Flora Nicholls

Understanding the composition of the Earth’s mantle is fundamental to models of mantle convection, plume dynamics, volcanism, seismicity and long-term planetary evolution. Despite this, major questions about the character of the mantle remain unanswered, such as whether the mantle consists of a single uniform (but chemically diverse) lithology (rock-type), or multiple distinct lithologies. Trace element and radiogenic isotope systematics of lavas erupted from deep mantle plumes clearly demonstrate that the mantle is geochemically heterogeneous, but the processes which vary these compositions are not necessarily directly related to mantle lithological heterogeneity. Stable isotope compositions, however, vary due to differences in bond strength between hosting minerals, and may therefore reflecting their source lithology. My research combines classic radiogenic isotope tracers (Sr, Nd, Hf, Pb) with developing novel stable isotopes systems (V, Fe, Zn) to simultaneously investigate mantle chemistry and lithology, providing a direct approach for tracing lithological heterogeneity in mantle-derived melts.