Halite-sylvite thermoelasticity

  1. Get@NRC: Halite-sylvite thermoelasticity (Opens in a new window)
AuthorSearch for: ; Search for: ; Search for: ; Search for: ; Search for: ; Search for:
Journal titleAmerican Mineralogist
Pages204210; # of pages: 7
AbstractUnit-cell volumes of four single-phase intermediate halite-sylvite solid solutions have been measured to pressures and temperatures of ?28 kbar and ?700 °C. Equation-of-state fitting of the data yields thermal expansion and compressibility as a function of composition across the chloride series. The variation of the product ?0.K0 is linear (ideal) in composition between the accepted values for halite and sylvite. Taken separately, the individual values of ?0 and K0 are not linear in composition. ?0 shows a maximum near the consolute composition (XNaCl = 0.64) that exceeds the value for either end-member. There is a corresponding minimum in K0. The fact that the ?0.K0 product is variable (and incidentally so well behaved as to be linear across the composition series) reinforces the significance of the complementary maxima and minima in ?0and K0 (significantly, near the consolute composition). These extrema in ?0and K0 provide an example of intermediate properties that do not follow simply from values for the end-members. Cell volumes across this series show small, well-behaved positive excesses, consistent with K-Na substitution causing defects through lattice mismatches. Barrett and Wallace (1954) showed maximum defect concentrations in the consolute region. Defect-riddled, weakened structures in the consolute region are more easily compressed or more easily thermally expanded, providing an explanation for our observed ?0 and K0 variations. These compliant, loosened lattices should resist diffusive transfer less than non-defective crystals and, hence, might be expected to show higher diffusivities. Tracer diffusion rates are predicted to peak across the consolute region as exchange diffusion rates drop to zero.
Publication date
Peer reviewedNo
NRC publication
This is a non-NRC publication

"Non-NRC publications" are publications authored by NRC employees prior to their employment by NRC.

NPARC number12329028
Export citationExport as RIS
Report a correctionReport a correction
Record identifier990580b3-e465-45f2-b069-360b11ce8cec
Record created2009-09-10
Record modified2016-05-09
Bookmark and share
  • Share this page with Facebook (Opens in a new window)
  • Share this page with Twitter (Opens in a new window)
  • Share this page with Google+ (Opens in a new window)
  • Share this page with Delicious (Opens in a new window)