EAR-PF: Windows into Ancient Impacts: Examining Meteoritics Research with New Approaches

Sims, Melissa, Baltimore MD

Investigators

Abstract

Dr. Melissa Sims has been granted an NSF EAR Postdoctoral Fellowship to carry out research and education activities at Johns Hopkins University under the mentorship of Professors June Wicks and Sabine Stanley and at Lawrence Livermore National Laboratory guided by Dr. Minta Akin. The research will focus on understanding meteor impacts and subsequent cratering; as these processes played an important role in the formation and evolution of the Earth. Dr. Sims will conduct a series of 10 high-pressure shock experiments aided by in-situ X-ray diffraction and imagining techniques to better understand of deformation mechanisms and phase transition kinetics in shocked olivine and plagioclase. These minerals are important igneous minerals in the Earth and other rocky planetary bodies. Additionally, impact processes are relevant to national defense, which is another of the broader impacts of this project. Dr. Sims will mentor undergraduate students at minority serving institutions where she will also serve as a role model. The project will use high pressure experiments to investigate the conditions under which buried or eroded craters are formed. This information often lost subsequent to impacts due to erosion or weathering. The ultimate goal of this proposal is to produce a more complete picture of natural shock processes. Dr. Sims will examine shock on experimental timescales and extrapolate the types and extent of mineral transformations which are possible on natural timescales. This project will complete two types of experiments, rapid compression using diamond anvil cells and shock experiments using gas guns. New analytical tools have recently become available to investigate shock processes in-situ. Dr. Sims will apply diffraction and scattering analysis to identify the deformation and phase transformation processes that occur during the experiments. By varying experimental conditions, such as peak pressure and temperature, it is possible to understand natural events. The research will be completed with the assistance of undergraduate students from a minority-serving institution who will be involved with experiments at national laboratory facilities. This project received funding from the Geophysics and the Geochemistry and Petrology programs in the Earth Science division. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.