Abstract
The isotopic ratios of magnesium in rocks coming from the upper mantle and Bruderheim chondrite were measured by a solid-source mass spectrometer. There is no significant difference in 25Mg/24Mg and 26Mg/24Mg between materials constituting the mantle and Bruderheim chondrite within the limits of 95% confidence. The standard errors of both 25Mg/24Mg and 26Mg/24Mg measurements of a sample were about 0.5%.
