B8 - Is the depletion of the moderately volatile elements in the Earth inherited from nebular processes?
All planetary materials are depleted in volatile elements to various degrees, the origin and mechanisms of these depletions are not yet understood. Carbonaceous chondrites, as remnant material of the early stages of planet formation, can be used to help constrain processes in the solar nebular. For some moderately volatile elements in these meteorites, correlations between stable isotope composition and degree of depletion have been observed.
Do these trends also correlate with varying abundances of chondrite components in the different carbonaceous chondrite groups? How do refractory inclusions, the oldest components of these meteorites, contribute to the volatile element budget and stable isotope composition of their bulk rock? In which environment were volatile elements incorporated into these inclusions? Did the processes responsible for these trends take place in the solar nebula, or on the parent body, both? Did planetary materials inherit their volatile element depletions from undifferentiated planetary building materials? If there is a correlation between meteorite component abundances and bulk composition of meteorites, can it potentially be extended to Earth?
We use stable isotope compositions of the volatile metals Zn, Cu, K in individual refractory inclusions to understand the processes affecting the moderately volatile element composition of these components and the environment in which they took place. Electron beam methods provide petrologic context to the geochemical observations by characterizing the mineralogy and textures of the inclusions and the distribution of the elements in question.