Goals and objectives background: over the past decade, the planetary science community has found abundant evidence of ancient low-temperature aqueous environments and processes on mars. Much of that…

This is a five-year grant award from the National Aeronautics and Space Administration (NASA) to Bryn Mawr College for $112,849.81. The grant is focused on refining capabilities to assess the mineralogy of the Martian surface using visible and near-infrared (VNIR) spectroscopy data from NASA's Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) instrument. The research aims to better understand how mixtures of iron oxyhydroxides and iron sulfate minerals on Mars can impact the interpretation of VNIR spectra and the assessment of past aqueous environments on the planet. The research will involve analyzing laboratory-prepared mineral mixtures and natural samples from analog environments on Earth, and comparing the results to CRISM data from Mars. This work is intended to enhance the scientific returns from the CRISM instrument and support future Mars exploration and landing site selection.

Goals and objectives background: over the past decade, the planetary science community has found abundant evidence of ancient low-temperature aqueous environments and processes on mars. Much of that evidence has come from visible to near-infrared (VNIR) spectroscopy. By comparing the minerals detected by VNIR spectroscopy to terrestrial environments in which these minerals form, we start to understand the range of past aqueous environments that existed on mars. However, one of the major limitations of VNIR spectroscopy is how IT responds to mixtures of minerals. Minerals with strong optical constants can obscure the VNIR signatures of minerals with weak constants, even if the second mineral exists in much greater abundance. This spectral masking effect can complicate the interpretation of environmental conditions on mars, because key mineral assemblages can be obscured. An important example of this is the case of iron-bearing oxyhydroxides and sulfates, which have been identified at several locations on the martian surface, and are often used as markers of liquid water and environmental conditions. However, environmental interpretations on the basis of hydrated iron minerals are only useful to the extent that we can estimate their abundance and distribution in geologic and geographic context. Because they form in similar environments and often are products of each other they likely occur on mars in mixtures, making IT important for US to understand the spectral appearance of mixtures of iron oxide and iron sulfate minerals in the VNIR. Here, we propose to study to measure the impact of mixtures on the VNIR spectra of iron oxyhydroxides and on VNIR spectra from mars. Objective: refine capabilities to assess mineralogy of martian VNIR spectra in terms of mixtures of iron oxyhydroxides and iron sulfate minerals. Methodology: VNIR spectra from NASA's satellite-borne compact reconnaissance imaging spectrometer for mars (CRISM) will be compared to spectra of laboratory mixtures of iron oxyhydroxides and iron sulfates, and to natural samples. The laboratory mixtures will be prepared and analyzed with a VNIR spectrometer and X-RAY diffractometer, with the goal of identifying the composition at which a mineral (X) will spectrally mask another (Y). Once the composition at which X is masked in an XY mixture is determined, then grain sizes of X will be varied in the mixtures to assess the impact of grain size on spectral masking. Mixtures will be compared to field samples already obtained from acid mine drainage systems in southeastern pennsylvania and RIO tinto, spain. Finally, the laboratory mixtures and natural samples will be compared to CRISM spectra from mars over areas previously mapped as having iron oxyhydroxides and iron sulfates. Relevance: the proposed study is relevant to mdap, as IT focuses on enhancing the returns from the CRISM instrument aboard mars reconnaissance orbiter (MRO). We propose to analyze publicly-released data from the CRISM instrument. Specifically, this program will involve, "analysis and comparison of mars orbital and surface data to increase the predictive accuracy of surface characteristics of mars from orbit." significance: this work will allow other mars researchers to more accurately describe the mineralogy of complex sites on mars, including potential new landing sites for future missions. Additionally, IT will continue the work of linking terrestrial and martian low temperature geochemical processes, and of using earth analog environments to understand past environments on mars.