The 176Lu-176Hf isotopic system is an invaluable tool for studying early differentiation in the Earth and other planets. The initial condition of this isotopic system in the Earth, a pre-requisite for its accurate use, remains elusive, despite the growing amount of Lu-Hf data on early Solar System materials.
The Lu/Hf ratio, and ratios of other refractory elements, directly measured in chondrites, may not represent the bulk terrestrial and Solar System values, because of chondrite heterogeneity (within a meteorite and between the classes of chondrites), and possible impact erosion or early volcanism.
These complications will be addressed in this project. The student will study the Lu-Hf isotopic system, and U-Pb and Sm-Nd as necessary, in the least metamorphosed chondrites and in chondritic matrices using plasma ionisation mass spectrometry, and explore the correlation between Lu/Hf and the ratios of other refractory lithophile elements in various classes of chondrites and in Solar photosphere.
This project will also involve the first direct measurements of the initial 176Hf/177Hf of the Solar System in minerals with low Lu/Hf ratio (such as ilmenite and zircon) from old, well preserved meteorites.