effectsofshockmetamorphism
Joseph MichalskiNASA Mars Fundamental Research ProgramEffects of Shock Metamorphism on Phyllosilicate SpectroscopyPhyllosilicates detected on Mars using visible/near infrared (VNIR) spectroscopy clearly point to a history of aqueous alteration with obvious relevance to understanding climate change, evolution of the martian crust, and past habitability of the planet. It is well known that the surface of Mars has been intensely modified by meteor impact, and there is little doubt that many or most of the phyllosilicates detected have experienced some shock effects related to impact. Understanding these effects is critical to the correct interpretation of spectral signatures of martian phyllosilicates, and could illuminate several existing contradictions in the perception of alteration mineralogy on Mars from different instruments.
In this work, we will characterize the effects of experimental shock metamorphism on phyllosilicate mineralogy using VNIR reflectance spectroscopy, thermal infrared emission spectroscopy (TIR), attenuated total reflectance spectroscopy (ATR), X-ray diffraction (XRD), Mössbauer spectroscopy, and transmission electron microscopy (TEM). The combination of these techniques will show how modification of the crystal structure or phase transition induced by shock is manifested in various analysis techniques directly relevant to measurements that have been made at Mars and will be made by future missions. The results of this work will: 1) feed into extremely detailed interpretations of the shapes and positions of spectral bands of phyllosilicates from the Compact Reconnaissaince Imaging Spectrometer for Mars (CRISM) and the Observatoire pour la Mineralogie, l¿Eau, les Glaces, et l¿Activité (OMEGA) data, 2) help illuminate the existing conflict between VNIR and TIR perceptions of phyllosilicate alteration on Mars, 3) show whether rocks discovered by the Spirit Rover in the Columbia Hills region, which have the chemistry of extremely altered materials but spectral features of glass, could be shocked phyllosilicate deposits, and 4) illustrate the effects of shock on XRD data of phyllosilicates, which will benefit the upcoming Mars Science Laboratory (MSL) mission that will investigate phyllosilicate deposits on the ground with XRD.
In this work, we will characterize the effects of experimental shock metamorphism on phyllosilicate mineralogy using VNIR reflectance spectroscopy, thermal infrared emission spectroscopy (TIR), attenuated total reflectance spectroscopy (ATR), X-ray diffraction (XRD), Mössbauer spectroscopy, and transmission electron microscopy (TEM). The combination of these techniques will show how modification of the crystal structure or phase transition induced by shock is manifested in various analysis techniques directly relevant to measurements that have been made at Mars and will be made by future missions. The results of this work will: 1) feed into extremely detailed interpretations of the shapes and positions of spectral bands of phyllosilicates from the Compact Reconnaissaince Imaging Spectrometer for Mars (CRISM) and the Observatoire pour la Mineralogie, l¿Eau, les Glaces, et l¿Activité (OMEGA) data, 2) help illuminate the existing conflict between VNIR and TIR perceptions of phyllosilicate alteration on Mars, 3) show whether rocks discovered by the Spirit Rover in the Columbia Hills region, which have the chemistry of extremely altered materials but spectral features of glass, could be shocked phyllosilicate deposits, and 4) illustrate the effects of shock on XRD data of phyllosilicates, which will benefit the upcoming Mars Science Laboratory (MSL) mission that will investigate phyllosilicate deposits on the ground with XRD.
