Investigating the mineralogical composition of Martian crater and intercrater deposits in Meridiani Planum using CRISM spectral data

Meridiani Planum is a plain on Mars located near the equator south west of Arabia Terra. Its southern part was studied for about 14 years by the MER Opportunity rover, which landed on the 25th of January 2004. The rover detected hydrated and water altered minerals such as sulfates, phyllosilicates and hematite spherules. Other than the presence of hydrated minerals, Meridiani Planum harbors morphological features related to water erosion such as valley networks that cut the oldest units of this region, and most importantly, it hosts a thick sequence of sediments rich in hydrated minerals, which were deposited at the boundary between the Noachian and the Hesperian epochs. During this transition Mars evolved from being a warm and wet planet to the cold and dry place it is today. On the 10th of March 2006 the Mars Reconnaissance orbiter successfully entered orbit around Mars carrying with it some of the most advanced instruments at our disposal today. Among this instruments the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) permitted the gathering of high resolution reflectance spectroscopy data having resolution of 15-19 m/pixel and bandwidths of 6.55 nm/channel, and together with the High Resolution Imaging Science Experiment (HiRISE), that possesses a peak resolution of 0.3 m/px, and the Context Camera (CTX) provided information and data used in unprecedented discoveries about our neighboring planet. Using CRISM most advanced products called MTRDR we analyzed three regions in Meridiani Planum, the north portion of the Kai crater, and other two areas, located northwest and north of a formation called Piscinas Serpentes, specifically an unnamed small oblique impact crater and a portion of a intercrater formation. To do the analysis we developed an original Python pipeline composed of RGB map generation, spectra extraction, spectra normalization and spectra comparison including three different methods of spectra normalization to enhance the spectral characteristics. We located and identified deposits of hydrated minerals analyzing different regions of interest. In all of the studied regions we have found presence of several sulfates and phyllosilicates mineralogical phases belonging to different geological units. This suggests that the different hydrates minerals were deposited during several separate events, implying a difference in the presence and activity of water in the area during the timespan between late Noachian and early Hesperian. In the first region we have selected 8 different zones of interest in which we have found monohydrated sulfates, polyhydrated sulfates and Al, Mg and Fe smectites in different relative stratigraphic position and elevation. Regarding the second region we have selected 7 zones in which we have found Mg smectite and talc deposits in the crater basin with deposits of monohydrated and polyhydrated sulfates and traces of Al smectite on the outer south rim of the crater. Finally, regarding the intercrater formation we have selected 5 zones in which we have found polyhydrated and monohydrated sulfates, Mg/Fe smectites and talc. Combining the spectral information with Digital Terrain Models from CTX and HiRISE cameras, we can characterise the stratigraphic relationships between the clay and sulfate layers.