Corrections and further discussion of the primary magmas of mid- ocean ridge basalts, 1 and 2

Abstract

An error has been detected in the methodology for estimating batch melt compositions from plagioclase and spinel lherzolites at mantle conditions presented by Kinzler and Grove (1992a,b). In a mass balance calculation employed by K&G the melt fraction was not properly transformed from weight units to molar units, resulting in an overestimate of the effective melt fraction employed in the calculation of the Mg of the melt, at melt fractions greater than 0.01. Using the corrected methodology the abundance of FeO in melts produced via batch melting increases as melt fraction increases from 0.01 to 0.20. The methodology of K&G is used to estimate the mantle temperature, average pressure of melting and average extent of melting beneath a mid-ocean ridge segment from the FeO and Na2O content of a mid-ocean ridge basalt from that segment. -from Authors