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Sedimentary Rocks
• Fossil source rock• Made from weathered and eroded igneous
and metamorphic rocks• Indicate past climates/environments• Petroleum, natural gas, iron, aluminum, and
sulfur occur in the pores
•Weathering – the disintegration and decomposition of rock at the surface of the Earth•Erosion – the incorporation and transportation of material by a mobile agent, such as water, wind or ice•Sediment – unconsolidated particles created by the weathering and erosion of rock•Precipitate – process that separates solids from a solution; forms evaporites•Lithification – process of converting sediments to solid rock by cementation and/or compaction
Detrital Sedimentary Rocks
• Detrital sedimentary rocks can be made of detrital material that consists of mineral grains or rock fragments from the process of mechanical weathering that are transported and deposited as solid particles
Detrital Sedimentary RocksArkose; composed of reconsolidated particles of
minerals such as feldspar and quartz
Sedimentary Rocks
• Chemical sedimentary rocks are composed of chemical material that was previously dissolved in water and later precipitated by either inorganic or organic processes
• Chemical sedimentary rocks formed from the process of water-dwelling organisms are biochemical sedimentary rocks
Chemical Sedimentary RocksCoquina; biochemical sedimentary rock
containing visible shells, loosely cemented together
Chemical Sedimentary RocksLimestone; biochemical sedimentary rock
containing fine shells composed of the mineral calcite that have been cemented together with fine, crystalline calcite (will effervesce with HCl)
Chemical Sedimentary RocksChalk; composed of microscopic shells and clay
(diatomaceous earth)
Chemical Sedimentary RocksTufa; light, porous limestone that forms in springs
and caves (stalactites & stalagmites)(will effervesce with HCl)
Chemical Sedimentary RocksRock Salt (halite); formed as water evaporates
leaving formerly dissolved material to precipitate
Chemical Sedimentary RocksDolostone; fine to coarse crystalline calcite (will
effervesce with HCl) Sample has dolostone crystals called Celestite
Chemical Sedimentary RocksChert; very fine crystalline quartz (used to make arrow
heads and other weapon and tool tips because of conchoidal fractures
Chemical Sedimentary RocksGypsum; composed of fine to coarse crystalline
calcium sulfate Sample has gypsum crystals called Selenite
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