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Charlotte Weinstein
Department of Earth and Planetary Sciences
Washington University in St. Louis
Advisor: Frederic Moynier
Abstract
The ultimate purpose of this project is to understand the process of metal/silicate differentiation in asteroids and on Earth. This will be achieved by measuring the Cu isotopic composition of iron meteorites. Since it is impossible to sample the terrestrial core, iron meteorites, which are pieces of the cores of asteroids, serve as the next best alternative. Samples of these meteorites can be analyzed in order to understand the composition of the core and how planetary bodies differentiate. However, since these samples are so precious, the past year was spent practicing lab technique on more readily available terrestrial samples. This has developed into a side project to investigate the Cu isotopic fractionation associated with the uptake of Cu by living organisms. As a result, we report the Cu isotopic compositions of different components (seeds, germinated seeds, leaves, and stems) of the dicot, lentil (Lens culinaris), and of two monocots, Virginia wild rye (Elymus virginicus) and hairy-leaved sedge (Carex hirsutella). According to our data, the isotopic compositions of these plants are systematically enriched in the lighter isotope of Cu (63CCu) in comparison to the soil in which they grow. Furthermore, different components within the plants themselves are isotopically fractionated. The shoots (stems, leaves and seeds) are systematically lighter than the other parts of the plants and the Cu isotopic compositions of individual leaves correlate with their heights on the plant. This characteristic fractionation in favor of the lighter Cu isotope can be useful in tracing the presence and influence of living organisms in rocks and suggests that Cu could be a tracer of early life in the rock record.
Charlotte Weinstein is originally from Fort Washington, PA. She is currently a sophomore undergraduate student in the School of Arts and Sciences at Washington University in St. Louis. Charlotte plans to study both Earth and Planetary Sciences and Anthropology, with a general interest in geoarchaeology.
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