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Paper No. 14-12
Presentation Time: 4:30 PM
INVESTIGATING UNUSUAL LAYERED DEPOSITS AT IUS CHASMA, MARS TO CONSTRAIN THE GEOCHEMICAL ALTERATION HISTORY OF THIS REGION OF VALLES MARINERIS
Ius Chasma, located at the western end of Valles Marineris, contains layered outcrops of hydrated materials. Previous analysis of Ius Chasma observed unique surface materials that could be attributed to acidic alteration [1]. Outcrops at Geryon Montes include unusual spectral “doublet” features in CRISM images, which have two bands between 2.2 – 2.3 μm, and vary across the region. Here we analyzed newly developed calibration versions of CRISM images to probe the mineralogy further, including components contributing to the spectral doublet features as well as phyllosilicates found here. We utilized MTRDR images that include joined S and L image data and reduced spectral noise to provide improved spectra across the region 0.4 to 3.9 µm [2], as well as a new algorithm employing simultaneous atmospheric correction and denoising that results in superior spectra of the surface from 1-2.6 µm [3]. Spectra collected from both methods were compared, verifying the integrity of both processing methods. Further, we employed a new feature extracting algorithm [4] based on Generative Adversarial Networks to identify locations containing specific spectral signatures that we are matching with lab spectra of expected minerals. We are mapping subtle differences in the “doublet” materials and associated minerals in relation to neighboring outcrops using hyperspectral factors in the feature extraction rather than just one band, ratio, or slope in the spectrum. This study aimed to characterize the spectral doublet features identified in the Geryon Montes outcrop in relation to mixtures of hydrated silica and phyllosilicates with sulfate minerals, including jarosite and gypsum, that could be forming through aqueous alteration of volcanic ash in the wall rock [5-6]. Characterizing the stratigraphy of these salty components in relation to phyllosilicates and hydrated silica will allow for improved understanding of the changing geochemical environments in which they formed.
References:
[1] Roach L.H. et al. (2010) Icarus, 206, 253-268.
[2] Seelos F.P. et al. (2016) 47th LPSC, Abs. #1783.
[3] Itoh Y. & Parente M. (2019) 50th LPSC, Abs. #2025.
[4] Saranathan A.M. & Parente M. (2019) 50th LPSC, Abs. #2698.
[5] Weitz C.M. et al. (2019) 9th Int’l Mars Conf., Abs #6240.
[6] Bishop J.L. et al. (2020) IEEE IGARSS, Abs. #1502.