Samples from the Rocknest aeolian deposit were heated to ~835°C under helium flow and evolved gases analyzed by Curiosity’s Sample Analysis at Mars instrument suite. H2O, SO2, CO2, and O2 were the major gases released. Water abundance (1.5 to 3 weight percent) and release temperature suggest that H2O is bound within an amorphous component of the sample. Decomposition of fine-grained Fe or Mg carbonate is the likely source of much of the evolved CO2. Evolved O2 is coincident with the release of Cl, suggesting that oxygen is produced from thermal decomposition of an oxychloride compound. Elevated δD values are consistent with recent atmospheric exchange. Carbon isotopes indicate multiple carbon sources in the fines. Several simple organic compounds were detected, but they are not definitively martian in origin.
Acknowledgments: NASA provided support for the development and operation of SAM, and for the SAM Science Team, led out of NASA’s Goddard Space Flight Center. The GC-TCD subsystem for SAM was developed in France, with the support of CNES. The TLS subsystem for SAM was developed at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with NASA. Data
from the SAM experiment are archived in the Planetary Data System (pds.nasa.gov). The SAM development, operations, and testbed teams provided essential contributions to the successful operation of SAM on Mars and the acquisition of these data.