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