The Search for a Topographic Signature of Life

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The Search for a Topographic Signature of Life

• William Dietrich and Taylor Parron

Presenters Claire Steiner and Marina Drazba
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The Equation
Breaking it down
Change of elevation with time Uplift Incision
to bedrock Stored sediment
What it means
Change of elevation with time Tectonics
Erosion loose soils
Dependent on
Change of elevation with time Geology Geology
and climate geology, topography and water
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The Erosion
Erosion of soil
Erosion of bedrock
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Abiotic Vs Biotic Earth

• Short Time Scale Impacts
• Geologic Time Scale Impacts

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Short time scale impacts

• Curvature of bedrock
• Riverbed composition
• River shape

• Overall
• Rapid Erosion

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Hypothesis 1 Curvature of bedrock

• Abiotic World

- Stripped Landscapes - Rough bedrock exposed
Biotic World - Smooth, rounded, soil covered
hilltops
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Curvature of bedrock
Exposed Bedrock
Atacama Desert Chile
Rounded Hillslope
Atacama Desert Chile
Rounded Hillslope
Mars
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Hypothesis 2Riverbed composition

• Abiotic World
• Coarser Riverbeds
• Steeper Riverbeds

• Biotic World
• - Less Coarse Riverbeds
• - Shallower Riverbeds

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Riverbed composition
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Hypothesis 3 River Shape

• Abiotic World
• No Meandering Rivers
• Braiding

• Biotic World
• Meandering
• Braiding

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River Shape
Yamal tundra
Ólafur Ingólfsson, 1997
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Geologic time scale impacts

• Climate
• Precipitation

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Precipitation Model Kleidon et al.

• Abiotic World
• Higher Albedo
• Low Storage of Water
• 0 Vegetation Cover

• Biotic World
• Lower Albedo
• Optimized Water Storage
• 100 Vegetation Cover

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Precipitation
June - August
Increase in Precipitation
Decrease in Precipitation
No change in Precipitation
Difference in Precipitation (mm/day)
Kleidon et al., 2000
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Precipitation
Willett, 1999
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Precipitation
Willett, 1999
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Frequency and distribution of landform properties
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Frequency and distribution of landform properties