Compositional and pressure effects on the solubility of H2O and CO2 in mafic melts
Compositional and pressure effects on the solubility of H2O and CO2 in mafic melts
复制标题
成分和压力对镁铁质熔体中 H2O 和 CO2 溶解度的影响
DOI:
10.1016/j.chemgeo.2014.09.001
复制
发表时间:
2014
期刊:
影响因子:
3.9
通讯作者:
Jakubiak A.
中科院分区:
文献类型:
--
作者:
Shishkina T.A;Botcharnikov R.E;Holtz F;Almeev R;Jazwa A;Jakubiak A.
The effect of the anhydrous composition on the solubilities of H2O and CO2in mafic melts varying from MORB to nephelinite was investigated experimentally between 50 and 500 MPa at 1200 to 1250 °C. In all compositions, CO2is only present as carbonate species in the quenched glasses. The concentrations of dissolved H2O and CO2have been analyzed by KFT (Karl–Fischer titration) and FTIR (Fourier-transform infrared spectroscopy). The Mid-Infrared (MIR) absorption coefficients for the H2O band at 3500 cm− 1are identical within error for all investigated melt compositions and equal to 59.2 ± 4 L/(mol∗ cm). The absorption coefficients for the carbonate bands vary in the range 306 ± 32 to 360 ± 24 L/(mol ∗ cm) for the 1430 cm− 1band and in the range 349 ± 25 to 394 ± 27 L/(mol ∗ cm) for the 1520 cm− 1band. However, a simple correlation with the melt composition could not be determined.Water solubility in mafic to intermediate melts increases slightly with the total alkali content and the effect of composition is more pronounced at higher pressures. At 500 MPa, the solubility of H2O in melts coexisting with nearly pure H2O fluids varies from 8.8 to 9.5 wt.% H2O. A strong effect of melt composition on the solubility of CO2is observed at all investigated pressures. For instance, at 500 MPa, mafic melts coexisting with nearly pure CO2fluids can dissolve from around 0.32 to more than 1.30 wt.% CO2as melt composition changes from tholeiite to nephelinite. The compositional effect on the solubility of CO2in melts coexisting with pure CO2fluid is best described by non-linear (exponential) correlations with compositional parameters such as the parameterΠproposed by Dixon (1997; American Mineralogist, 82: 368–378) or structural parameters (e.g., nonbridging oxygen per tetrahedrally coordinated cation). The obtained relationships are used to propose empirically derived equations of the form ln(CO2) = 1.150 · lnP+ 6.71 ·Π* − 1.345, where CO2is the solubility of CO2in silicate melts in wt.% (at 1200 to 1250 °C),Pis pressure in MPa andΠ* is a compositional parameter (Π* = Ca2 ++ 0.8K++ 0.7Na++ 0.4Mg2 ++ 0.4Fe2 +) / (Si4 ++ Al3 +) with cations expressed as cation fractions in melt.
登录
查看更多内容
影响因子:
5
作者:
Iacono-Marziano, Giada;Morizet, Yann;Gaillard, Fabrice
通讯作者:
Gaillard, Fabrice
DOI:
--
发表时间:
1975
期刊:
影响因子:
--
作者:
B. Mysen;R. Arculus;D. Eggler
通讯作者:
D. Eggler
DOI:
--
发表时间:
1992
期刊:
影响因子:
--
作者:
Naresh Pandya;D. W. Muenow;Shiv k. Sharma
通讯作者:
Shiv k. Sharma
DOI:
--
发表时间:
1975
期刊:
影响因子:
--
作者:
C. Wayne Burnham
通讯作者:
C. Wayne Burnham
影响因子:
3.5
作者:
P. Richet;A. Whittington;F. Holtz;H. Behrens;S. Ohlhorst;M. Wilke
通讯作者:
M. Wilke