Science Report
Melissa Battler
02/06/2013
Today we drove to the final sampling site for my sulfate study, and successfully collected Mancos Shale gypsum samples near the end of Coal Mine Road, in the area known as “Coal Mine Wash”. I sampled both the clear bedding-parallel gypsum veins in the creek, and the slabs of gypsum in the nearby valley formerly referred to as “glass valley” (so called because the gypsum fragments shine in the sun like broken glass). Tonight or tomorrow we will conduct Raman analyses in the MDRS lab to confirm the mineralogy of all of the (assumed) sulfate samples that I’ve collected over the past 10 days. Based on the mineralogy literature for the MDRS area, I hypothesize that all of the white vein and nodular samples are predominantly gypsum, however the compositions of the samples of white efflorescence (salt crusts) collected from the surface of the soil in various locations is unknown, and additional sulfate or halide minerals may be present. These samples will be taken back to Western University where they will be completely analyzed for mineralogy via X-ray Diffraction (XRD), and then I will take them with me to the University of Winnipeg where they will be analyzed via UV-vis-nIR reflectance spectroscopy (definitely over the range of 0.35 to 3.5 microns; possibly up to 25 microns). Laboratory-based spectroscopy results will be a good proxy for Mars orbital spectroscopy data (e.g., CRISM, OMEGA), and this information can then be applied to Mars data in the search for interesting sulfate deposits on Mars. Additionally, laboratory-based spectral results will be compared to Aster spectral data from the MDRS region, to see if any of the sulfate sites I’ve visited are visible from aerial spectra. (unfortunately, we were not able to obtain Aster data before my rotation at MDRS, so we’re doing things a little bit backwards). The resolution of the Landsat data my colleagues and I obtained for the MDRS region is unfortunately too low to see any surficial sulfate deposits, so hopefully the Aster data will be more telling. Finally, because on both Earth and Mars sulfate minerals are: 1. detectable from orbit, 2. require water to form, 3. can protect microorganisms from radiation and oxidizing atmospheric conditions, and 4. are capable of preserving evidence of biological material over a long time scale, they are a good target in the search for evidence of life on Mars. Therefore, hopefully my sulfate samples will also be analysed to determine whether any organic material is present, and quantity/quality of organic content will be compared to that found in clays around MDRS.