The 2008 Outstanding Young Scientist Award is awarded to Maud Boyet for successfully unlocking geochemical secrets of the Earth’s early mantle development and evolution by 142Nd.
Maud Boyet uses remarkable analytical skills to measure differences of tens of ppm in the neodymium isotope ratio 142Nd/144Nd to produce the best evidence yet that the composition of the Earth was irreversibly modified by chemical differentiation events that occurred within a few tens of million years of solar system formation. 142Nd is created by the decay of 103 Ma half-life 146Sm. Maud began her 142Nd studies using the multi-collector ICP-MS. At the time, no one had achieved sufficient precision with the MC-ICP-MS to perform such measurements. Through very careful analyses, Maud was able to resolve excesses in 142Nd in a small group of rocks from Isua, Greenland (EPSL, 2003), and thereby prove that chemical differentiation had occurred on Earth while 146Sm was still alive. Maud then showed by difficult analyses of low Nd content chondritic meteorites that all rocks from the Earth have higher 142Nd/144Nd compared to a wide variety of meteorites. She used this discovery to argue for an early magma-ocean differentiation of the silicate earth that left the majority of the mantle depleted in incompatible elements (Science, 2005). The importance of this discovery is marked by its selection as one of the top ten “Science Breakthroughs of 2005” by Science magazine. As she expounded in both the Science paper and in the more detailed modeling contained in a later paper (EPSL, 2006), this result has major implications for wide-ranging issues such as the composition of the mantle source of ocean ridge volcanism, the conventional model for the relationship between continental crust formation and mantle depletion, long-term mantle dynamics, atmospheric composition, and possibly the history of Earth’s liquid outer core and magnetic field. Maud’s discovery, and her discussion of the significance of the result in her papers published in Science and EPSL, highlight the ever increasing evidence that events occurring shortly after planet formation have a lasting, if not dominant, effect on the geochemical and geodynamic evolution of the terrestrial planets.