LIMESTONES• Calcite (calcium carbonate) dominates• Fine-grained
– Chalk (cliffs of Dover, England)
• Medium-grained– Oolitic limestones
• Coarse-grained– Coquina (broken shells loosely cemented)
– Fossiliferous limestones
CHERT• Microcrystalline silica (microquartz = silicon dioxide)• Many varieties:
– Flint = gray due to organic matter– Jasper = reddish due to iron oxides– agate = banded structures
• Scots Bay Formation at Ross Creek
EVAPORITES• Precipitated crystals from
– oceans– lakes– rivers
• Halite (sodium chloride)
• Gypsum (hydrated calcium sulfate)
Death Valley, California
COAL
• Compressed, heated thick accumulations of organic matter
• With little detrital sediment to form much ash
• Environment: vegetation in a lush swamp
• Well-known from Carboniferous Period of Nova Scotia
Coalfields of Nova Scotia
FOSSIL FUELS
• Alteration of partly decayed and buried organic matter.
• Coal solid rock
• Petroleum liquid in pore
• Natural gas gas (mostly methane) spaces
• Coal is mostly from terrestrial plant matter, but petroleum and natural gas come mostly from marine animals, plants and micro-organisms
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