Rock Cycle

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 RocksConglomerate; large, coarse rounded grains

Detrital Sedimentary RocksBreccia; large, coarse angular grains

Detrital Sedimentary RocksSandstone; primarily composed of medium sized

quartz grains (feels sandy)

Detrital Sedimentary RocksSiltstone; composed of fine grained quartz and

clay

Detrital Sedimentary RocksShale; composed of very fine grains of the mineral

clay and quartz

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 RocksBituminous Coal; composed of altered plant

remains (will burn)

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

Chemical Compounds of Sedimentary Rocks

• Calcite CaCO3

• Dolomite CaMg(CO3)2

• Quartz SiO2

• Gypsum CaSO4*2H2O• Halite NaClIndicator - • Hydrochloric Acid HCl