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10
CH3041
MINERAL DEPOSITION
• Evaporites: evaporation of seawater ppts the evaporite minerals. CaSO4.2H2O(gypsum), NaCl (halite), bittern salts (Mg) - in sequence.
No modern large basin deposits.
No modern large basin deposits.
• Carbonates: the biotic removal of Ca2+ &
HCO3- is the most important mechanism for
the formation of carbonate sediments.
Ca2+ + 2HCO3- D CaCO3(s) + CO2 + H2O
HCO3- is the most important mechanism for
the formation of carbonate sediments.
Ca2+ + 2HCO3- D CaCO3(s) + CO2 + H2O
eg1. Recent (104y)
deposition of skeletons in continental shelves - the Great Barrier Reef.
eg2.
Past (108 y) 0.5 km deep-sea pelagic oozes cover ½ the floor, plankton skeletons.
