Home

About

Advanced Search

Browse by Discipline

Scientific Societies

E-print Alerts

Add E-prints

E-print Network
FAQHELPSITE MAPCONTACT US


  Advanced Search  

 
Determination of melt influence on divalent element partitioning between anorthite and CMAS melts
 

Summary: Determination of melt influence on divalent element
partitioning between anorthite and CMAS melts
Sarah A. Miller *, P.D. Asimow, D.S. Burnett
Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena CA 91125, USA
Received 12 January 2006; accepted in revised form 16 June 2006
Abstract
We propose a theory for crystal-melt trace element partitioning that considers the energetic consequences of crystal-lattice strain, of
multi-component major-element silicate liquid mixing, and of trace-element activity coefficients in melts. We demonstrate application of
the theory using newly determined partition coefficients for Ca, Mg, Sr, and Ba between pure anorthite and seven CMAS liquid com-
positions at 1330 °C and 1 atm. By selecting a range of melt compositions in equilibrium with a common crystal composition at equal
liquidus temperature and pressure, we have isolated the contribution of melt composition to divalent trace element partitioning in this
simple system. The partitioning data are fit to Onuma curves with parameterizations that can be thermodynamically rationalized in terms
of the melt major element activity product đaAl2O3
̃đaSiO2
̃2
and lattice strain theory modeling. Residuals between observed partition coef-
ficients and the lattice strain plus major oxide melt activity model are then attributed to non-ideality of trace constituents in the liquids.
The activity coefficients of the trace species in the melt are found to vary systematically with composition. Accounting for the major and
trace element thermodynamics in the melt allows a good fit in which the parameters of the crystal-lattice strain model are independent of
melt composition.

  

Source: Asimow, Paul D. - Division of Geological and Planetary Sciences, California Institute of Technology,

 

Collections: Geosciences