Fresnel modeling of hematite crystal surfaces and application to martian hematite spherules |
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| Authors: | Timothy D Glotch Philip R Christensen Thomas G Sharp |
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| Institution: | Department of Geological Sciences, Arizona State University, Tempe, AZ 85287, USA |
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| Abstract: | The gray crystalline hematite at Meridiani Planum first discovered by the Mars Global Surveyor Thermal Emission Spectrometer (MGS-TES) instrument occurs as spherules that have been interpreted as concretions. Analysis of the TES and mini-TES spectra shows that no 390 cm−1 feature is present in the characteristic martian hematite spectrum. Here, we incorporate the mid-IR optical constants of hematite into a simple Fresnel reflectance model to understand the effect of emission angle and crystal morphology on the presence or absence of the 390 cm−1 feature in an IR hematite spectrum. Based on the results we offer two models for the internal structure of the martian hematite spherules. |
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| Keywords: | Infrared observations Mars surface Mineralogy Spectroscopy |
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