Spectral and Chemical Characterization of Allophane and Imogolite

Allophane and imogolite are nanophase hydrous aluminosilicate clay minerals. Their presence on Mars indicates a time when the presence of water was intermittent and likely short lived. Characterization of these materials has been difficult due to their amorphous characteristics and lack of long range crystallographic order. Fe-K Edge X-ray absorption spectroscopy, 29Si and 27Al Nuclear Magnetic resonance, Fourier transformed infrared spectroscopy, electron microscopy, and emission spectroscopy are used to gain insight on the spectral and chemical properties of these minerals. By using these combination of techniques a dichotomy of allophane species can be resolved, dependent upon Al:Si ratio. Additional insight is gained into the techniques that should be used, given a sample return mission from Mars.masters, M.S., Geology -- University of Idaho - College of Graduate Studies, 2018-0