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CH3041
SEDIMENTARY ROCKS
• 80% of the basement is covered with sedimentary rocks (average depth of 5km).
• The chemistry of the Earth’s surface is largely concerned with the chemistry of the sedimentary rocks:
 Mudrocks    (60%) - clay minerals, quartz
 Carbonates (20%) - limestones, dolomites
 Sandstones (15%) - quartz
Quartz             - Silicate mineral SiO2
Clay minerals - Sheet Silicates
                          eg. Al4Si4O10(OH)8 kaolinite
Limestones CaCO3  Dolomites CaMg(CO3)2