• Caravaca, Gwénaël
• Horgan, Briony
• Núñez, Jorge
• Sholes, Steven F.
• Bell, James F.
• Kah, Linda C.
• Ives, Libby R. W.
• Schmitz, Nicole
• Williams, Rebecca M. E.
• Bechtold, Andreas
• Ortner, Thomas
• Traxler, Christoph
• Stack, Kathryn M.
• Barnes, Robert
• Gupta, Sanjeev
• Paar, Gerhard
• Lesh, Conner
• Kanine, Oak A.
• Tate, Christian
• Tebolt, Michelle
• Annex, Andrew M.

Abstract

The NASA Mars2020 rover Perseverance traversed series that represent the transition from crater floor lithologies to deposits of the Jezero western fan during its second Earth year of rover operations. During that time, the mission explored the exposed stratigraphic succession at the delta front, named the Shenandoah formation. The main science camera on the rover, Mastcam-Z, collects stereo-images of outcrops encountered in visible to near infrared wavelengths at focal lengths ranging from 34 to 110 mm. We use the Planetary Robotics Vision Processing and Planetary Robotics 3-D Viewer tools (PRoViP and PRo3D respectively) for processing, viewing and analysing correctly scaled and located 3-D digital outcrop models using Mastcam-Z stereo-images. Scaling and georeferencing of the models is achieved by incorporation of detailed camera models, image metadata detailing the camera pointing azimuths, focus, exposure and rover attititude, and spatial metadata obtained through incorporation and conversion of SPICE kernels. We can visualise these digital outcrop datasets overlain on high resolution orbital terrain data to measure the geometry of geological bodies and correlate observations between rover positions. Four cross-sections were constructed across the lower delta stratigraphy at the base of Hawksbill Gap and Cape Nukshak using data collected from 3D reconstructions of Mastcam-Z stereo-images and HiRISE topography. Lithological observations made from Mastcam-Z image mosaics were used to inform interpretations on multiple 3D reconstructions of stereo-image data. Stratigraphic boundaries based on team analyses, and the key dip and dip azimuth measurements, were mapped in PRo3D and plotted on topographic profiles to visualise the depositional architecture. Stratigraphic thicknesses were corrected for dip, where necessary, to build stratigraphic logs. The basal surfaces of the identified members which comprise the Shenandoah formation were correlated between the lines of section to illustrate the architectural variations across the delta front.We show that the overall boundaries of the stratigraphic units identified are sub-horizontal at the 100s of metre scale but show considerable variation in some locations at the sub-metre scale, largely as a result of soft sediment deformation, and the limited development of scours and low angle cross-stratification.

Topics

• impedance spectroscopy
• surface