Mechanical

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Mechanical weathering -- tree roots
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Mechanically weathered clasts on a mountain side
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exfoliation
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Heat-cold weathered clast in the desert
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Controls on chemical weathering
SLOW FAST
Rock type (name of the rock) granite Basalt (higher T minerals)
Rainfall Low rainfall High rainfall (H2O, O2, combination with CO2)
Temperature Cooler temps Higher temps (heat speeds up reactions)
Vegetation Sparse vegetation lower rate (nothing to promote chem rxns) Lots of vegetation plants create oxygen, tannins, acids
Soil cover More soil cover/rocks exposed at surface OR More soil cover Soil decomposes, gives off heat, holds rain water, chm rxn
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A few questions about seawater

• What are the main ions in seawater (what makes it
  salty)?
• Where do these ions come from (where do most ions
  in seawater come from)?
• Why is seawater so salty?

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Poorly sorted conglomerate
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Coarse-grained sandstone
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Very fine-grained sandstone/siltstone
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chert
travertine
limestone
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Angular clasts in a very fine matrix (poorly
sorted, close to source)
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Round clasts, well sorted, diverse types, far
from source
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Beds (lake beds actually)
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The texts word on how to create graded bedding
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