Characterization of Mars Analog Rocks on Kauai and their Potential Applications to Mars

Abstract

The prospect of life outside the planet Earth has roused interest in humans since the dawn of time. When space exploration began, Mars became the focal point to answering the question, “Could there have been life on Mars?” The answer lies in what most people know as the ultimate requirement for life: water. Mars is thought to have had liquid water four billion years ago during the Noachian period. Clay minerals are one of the indicators for liquid water on Mars and may provide insights into the surface or subsurface geochemical environment that formed them. Alteration of basaltic material leads to the formation of clays, and this process may have occurred on Mars. Using volcanic rocks collected from Kauai, Hawai’i, as an analog, this study involves characterization of altered basaltic material in the hopes of obtaining more information about the alteration of rocks on Mars. Seven samples were collected along the Koke’e Trail in Waimea in April 2009. In the lab, multiple size fractions were prepared for each sample by either dry-sieving or by grinding and dry-sieving, and reflectance spectroscopy was used to investigate changes in the mineralogy. Spectral analysis included determination of band centers and band depths for multiple features due to iron (Fe), hydroxide (OH), and water (H2O) species in the mineral structure. Semi-quantitative analyses were performed to determine the relative abundances of basalt and alteration products in each sample. The samples collected contained olivine, ilmenite, goethite, hematite, maghemite, and phyllosilicates, such as kaolinite and halloysite. These analyses are providing information on how alteration occurred on Kauai, specifically the types of clay minerals present in the Waimea samples. The spectral data generated here will contribute towards understanding the clays observed on Mars by comparing them with spectra taken using CRISM (Compact Reconnaissance Imaging Spectrometer for Mars). CRISM collects visible/near-infrared reflectance spectra at eighteen meters per pixel spatial resolution and is mapping outcrops of clays and other hydrated minerals on Mars. These ancient clay-rich rocks could be indicators for environments where liquid water was once present and that could have been supportive of life.