Ernst Hauber, German Aerospace Center (DLR) (Germany)
Klaus Gwinner, German Aerospace Center (DLR) (Germany)
Maria Hilke, German Aerospace Center (DLR) (Germany)
Frank Preusker, German Aerospace Center (DLR) (Germany)
Ralf Jaumann, German Aerospace Center (DLR) (Germany)
Despite more than three decades of research, the nature of interior layered deposits (ILD) inside the Valles Marineris on Mars is still unknown. Recent spacecraft mission provided images with unprecedented resolution ( about 25-30 cm/pixel; HiRISE), spatially high-resolution topography (HRSC), and mineralogical information (OMEGA, CRISM). One of the most important findings was the association of hydrated sulfates with many, but not all ILD. One theory of ILD formation holds that they formed as subglacial volcanoes, analogous to terrestrial subglacial volcanoes like Herdubreid or to hyaloclastite ridges like Tindaskagi (both in Iceland). We test this theory by a comparison of Mars data with recently acquired data of Icelandic subglacial landforms, taken by the HRSC-AX instrument. HRSC-AX is the airborne version of the High Resolution Stereo Camera (HRSC), which is in orbit around Mars on board the Mars Express mission since 2004. HRSC-AX obtains stereo images with a resolution of about 25 cm/pixel, together with colour information from 4 channels.
These images have a resolution which is almost identical to that of the HiRISE camera. Therefore, we can compare Martian ILD to terrestrial subglacial volcanoes using image data with the same spatial resolution, a situation which is typically not given. Images of Icelandic features were taken in 2006, covering parts of the western volcanic zone. Subglacial features included the table mountain Hrafnabjörg, a subglacial volcano with steep flanks and a flat top, and the hyaloclastite ridges (moberg ridges) of Tindaskai and Kalfstindar, which are characterized by well developed layering on their flanks. We present the results of our photogeologic mapping of Icelandic features, focusing on morphologies which are diagnostic of subglacial volcanism, and compare them to features on Mars visible in HiRISE and other images. We also present quantitative data on the topography of the terrestrial landforms, and compare them to the digital topography data of Martian features from HRSC, and to a qualitative assessment of their extremely high-resolution, but very local topography using HiRISE anaglyph images. The goal is to establish diagnostic criteria that would allow the verification or rejection of the subglacial model for ILD formation, and, therefore, to put constraints on the formation of layered deposits and sulfates on Mars.