Geomorphology of Eastern Meridiani Planum

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Geomorphology of Eastern Meridiani Planum
Kevin Lewis California Institute of Technology
Image Credit Cornell/JPL/NASA
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Regional Geology of Meridiani
Region of Interest
Etched Terrain
Hematite Unit
(Hynek, et al., 2002)
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Region of Interest
Layered Blanket
Dozens of layers
Linear features
1 km
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Data
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Data Moc vs. MOLA

• Overall, Stereo and MOLA DEMs show similar
  profiles.
• Baseline for Stereo has NOT been adjusted to MOLA
  
• 100x vertical exaggeration

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Notable observations

• This depression has an anomalously low
  depth/diameter ratio (1/60)
• The basin seems to tilt to the North
• Several layers inside form distinct benches
• The inferred stratigraphy implies regional
  folding
• A fresh impact crater, which punches through the
  etched layers, aids in reconstructing the
  stratigraphy

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Geologic Model
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Formation Mechanisms
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1 Impact Crater with Fluidized Ejecta

• Evidence for
• Looks like a crater
• Craters are common!
• Explains blanket around circular feature
• Evidence Against
• Layers appear undisturbed
• Fails to explain uniqueness of feature
• Ejecta blankets do not normally have as many
  layers

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2 Circular Anticline

• Evidence for
• Complex layering
• Shallow depth
• Evidence of folding
• Evidence Against
• Requires a very localized uplift
• Does not explain lithification
• Model requires 2x thickness of layered unit

www.lpi.usra.edu/images/ sgeo/sgeo_S13.gif
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3 Hydrologic Feature

• Evidence for
• Provides an explanation for complex erosion
  patterns
• Could create layering and lithification
• Evidence of water at Opportunity site
• Evidence Against
• No other clear signs of hydrologic activity in
  this unit
• Likely too large to be a hydrothermal basin
  (geyser) see Hynek et al, 2002

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Conclusions and Unresolved Questions

• An anticline or a hydrologic origin are most
  likely from this research however, all the
  scenarios tested have problems, which do not fit
  the data
• Are there possible formation mechanisms which
  have not been addressed?
• How does this area tie into the regional geology?
• What is the mineralogical composition of this
  unit?

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Another possibility...?
Image Credit easyweb.easynet.co.uk/aburnham/
eng/arborhi2.htm