Dausend, Lonnie

Title:
Interpreting the Mid-Infrared Spectra of the Fine-Grained Allende Meteorite Mixed with KBr

Abstract:
The fall of the Allende meteorite in 1969 proved to be a historic landmark in planetary science for decades to come. The information extracted from Allende enabled scientists to further understand the Solar System formation process and even allowed for the first radiogenic estimate for the age of the Solar System. So, studying this meteorite will allow us to learn more about the early Solar System. To start, we ground a sample of Allende into three particle sizes (0-20 μm, 20-45 μm, 45-63 μm) and mixed each bin with varying percentages of potassium bromide (KBr) to simulate porosity. We then analysed the mid-infrared (5-25 μm) reflectance spectra of each sample using a Fourier Transform Infrared (FTIR) spectrometer.

Spectral analysis of the 0-20 μm Allende powder at 0% - 20% KBr mixtures reveal much stronger spectral features when compared the rest of the samples, and our goal is to figure out the cause. Preliminary analysis indicates that these features can be a result of the particles being closely packed together. To confirm this, we calculated the porosity for each sample and found that the samples creating those strong features have rather low porosities, which is an indication of packing. Therefore, we conclude that the samples that produce those strong features consist of very packed fine-grains. This research sets the groundwork for simulating the Allende meteorite and reproducing its spectra with simulants in a laboratory.

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