A local area of the Kap Edvard Holm Upper Layered Series gabbro has been converted into a quartz albite-epidote ilmenite rock by leaching of iron and with a net mass loss. Among the textural changes is the dissolution of the magnetite matrix of magnetite-ilmenite lamellar intergrowths. This is an extreme example of a series of low-temperature changes occurring throughout the intrusion due to the reaction of the gabbro with a volatile-rich phase which separated during the magmatic stage and remained trapped within the walls of the intrusion. The Fe-rich fluid formed by this autometa-somatic process is similar to those responsible for the genesis of Cornwall-type magnetite deposits. The probable temperature range for the process is 400–550°C.