Evolution of Clay Minerals on the Surface of Mars

1. Evolution of Clay Minerals on the Surface of Mars • Introduction • Clays • Oldest material that are products of interactions with water (Poulet et al., 2005) • May be responsible for Mars’ red color (Weldon et al., 1982) • Can support organic material Clays Future Experiments In the Andromeda Vacuum Chamber: • We first want to replicate previous experiments and compare the results, then conduct new ones. We will do two experiments in the Chamber: • Record the desorption rate of water through a layer of wet clay. • 2. Measure the sublimation rate of ice under a layer of clay. • Both of these experiments will be conducted in martian atmospheric conditions, with varying temperatures. Hydrological Experiments Figure 1: The blue area maps out where aluminum-rich clays are found. (Image taken from Poulet et al., 2005.) In the High-Temperature Ovens: This sample of montmorillonite was placed in a desiccator over night so that it absorbed as much water as possible. Then we heated it to 50oC, and weighed it at regular intervals. We found a correlation of time heated with mass loss. This mass loss is due to the loss of absorbed water in the montmorillonite. • We will, again, replicate previous experiments, then conduct new ones. • Heat one-gram samples of different types of clays to 750oC to 1000oC, and compare results to those of previous experiments. These experiments will be conducted in air (Earth atmosphere). • Heat one-gram samples to the same temperatures in CO2. This experiment has never been done before and is anticipated to give interesting results. Figure 2: (a) and (b) are infrared images taken by THEMIS. (c) and (d) are enlarged optical images taken by the Mars Orbiter Camera. The blue area is a superimposed map of iron-rich clays. Lava appears brighter in infrared than the surrounding clays due to its higher temperature, a result of its lower albedo. (Image taken from Poulet et al., 2005.) MineralogicalExperiments (a) (b) Acknowledgements • Dr. Vincent Chevrier – Mentor, for his guidance through these experiments • Walter Graupner - Lab Manager, for finding all the right parts and helping us assemble those parts for each experiment • University of Arkansas – for allowing us to use their superior facilities in conducting these experiments Figure 3: Nili Fossae (Images taken from Mustard et al., 2006.) (a) Green – Low-Calcium pyroxene Blue – Phyllosilicates Pink – Olivine (b) “O” indicates location of olivine-bearing rocks Figure 4: Two samples of nontronite. The samples on the left are non-treated nontronite. The sample on the right in the upper image was heated in air to 750oC for 6 hours. The sample on the right in the lower image was heated in air to 1000oC for 6 hours. Note the color change as the clay’s molecular structure changes during heating. Patricia Gavin – Florida Institute of Technology Dr. Vincent Chevrier – University of Arkansas