high pressure calcite

DEFORMATION OF SINGLE CALCITE CRYSTALS UNDER HIGH

calcite at high pressure was so much lower than that of the aggregat Marble has been deformed 24/6 without rupture at 10 000 atmospheres and Solenhofen limestone has been deformed more than 30/p at the same pressure without rupture but as shown the single crystals of cal-cite ruptured after only 7/e deformation at 10 060 atmospher...

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Decomposition and Transformation of Calcite

Calcite-I sheared at high pressure not only transformed to its polymorphism but also decomposed to compounds and simple substanc Most of them are high-pressure substances and they remain at atmospheric pressure References Akahama Y Kawamura H Häusemann D Hanfland M Shimomura O 1995 New high-pressure...

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The ionic conductivity in high

Ionic conductivity of polycrystalline calcite containing varying amounts of PO 4 / 3- ions was measured in the pressure range of 1 6 GPa and at room temperature Electrical conductivity increased with pressure corresponding to the phase transition of calcite I to calcite II The conductivity in calcite III decreased exponentially with pressure...

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Phase transitions and Raman spectra of calcite at high

directly to calcite-I with decreasing pressure without the appearance of calcite-Il in either case Thus it appears that the existence ofcalcite-Il in a high-pressure experi-ment is sensitive to the shear stress in the pressure vessel On the other hand we sometimes also observed calcite-II in the pressure range 10-18 kbar in our hydrostatic...

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Compositional zoning of calcite in a high

Calcite in former aragonite-dolomite-bearing calc-schists from the ultrahigh-pressure metamorphic UHPM oceanic complex at Lago di Cignana Valtournanche Italy preserved different kinds of zoning patterns at calcite grain and phase boundari These patterns are interpreted in terms of lattice diffusion and interfacial mass transport linked with a heterogeneous distribution of fluid and its...

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The crystal structure of calcite III

study of calcite at high pressure using diffraction of synchrotron X-rays Fiquet et al 1994 report an extrapolated zero pressure density of 314 Mg/m 3 for calcite HI The crystal structure of aragonite is well known and its equation of state parameters have recently been refined at pressures to 7GPa...

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The calcite

the exact correspondence of the present high-pressure results to previous X-ray determina-tions of one-atmosphere phase relations one of these two polymorphs is identified as a calcite CO structure having ordered CO3 groups and the other as a calcite-like structure in which the groups display rotational disordering about their triad ax...

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Phase transitions and Raman spectra of calcite at high

High-pressure phase transformations and Raman spectra of calcite at room temperature were studied using single crystals in a diamond-anvil cell under hydrostatic presswe Calcite displays two reversible phase transformations at high pressures and room temperature We found however that transformation to calcite-Il is more likely to occur under nonhydrostatic conditions...

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Calcite Mineral information data and localiti

Calcite Group Calcite-Rhodochrosite Seri A very common and widespread mineral with highly variable forms and colours Calcite is best recognized by its relatively low Mohs hardness 3 and its high reactivity with even weak acids such as vinegar plus its prominent rhombohedral cleavage in...

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CARBONATE EQUILIBRIA

Calcium carbonate in water with a fixed partial pressure of carbon dioxide For the case of a fixed partial pressure of carbon dioxide and calcium carbonate dissolved in the aqueous phase one more equation is need to describe the system This is the solubility product of calcium carbonate = K CaCO Ca CO o CaCO 3 2 - 3 2 3 19...

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Recrystallization textures of high

The conditions and mechanisms of deformation and metamorphism of subducted sedimentary rocks influence the physical and chemical evolution of convergent plate margins However the high-pressure HP grain-scale deformation mechanisms of major crustal minerals eg quartz calcite are not as well known as those of minerals in HP meta-mafic and ultramafic rocks in part because of the lack of...

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LETTER A high

A high-pressure phase transition of calcite-III KRYSTLE CATALLI AND QUENTIN WILLIAMS Department of Earth Sciences University of California Santa Cruz 1156 High Street Santa Cruz California 95064 USA ABSTRACT We document the presence of a high pressure phase transition in metastable calcite-III using infrared...

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Aragonite pseudomorphs in high

Aragonite a high-pressure polymorph of calcite is the stable calcium carbonate mineral during metamorphism at blueschist to eclogite facies conditions Carlson 1983 Nevertheless aragonite is rare in high-pressure marbles because it transforms to calcite during exhumation unless the temperature is unusually low Carlson and Rosenfeld 1981...

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PDF The crystal structure of calcite III

The crystal structure of calcite III has been deduced from existing high pressure powder X-ray diffraction patterns based on the assumption that it is a displacive modification of the calcite I...

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Properties of molten CaCO3 at high pressure Geochemical

Apr 30 2018 0183 32 Redfern SAT Angel RJ 1999 High-pressure behaviour and equation of state of calcite CaCO 3 Contributions to Mineralogy and Petrology 134 102-106 Compared to silicate melts Fig 2 molten CaCO 3 is less compressible than basalt Sakamaki et al 2006...

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