| Registro completo |
| Provedor de dados: |
OceanDocs
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| País: |
Belgium
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| Título: |
Thermochemistry of strontium incorporation in aragonite from atomistic simulations
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| Autores: |
Grau-Crespo, R.
Ruiz-Hernández, S. E.
Ruiz-Salvador, A. R.
De Leeuw, N. H.
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| Data: |
2011-08-12
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| Ano: |
2010
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| Palavras-chave: |
1246
Aragonite
Coral reefs
Thermodynamic activity
Strontium
Strontium
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| Resumo: |
We have investigated the thermodynamics of mixing between aragonite (orthorhombic CaCO3) and strontianite (SrCO3). In agreement with experiment, our simulations predict that there is a miscibility gap between the two solids at ambient conditions. All SrxCa1 xCO3 solids with compositions 0.12 < x < 0.87 are metastable with respect to separation into a Ca-rich and a Sr-rich phase. The concentration of Sr in coral aragonites (x 0.01) lies in the miscibility region of the phase diagram, and therefore formation of separated Sr-rich phases in coral aragonites is not thermodynamically favorable. The miscibility gap disappears at around 380 K. The enthalpy of mixing, which is positive and nearly symmetric with respect to x = 0.5, is the dominant contribution to the excess free energy, while the vibrational and configurational entropic contributions are small and of opposite sign. We provide a detailed comparison of our simulation results with available experimental data. Se investigó la actividad termodinámica existente entre la mezcla de la aragonita y el estroncio. Se ofrecen todos los datos experimentales y los resultados de la simulación efectuada predicen que hay un vacío en condiciones de ambiente.
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| Tipo: |
Journal Contribution
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| Idioma: |
Inglês
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| Identificador: |
Geochimica et Cosmochimica Acta, 74(2010). p. 1320-1328
0016-7037
http://hdl.handle.net/1834/4103
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| Editor: |
Elsevier
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| Relação: |
doi:10.1016/j.gca.2009.10.049
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