week 2

Question 1

weathering

Answer 1

• the breakdown of rocks and minerals
• occurs because rocks formed inside Earth at high temp and pressure are unstable at surface temps/pressures

Question 2

4 types of physical weathering

Answer 2

1. temperature / exfoliation: exterior of rock heats up more in the sun than interior, causing stress so outer layers flake off
2. ice
3. wind (carrying abrading particles)
4. roots / organisms

Question 3

4 types of chemical weathering

Answer 3

1. dissolution: dissolving in water
   
   • ex: calcite… CaCO₃ -> Ca⁺² + CO₃^-2
2. ^​hydrolysis: addition of water adds H+, replacing some other cation (like K+)
3. acidolysis: like hydrolysis but w/ an H+ donating acid
   
   • esp. organic acids & carbonic acids
4. oxidation/reduction rxns

Question 4

parent material influences… (7)

Answer 4

1. soil texture
2. water movement
3. pH
4. weathering rates
5. nutrient cycling
6. depth of soil
7. horizons

Question 5

Consolidated Parent Material

Answer 5

Consolidated: rocks / continuous bedrock

• Igneous: from consolidation of magma
  
  • Intrusive: cools slowly below earth’s surface, so larger crystals; ex: granite, diorite
  • Extrusive: released to surface while molten, so cools rapidly, so smaller crystals; ex: lava, basalt, andesite
• Sedimentary: consolidated sediment and/or loose rock
  
  • compaction/cementation; ex: sandstones, siltstones
  • Precipitation from solution (lake, sea); ex: salts, carbonates, limestone
• Metamorphic: rocks from partial remelthing of rocks, recooled into new rocks; ex: schist, gneiss, marble

Question 6

Unconsolidated Parent Material

Answer 6

unconsolidated: any fragmented materials

• residual: unconsol. bedrock, broken up in place
• transported: classified by how it was moved
  
  • gravity
    
    • colluvial: talus; rock slides
  • water
    
    • alluvial/fluvial: stream or river deposits
    • marine: erosion of soil, deposition along shoreline
    • lacustrine: lake deposits, fine-textured, layered from annual deposits
  • wind
    
    • eaolian/eolian deposits (loess); ash
  • ice (glacial deposits)
    
    • moraines: loose rock deposited at side of front of glacier; typically forms hill of loose, unsorted rock
    • outwash: melting ice -> river -> coarse and fine layers of rounded rock
    • glacial lacustrine: glacial lake sediments
    • till: unsorted rock carried by ice
      
      • basal till: carried at bottom of glacier; mixed rock and fines that move slowly w/ ice; unsorted, very compacted
      • ablation till: carried w/in ice, deposited as glacier melts; unsorted, but not compacted

Question 7

drumlins

Answer 7

cigar-shaped hills formed by glacial deposits that are parallel to flow of glaciers