Investigation of the Glen Torridon Clay-Bearing Unit and Overlying Greenheugh Pediment by the Sample Analysis at Mars Instrument SuiteExploring the Glen Torridon (GT) clay-bearing unit in Gale crater has long been a prime goal for the Mars Science Laboratory (MSL) because of spectral signatures of smectite identified from orbit. Smectite clay minerals can indicate habitable environments [1,2] and possibly facilitate the preservation of organic compounds [e.g., 3-7].Also, sulfate-bearing layers overlie GT and this sequence may record a large-scale change in aqueous conditions overtime [8].The Sample Analysis at Mars (SAM) instrument suitehas been essential in understanding volatile-bearing phases in Gale crater materials. SAM EGA has detected H2O, CO2, O2, H2, SO2, H2S, HCl, NO, and other trace gases, including organic fragments, evolved from many samples on heating. The identity and evolution temperature of evolved gases can support mineral detection by CheMin instrument X-ray diffraction (XRD)and place constraints on trace volatile-bearing phases, clay mineral compositions, and X-ray amorphous materials. In GT, SAM analyzed the sample Kilmarie (KM) from the Jura member, Glen Etive (GE), Mary Anning (MA) and Groken (GR)from the Knockfarril Hill member (KHm), Glasgow (GG) and Hutton (HU) from the fractured Intermediate Unit (fIU), and Edinburgh (EB) from the Stimson formation rocks of the Greenheugh Pediment (GP). The Jura, KHm and fIU are all members of the Murray formation. HU was sampled near the basal Siccar Point group (SPg) unconformity between the fIU and GP, in an area that exhibits a brighter tone and differences in geochemistry compared to Murray materials down-section [9,10]. CheMin XRD of most samples (except for HU and EB)showed large abundances of smectite clay minerals (~25-35%) and all samples showed X-ray amorphous materials and relatively low amounts of well-crystalline hematite[11]. SAM evaluated mineralogy through evolved gas analysis mass spectrometry (EGA) while detailed organic chemistry of several samples was examined by pyrolysis gas chromatography mass spectrometry and wet chemistry experiments [12,13].Here we discuss data and interpretations from SAM EGA analyses.
Document ID
20210012955
Acquisition Source
Johnson Space Center
Document Type
Conference Paper
Authors
A C McAdam (Goddard Space Flight Center Greenbelt, Maryland, United States)
B Sutter (Jacobs (United States) Dallas, Texas, United States)
P D Archer (Jacobs (United States) Dallas, Texas, United States)
H B Franz (Goddard Space Flight Center Greenbelt, Maryland, United States)
J L Eigenbrode (Goddard Space Flight Center Greenbelt, Maryland, United States)
C A Knudson (University of Maryland, College Park College Park, Maryland, United States)
J M T Lewis (Howard University Washington D.C., District of Columbia, United States)
G M Wong (Pennsylvania State University State College, Pennsylvania, United States)
J V Clark (Jacobs (United States) Dallas, Texas, United States)
M. Millan (Georgetown University Washington D.C., District of Columbia, United States)
A. J. Williams (University of Florida Gainesville, Florida, United States)
S. Andrejkovičová (University of Maryland, College Park College Park, Maryland, United States)
C. Freissinet (LATMOS-IPSL)
D P Glavin (Goddard Space Flight Center Greenbelt, Maryland, United States)
J C Stern (Goddard Space Flight Center Greenbelt, Maryland, United States)
R. Navarro-González (Univ Nacional Autonoma de Mexico)
C N Achilles (Goddard Space Flight Center Greenbelt, Maryland, United States)
D W Ming (Johnson Space Center Houston, Texas, United States)
R V Morris (Johnson Space Center Houston, Texas, United States)
T F Bristow (Ames Research Center Mountain View, California, United States)
E B Rampe (Johnson Space Center Houston, Texas, United States)
M. T. Thorpe (Johnson Space Center Houston, Texas, United States)
A. S. Yen (Jet Propulsion Lab La Cañada Flintridge, California, United States)
C. H. House (Pennsylvania State University State College, Pennsylvania, United States)
A B Bryk (University of California, Berkeley Berkeley, California, United States)
V. K. Fox (University of Minnesota Minneapolis, Minnesota, United States)
K. A. Bennett (USGS Astrogeology Science Center)
S. S. Johnson (Georgetown University Washington D.C., District of Columbia, United States)
P. R. Mahaffy (Goddard Space Flight Center Greenbelt, Maryland, United States)
C A Malespin (Goddard Space Flight Center Greenbelt, Maryland, United States)