Weathering and

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Weathering and Soil Formation
The speed rocks weather depends on a few factors
check em out
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1. Mineral Composition The harder the minerals
that make up a rocks composition, the slower the
rate of weathering
Limestone Sedimentary Non-resistant
Granite Igneous Resistant
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• Rock Type Some rocks are more resistant to
  weathering based on how they formed
• - Igneous and Metamorphic Rocks have minerals
  strongly bonded together and are resistant
• - Sedimentary Rocks are
• less resistant rocks b/c of
• weak bonds holding them together

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4. Climate a. Cold and Humid Physical
weathering is dominate at high latitudes
altitudes b.
Hot and Humid Chemical weathering is
dominate at low latitudes altitudes.
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• Hot Humid Climates favor
• Chemical weathering
  - oxidation
• 2. Plant Action

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Lichens live off of minerals in the rocks and
produce more soil than anything else on Earth.
Chemical weathering occurs when lichens secret
acid which breaks down rock.
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Physical weathering is dominate at high latitudes
altitudes.
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The process leads to smaller and smaller rock
fragments and over time develops rock into soil
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Products of Weathering Weathering produces
sediments and soils
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2. Soil Types   a. Residual Soils formed from
the local bedrock and have the same mineral
composition.   b. Transported Soil that has
been moved the sediments do not have the same
composition as the local rock
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• Soil Horizons
• Top layer rich in organics (Humus) minerals
• Sediments found here have minerals that were
  dissolved from above, infiltrated when it
  rained
• C. Mostly particles from the local bedrock

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Soil development Soils are the result of
weathering and biological activity over long
periods of time. Stage 1 Mostly un-weathered
bedrock Stage 2 Development of top soil by
biologic activity Stage 3 Thick and well
developed soil horizons (A,B,C)
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• Soils are considered non-renewable resources in
  most areas since only 1 inch is made every 100
  years.
• Different climates will produce different soil
  types at different rates

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THE END