Project title: Compositional heterogeneity of the Earth's convecting mantle: Constraints from olivine hosted melt inclusions from a continental-flood basalt setting

Supervisors: Sally Gibson and John Maclennan

The sublithospheric-mantle has long been thought to be heterogeneous; signals observed in the isotopic and trace-element compositions of mantle-derived melts may relate to underlying lithological heterogeneity, which in turn must derive from geodynamic processes such as subduction and delamination.

Melt inclusions in olivine are preserved in quasi-closed system and should record any heterogeneity present in a mantle-derived melt prior to combined mixing and crystallisation processes, so are potentially more useful in investigating the nature of mantle heterogeneity than whole rock samples.

My project looks at picrite and rare ferropicrite samples from the Etendeka province in Namibia (part of the Paraná-Etendeka large Igneous province). A thick continental lithosphere should restrict melting to greater depths, emphasising any fusible material in the source. However, the slow-cooled nature of the samples means that additional steps must be taken to prepare the melt inclusions for analysis - they must be re-melted in a gas-mixing furnace, mounted and polished, for analysis by EPMA, LA-ICPMS and SIMS.

Olivine-hosted melt inclusions from Horingbaai picrites

Publications: 2006-Present

Last updated on 13-Jul-12 12:07