资源描述：
《Closure in crystal size distributions (CSD)， verification of CSD calculations，.pdf》由会员上传分享，免费在线阅读，更多相关内容在学术论文-天天文库。
1、AmericanMineralogist,Volume87,pages171–175,2002LETTERSClosureincrystalsizedistributions(CSD),verificationofCSDcalculations,andthesignificanceofCSDfansMICHAELD.HIGGINS1,*1SciencesdelaTerre,UniversitéduQuébecàChicoutimi,Chicoutimi,G7H2B1,CanadaABSTRACTCrystalsizedistribut
2、ion(CSD)measurementsaresusceptibletotheclosureproblem,justlikechemicalcompositions.Initssimplestformthismeansthatthetotalcrystalcontentofarockcannotexceed100%.Wherechemicalorthermaleffectslimitthetotalquantityofasinglephase,closurecanoccuratlowervolumetricphaseproportio
3、ns.ThismeansthatpartsoftheCSDdiagram[ln(populationdensity)vs.size]arenotaccessible.Ifthevolumetricphaseproportionisconstant,thenstraightCSDswillappeartorotatearoundapointatsmallsizesgivingafanofCSDs.Thesefansaresignificantanddoshowchangesincrystalsizesthatcanbeinterpret
4、edintermsofmagmaticpro-cesses.However,thecorrelationbetweentheslopes(orcharacteristiclengths)andinterceptsofindividualCSDsinafamilyisnotsignificant,butjustaconsequenceoftheconstantphasepropor-tioneffect.Manyothergraphs,suchascharacteristiclengthvs.volumetricphaseproport
5、ion,cangivemoreinformationonmagmaticprocesses.INTRODUCTIONCLOSUREANDCONSTANTPHASEPROPORTIONINCrystalsizedistribution(CSD)studiesofigneousandmeta-CSDMEASUREMENTSmorphicrockshavebecomemorepopularrecentlypartlybe-Weareconcernedherewiththeeffectsofconstantphasecauseithasbee
6、nrealizedthattheyareaquantitativemethodproportiononCSDs,however,Iwillshowlaterthatevenquiteoflookingatigneousprocessesthatiscomplementarytolargevariationsinvolumetricphaseproportionscanshowthegeochemicalstudies(e.g.,Cashman1990;Higgins1999;Marshsameeffects.Clearly,closu
7、reisjustaspecialcaseofthismore1998).Anotherreasonmaybetherecentavailabilityofsimplegeneralproblem,wherethevolumetricphaseproportionisequalmethodsofcalculatingCSDsfrommeasurementsintwodi-toone.mensions,suchasthinsections(e.g.,Higgins2000;PetersonThevolumetricproportionof
8、phasei,Vi,iscalculatedby1996).integrationofthevolumeofallthecrystals:Thecrystalcontentofarockcannotexceed100%,
