The Grasberg Igneous Complex (GIC) is host to one of the largest copper and gold porphyry-type ore deposits in the world. Previous fluid inclusion studies of Grasberg have reported homogenisation temperatures up to 700 ⁰C (the limit of the heating stage). However, in this study, quartz-hosted fluid inclusions from deep in the Grasberg System have been identified that partially homogenise by vapour disappearance at high temperatures (up to 1300°C), well above the hottest measured fumaroles. These inclusions contain 20 – 40 vol.% vapour, three or more transparent crystals and one or two dark to opaque solid phases and less than 10 vol.% water. Are these inclusions with low water contents salt melts? Are the very high temperatures related to magmatic processes or do they represent post-entrapment modification of the inclusions? These scenarios and others will be discussed in this presentation.