title: Estimating proportions in petrographic mixing equations by least-squares approximation.
abstract: Petrogenetic hypotheses involving fractional crystallization, assimilation, or mixing of magmas may be expressed and tested as problems in leastsquares approximation. The calculation uses all of the data and yields a unique solution for each model, thus avoiding the ambiguity inherent in graphical or trial-and-error procedures. The compositional change in the 1960 lavas of Kilauea Volcano, Hawaii, is used to illustrate the method of calculation.
authors.forename: W B
authors.initials: WB
authors.lastname: Bryan
authors.forename: L W
authors.initials: LW
authors.lastname: Finger
authors.forename: F
authors.initials: F
authors.lastname: Chayes