Studies in the System CaCO3-MgCO3-FeCO3: 1. Phase Relations; 2. A Method for Major-Element Spectrochemical Analysis; 3. Compositions of Some Ferroan Dolomites

Goldsmith, Julian R.; Graf, Donald L.; Witters, Juanita; Northrop, D.A.

doi:10.1086/626865

Cited by 102 publications

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“…1a) and confirmed the presence of a three phase field as observed by Goldsmith et al (1962). Increasing the temperature from 400 to 500°C, the three phase field moves toward the join CaCO 3 -FeCO 3 (Fig.…”

Section: Introductionsupporting

confidence: 81%

“…1b, c). At temperatures above 650°C, Goldsmith et al (1962) demonstrate the presence of two 2-phase fields (black dots in Fig. 1), where dolomite coexists with calcite or magnesite, resembling the phase relations of the system CaCO 3 -MgCO 3 (Goldsmith and Heard 1961).…”

Section: Introductionmentioning

confidence: 85%

“…The second 2-phase field is a broad dolomite-magnesite miscibility gap that extends from the Mg to the Fe side, where siderite coexists with Ca 0.7 Fe 0.3 CO 3 at 700°C and with Ca 0.6 Fe 0.4 CO 3 at 800°C. Furthermore, at temperature below 700°C, Goldsmith et al (1962) obtained coexistence of Fe dolomite, Fe calcite and Mg siderite defining a threephase field (Fig. 1b), which broadens with decreasing temperature.…”

Section: Introductionmentioning

confidence: 93%

“…The first experimental study describing phase relations in the system CaCO 3 -MgCO 3 -FeCO 3 was conducted by Goldsmith et al (1962), who determined isothermal sections at temperatures between 600 and 800°C at 1.5 GPa (Fig. 1b, c).…”

Section: Introductionmentioning

confidence: 99%

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Ternary Ca–Fe–Mg carbonates: subsolidus phase relations at 3.5 GPa and a thermodynamic solid solution model including order/disorder

Franzolin

Schmidt

Poli

2010

Contrib Mineral Petrol

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Subduction carries atmospheric and crustal carbon hosted in the altered oceanic crystalline basement and in pelagic sediments back into the mantle. Reactions involving complex carbonate solid solutions(s) lead to the transfer of carbon into the mantle, where it may be stored as graphite/diamond, in fluids or melts, or in carbonates. To constrain the thermodynamics and thus reactions of the ternary Ca-Mg-Fe carbonate solid solution, piston cylinder experiments have been performed in the system CaCO 3 -MgCO 3 -FeCO 3 at a pressure of 3.5 GPa and temperatures of 900-1,100°C. At 900°C, the system has two miscibility gaps: the solvus dolomite-calcite, which closes at X MgCO3 *0.7, and the solvus dolomite-magnesite, which ranges from the Mg to the Fe side of the ternary. With increasing temperature, the two miscibility gaps become narrower until complete solid solutions between CaCO 3 -Ca 0.5 Mg 0.5 CO 3 is reached at 1,100°C and between CaCO 3 -FeCO 3 at 1,000°C. The solvi are characterized by strong compositional asymmetry and by an order-disorder mechanism. To deal with these features, a solid solution model based on the van Laar macroscopic formalism has been calculated for ternary carbonates. This thermodynamic solid solution model is able to reproduce the experimentally constrained phase relations in the system CaCO 3 -MgCO 3 -FeCO 3 in a broad P-T range. To test our model, calculated phase equilibria were compared with experiments performed in carbonated mafic protolithes, demonstrating the reliability of our solid solution model at pressures up to 6 GPa in complex systems.

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Section: Introductionsupporting

confidence: 81%

Section: Introductionmentioning

confidence: 85%

Section: Introductionmentioning

confidence: 93%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Ternary Ca–Fe–Mg carbonates: subsolidus phase relations at 3.5 GPa and a thermodynamic solid solution model including order/disorder

Franzolin

Schmidt

Poli

2010

Contrib Mineral Petrol

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“…The α o dimension for pure calcite is 4.9900 Å (Graf, 1961(Graf, , p. 1285, whereas α o for 17841(CC) = 4.940 Å; 42(CC) = 4.917 Å; and 48(CC) = 4.924 Å. Assuming Fe+2 is the only proxy ing cation, this means from 4 to 6 mole per cent FeC03 is in calcite, according to formulae in Goldsmith et al (1962). A recent paper by lindholm and Finkelman (1972) related color of stain to iron content in calcite; by their criteria the Site 178 calcite cements should have about 4 to 6 mole percent FeCθ3 > which correlates well with the cell-demension values.…”

Section: Cementsmentioning

confidence: 99%

Petrology of Indurated Sandstones, Leg 18, Deep Sea Drilling Project

Hayes¹

1973

Initial Reports of the Deep Sea Drilling Project

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Sandstones from Hole 177A (offshore north end of Vancouver Island) and Sites 178 and 181 (Gulf of Alaska) are compositionally immature feldspathic arenites containing abundant Plagioclase. Their compositions lie at the feldspar-rich end of the compositional spectrum for circum-Pacific sandstones. They probably were derived from andesitic-granodioritic-metamorphic arcs of typical arc-trench systems at times when plutons were greatly unroofed and volcanic activity was temporarily diminished.Sandstones from the Alaskan sites were cemented by calcite very early in diagenesis, which prevented further diagenetic alteration. They have very little silt and clay matrix, and the clays they do have are similar to those in associated shales. The calcite cement prevented grain compaction, so that the sand grains are openly packed in the cement.In contrast, sandstones from Hole 177A had a very complex diagenetic history. A possible 56-meter-thick sand body of probably Early Pliocene age may rest on acoustic basement about 520 meters below the sea floor in 2000 meters of water. The sand body is overlain by submarine-fan turbidites and hemipalagic muds, and may well be filling a submarine channel. Compaction of sand grains during basin subsidence and burial diagenesis reduced original porosity somewhat, but authigenic chlorite filling pores and replacing grains destroyed most of the porosity. After chlorite formation, calcite filled in the little remaining pore space and replaced some sand grains. Then the sediments at Hole 177A were uplifted, possibly because of the movements at the triple junction of the American, Pacific, and Juan de Fuca lithospheric plates where the site is located. The sand body and associated rocks were fractured in the process. Acid solutions of unknown origin permeated along hairline fractures and dissolved the chlorite and calcite cements, creating channels of intergranular porosity locally of 30 or 40 percent. Some of this solution porosity was filled later by precipitation of sparry anhydrite.

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Phase Diagrams of Carbonate Materials at High Pressures, with Implications for Melting and Carbon Cycling in the Deep Earth

Litasov

Shatskiy

Podborodnikov

et al. 2020

Geophysical Monograph Series

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In this chapter, we review phase diagrams of alkali and alkaline earth carbonates at high pressures, particularly simple, binary, and ternary systems, which were recently constrained at pressures of 3 and 6 GPa. These studies revealed a number of new alkali-alkaline earth double carbonates. Major transformations of high-pressure carbonates, including changes in carbon coordination, spin transition, and valence state in Fe-bearing carbonates up to the lower mantle levels, were also discussed. We emphasize the importance of carbonate systems for understanding the low-degree partial melting of carbonated mantle rocks and explaining carbonate inclusions in diamond and other deep-seated minerals. The question of carbonate stability versus the presumably reduced nature of the deep Earth's mantle provides significant impact on the further study of material transport and deep volatile cycle through the history of our planet.

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Studies in the System CaCO₃-MgCO₃-FeCO₃: 1. Phase Relations; 2. A Method for Major-Element Spectrochemical Analysis; 3. Compositions of Some Ferroan Dolomites

Cited by 102 publications

References 0 publications

Ternary Ca–Fe–Mg carbonates: subsolidus phase relations at 3.5 GPa and a thermodynamic solid solution model including order/disorder

Ternary Ca–Fe–Mg carbonates: subsolidus phase relations at 3.5 GPa and a thermodynamic solid solution model including order/disorder

Petrology of Indurated Sandstones, Leg 18, Deep Sea Drilling Project

Phase Diagrams of Carbonate Materials at High Pressures, with Implications for Melting and Carbon Cycling in the Deep Earth

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