MINERALOGICAL SURVEY AND MAPPING OF NORTHERN IANI CHAOS

MARIA CAROLINA ROJAS; MAURO GABRIEL SPAGNUOLO; MARA MANTEGAZZA; HERNÁN PABLO BARCELONA; ANGELO PIO ROSSI

Encuentro; The Annual Meeting of the Planetary Geologic Mappers; 2022

MINERALOGICAL SURVEY AND MAPPING OF NORTHERN IANI CHAOS. M. C. Rojas1, M. G. Spagnuolo1, M. Mantegazza1, H. Barcelona1, A. Pio Rossi2. 1Instituto de Estudios Andinos “Don Pablo Groeber”, University of Buenos Aires, Argentina. 2 Department of Germany.Introduction: Chaotic terrains on Mars are partially enclosed basins surrounded by extensional fractured and eroded highlands, whose origin is considered the result of different processes that could have triggered massive release of groundwater onto the surface and subsequent collapse of the surface [e.g. 1,[2].In particular, Iani Chaos is a main example of morphologically complex chaotic terrain (Figure 1a), this area is located in the east of Valles Marineris, at the northern margin of Margaritifer Terra and at the head of Ares Vallis, on Mars, centered at 2.0°N, 342.2°E.In this work, we focused the analysis on a northern region of Iani Chaos (Figure 1b). The area is characterized by chaotic terrain morphology, knobby terrain, mesas, fractures, and Light Toned Layered Deposits generally in the lower parts, as well as aeolian deposits.Within this mapping study we also investigated the presence of hydrated minerals using hyperspectral data combined with high resolution images. We produced a preliminary map to investigate the hypothesis of a possible geothermal system in this region. To this end, we focused in the search of hydrated minerals that could be formed by the interaction between groundwater in a low temperature geothermal system.Data and methods: A survey of north region of Iani Chaos was made based on CTX-Mosaic images (from Global CTX Mosaic of The Bruce Murray Laboratory for Planetary Visualization: CTX-Mosaic_beta01_E- 018_N-02, CTX-Mosaic_beta01_E-018_N-04), with a resolution of 6 meters per pixel. A map is being produced using open-source software QGIS.We analyzed a CRISM image using CAT (CRISM Analysis Toolkit extension for ENVI). We used the Map-Projected Targeted Reduced Data Record (MTRDR) (FRT000134d2) and its derived summary product CRISM cubes to identify/interpret mineral composition [e.g. 3].The CRISM analysis consisted in processing the hyperspectral images using different bands combination and indexes to highlight geologic features. In particular, we considered the index combination that provided an inference of hydrated minerals or hydrated sulfates based on the literature [e.g. 2].We applied several RGB combination of different summary products. For instance: i) FAL (R:R2529, G:R1506, B: R1080), enhances false colour representation of the scene, ii) HYD (R: SINDEX2, G: BD2100_2, B: BD1900_2) that points out hydratePhysics and Earth Sciences, Jacobs University Bremen,minerals such as, polyhydrated sulfates; iii) PHY (R: D2300, G: D2200, B: BD1900r2) shows information related to hydroxylated minerals including phyllosilicates, (e.g., Fe/Mg-phyllosilicates, Al- phyllosilicates or hydrated silica) or other hydrated minerals (such as sulfates, hydrated silica, carbonate, or water ice) and iv) PFM (R: BD2355, G: D2300, B: BD2290) that indicates cation composition of hydroxylated minerals including Fe/Mg-phyllosilicate [e.g. 4].Figure 1: CTX Mosaic of Iani Chaos. In light-blue the CRISM location (FRT000134d2_07_if165_mtr3). In lilac HiRISE images location (ESP_012438_1795 and ESP_013572_1795). Results: First, infrared false color scene is showing a mineralogical variation between the Light TonedPlanetary Geologic Mappers 2022 (LPI Contrib. No. 2684)7020.pdfDeposits and the surrounding bedrock and was a base image to map different target zones. (Fig. 2a).Fig. 2b shows HYD RGB composition. In the south and in the eastern margin of the Crism image, a magenta signal that coincides with a Light Toned Layered Deposits, this could be indicating polyhydrated sulfates. Other zones have a blue color that indicates the presence of generic hydrate minerals.Fig. 2c shows PFM RGB composition. Here a small area is highlighted with cyan color suggesting the presence of Fe/Mg smectites or Mg carbonate.Finally, using the PHY RGB composition (Fig 2d) the same region in the western margin shows magenta colors pointing out Fe/Mg phyllosilicates and ruling out carbonates. And there are other zones (3 and 4) that show cyan color indicating Al-phyllosilicates or hydrated silica.Lastly, we inferred the presence of hydrate sulfates, and other hydrate minerals such as Mg/Fe phyllosilicates. In particular, LTD have a distinct sulfate signal and zone 2 seems to be rich in Fe/Mg phyllosilicate. For future works, we would intend to analyze spectral profiles from the different zones in order to support mineral composition and determine the presence of gypsum or another hydrate sulfate; considering the aim to create a geomorphologic map of this region.Figure 2: FRT000134d2_07_su165j_mtr3. a) Falsecolor. b) HYD RGB combination magenta color indicates polyhydrated sulfates, blue indicates other hydrate minerals. c) PFM, cyan color indicates the presence of Fe/Mg smectites or Mg carbonate. d) PHY, hydrated Fe/Mg-phyllosilicates appear, hydrated Al- phyllosilicates appear in cyan.Acknowledgments: The HiRISE, CTX and CRISM images were obtained from Planetary System Data (PDS). This work was possible to fund of the project PICT-2019-01796, to be acknowledge to the GMAP (Geologic Mapping of Planetary bodies) group.References: [1] Rodriguez, et al. (2005a), Icarus, 175(1), 36–57. [2] Warner, N. H., S., et al. (2011), JGR, 116, E06003. [3] Luzzi, E., et al. (2020), JGR Planets, 125, e2019JE006341. [4] Viviano-Beck, C. E., et al. (2014), JGR. Planets, 119, 1403–1431.