µm at the keel end, while their MgCO $ contents decrease from about 13 mol % to about 4.5 mol %. Each fibre is coated by a thin organic sheath and surrounded by polycrystalline calcitic discs containing as much as 35 mol % MgCO $ . This structure constitutes a unique kind of gradient fibre-reinforced ceramic matrix composite, whose microhardness and toughness decrease gradually from the stone part to the keel. Primary plates are also important structural elements of the tooth. Each primary plate has a very unusual sandwich-like structure with a calcitic envelope surrounding a thin apparently amorphous CaCO $ layer. This central layer, together with the primary plate\disc interface, improves the toughness of this zone by stopping and blunting cracks. The selfsharpening function of the teeth is believed to result from the combination of the geometrical shape of the main structural elements and their spatial arrangement, the interfacial strength between structural elements, and the hardness gradient extending from the working stone part to the surrounding zones. The sea urchin tooth structure possesses an array of interesting functional design features, some of which may possibly be applicable to materials science.

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“…The skeletal parts of calcareous marine organisms are composed of the minerals, calcite, aragonite and magnesian calcite (CHAVE, 1952(CHAVE, , 1954LOWENSTAM, 1954;KITANO and KANAMORI, 1966;KITANO et al, 1969). The study on the distribution of trace metals for these minerals is important for the understanding of the geo chemical behaviors of trace metals on the earth's surface.…”

Section: Introductionmentioning

confidence: 99%

Magnesian calcite synthesis from calcium bicarbonate solution containing magnesium and barium ions.

1979

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A Solid Solution between Calcite and Dolomite

Cited by 159 publications

References 0 publications

Skeletal mineralogy of geniculate corallines: providing context for climate change and ocean acidification research

Skeletal mineralogy of geniculate corallines: providing context for climate change and ocean acidification research

Design strategies of sea urchin teeth: structure, composition and micromechanical relations to function

Magnesian calcite synthesis from calcium bicarbonate solution containing magnesium and barium ions.

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