RamanpeaksofvarioushydratesintheH2O-NaCl-CaCl2systemhavebeenpreviouslyidentified,butaquantitativerelationshipbetweentheRamanpeaksandXNaCl(i.e.,NaCl/(NaCl+CaCl2))hasnotbeenestablished,mainlyduetothedifficultytofreezethesolutions.Thisproblemwassolvedbyaddingaluminapowdertothesolutionstofacilitatenucleationofcrystals.Cryogenic(-185oC)Ramanspectroscopicstudiesofalumina-spicedsolutionsindicatethatXNaClislinearlycorrelatedwiththetotalpeakareafractionofhydrohalite.Capsulesofsolutionsmadefromsilicacapillarywerepreparedtosimulatefluidinclusions.Mostoftheseartificialfluidinclusionscouldnotbetotallyfrozenevenattemperaturesaslowas-185oC,andthetotalpeakareafractionofhydrohaliteisnotcorrelatedlinearlywithXNaCl.However,thedegreeofdeviation(?XNaCl)fromthelinearcorrelationestablishedearlierisrelatedtotheamountofresidualsolution,whichisreflectedbytheratio(r)ofthebaseline"bump"area,resultingfromtheinterstitialunfrozenbrinenear3435cm-1,andthetotalhydratepeakareabetween3350and3600cm-1.Alinearcorrelationbetween?XNaClandrisestablishedtoestimateXNaClfromcryogenicRamanspectroscopicanalysisforfluidinclusions.
