Nature and Evolution of the Upper Mantle beneath Heard Island

This project is using ultramafic xenoliths - samples of the mantle beneath Heard Island to study the formation and evolution of the Kerguelen-Heard Plateau. Such plateaus are thought to represent an important stage in the formation of continents over the earths history. Additionally, new evidence suggests the Kerguelen Plateau may contain ancient continental fragments, which are possible remnants of Gondwana.Ultramafic xenoliths were collected from Heard Island during field season 2000 from 6 locations, 5 of which were previously unreported. Petrological and geochemical information is being used to characterise the mantle beneath Heard Island, and Re-Os isotopic dating is being used to constrain the formation age of the plateau. Initial results indicate the mantle beneath Heard Island is highly depleted in basaltic components. The presence of reaction textures containing small amounts of carbonate in some xenoliths is an indication of possible carbonatitic metasomatism, which has been observed for similar samples from Kerguelen.The fields in this dataset are:MU Number (Macquarie University Catalogue Number)Sample NumberLocationLatitudeLongitudeDescription