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THEMIS spectral unit mosaics

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Blackbody distribution represents varying surface spectral contrast due to ... indicating relatively low dust cover compared to classic high-albedo regions ... – PowerPoint PPT presentation

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Title: THEMIS spectral unit mosaics


1
THEMIS spectral unit mosaics
Olivine basalt (0-1.5)
Blackbody (-1 to 1)
RMS Error (0-0.01)
Eberswalde
Data below -1650 m excluded
2
THEMIS spectral endmembers
  • Blackbody distribution represents varying surface
    spectral contrast due to either varying
    contribution from dust or to varying particle
    size/surface texture
  • Olivine basalt surface is similar to TES Surface
    Type 1

Eberswalde
3
TES analysis of THEMIS spectral units
Modeled abundances Olivine Basalt Feldspar 22
/- 4 Pyroxene 28 /- 5 Olivine 12 /- 3
High-silica 25 /- 5 Other 13
High-silica phases silica glass, opal,
zeolite, clay (cannot reliably distinguish these)
Other carbonate, sulfate, hematite,
amphibole, quartz (individually modeled at 0-9,
below det. limits)
Eberswalde
4
TES dust cover index
-20N, 330E
  • lt0.95 high dust cover
  • gt0.97 low dust cover
  • Refer to Ruff and Christensen 2002 for details
    about the index
  • Values in proposed ellipse are uniform and high
    (0.97), indicating relatively low dust cover
    compared to classic high-albedo regions

Eberswalde
Holden
-30N, 320E
Eberswalde
5
TES 465/530 indices
  • 465 cm-1 feature is present in clays, zeolites,
    amorphous silica, silica glass
  • 530 cm-1 feature is present in olivine pyroxene,
    and some clays
  • High values of both features indicative of
    smectite clays Ruff and Christensen, 2007
  • In Eberswalde, areas where both indices are
    present above the detection threshold are absent
    within the landing ellipse

Eberswalde
6
Summary
  • Olivine basalt THEMIS spectral unit is relatively
    uniform across the region
  • No other spectral units are observed
  • Within the landing ellipse, TES dust cover index
    values are high, indicating relatively low dust
    cover compared to classic high albedo regions

Eberswalde
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