ChemCam investigation of the John Klein and Cumberland drill holes and tailings, Gale crater, Mars

• Published in: Icarus
• Main Authors: Jackson, R. S., Wiens, R. C., Vaniman, D. T., Beegle, L., Gasnault, O., Newsom, H. E., Maurice, S., Meslin, P. -Y., Clegg, S., Cousin, A., Schröder, S., Williams, J. M.
• Other Authors: Institut de recherche en astrophysique et planétologie (IRAP), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales Toulouse (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales Toulouse (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France-Centre National de la Recherche Scientifique (CNRS)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2016
• Subjects: Experimental techniques; Mars; surface; [SDU]Sciences of the Universe [physics]; Yellowknife
• Online Access: https://insu.hal.science/insu-03669422; https://doi.org/10.1016/j.icarus.2016.04.026

International audience The ChemCam instrument on the Mars Science Laboratory rover analyzed the rock surface, drill hole walls, tailings, and unprocessed and sieved dump piles to investigate chemical variations with depth in the first two martian drill holes and possible fractionation or segregation effects of the drilling and sample processing. The drill sites are both in Sheepbed Mudstone, the lowest exposed member of the Yellowknife Bay formation. Yellowknife Bay is composed of detrital basaltic materials in addition to clay minerals and an amorphous component. The drill tailings are a mixture of basaltic sediments and diagenetic material like calcium sulfate veins, while the shots on the drill site surface and walls of the drill holes are closer to those pure end members. The sediment dumped from the sample acquisition, processing, and handling subsystem is of similar composition to the tailings; however, due to the specifics of the drilling process the tailings and dump piles come from different depths within the hole. This allows the ChemCam instrument to analyze samples representing the bulk composition from different depths. On the pre-drill surfaces, the Cumberland site has a greater amount of CaO and evidence for calcium sulfate veins, than the John Klein site. However, John Klein has a greater amount of calcium sulfate veins below the surface, as seen in mapping, drill hole wall analysis, and observations in the drill tailings and dump pile. In addition, the Cumberland site does not have any evidence of variations in bulk composition with depth down the drill hole, while the John Klein site has evidence for a greater amount of CaO (calcium sulfates) in the top portion of the hole compared to the middle section of the hole, where the drill sample was collected.