Mantle dynamics and the noble gas isotopic composition of oceanic island basalts (OIBs)

The isotopic variability observed in OIBs from individual mantle plume regions is usually related to mixing processes in the mantle and thus interpreted in terms of sampling different mantle reservoirs. Little is known about the contribution of magmatic processes in mantle plumes to those heterogeneities. Without an understanding of these processes and their contribution to geochemical parameters it is difficult to accurately explain the composition, evolution and formation of the Earth’s mantle. Thus this project is concerned with the detailed study of the noble gas isotope composition of fresh, submarine basaltic glasses from the Easter and Foundation plumes in order to resolve: (1) the spatial distribution of plume material, (2) the magmatic and mantle dynamic processes in the plumes and (3) the compositions and developments of mantle sources. Both hotspots have variable compositions ranging from MORB-like to enriched basalts with high ^₈₇Sr/⁸⁶Sr and ²⁰⁶Pb/²⁰⁴Pb, indicating that both, different mantle sources and melting processes contribute to magma genesis. Noble gas isotopes are, caused by their physico-chemical properties one of the best tracers for modelling mantle processes.

 

• Contact:  Dr. Nicole Stroncik