Principle of _____ __________ Most sedimentary layers of rock are deposited in a horizontal position, with older rocks laid down first
_________ Sediment becomes sedimentary rock through ________, which involves: _________ Recrystallization (of carbonate sediment) Ex: sand Remember that SiO 2 is released into groundwater from the chemical weathering of quartz and feldspars.
3 Classes of Sedimentary Rock _______ - fragments of rock debris produced by physical weathering. Ex. Sand & clay. _______- sediment precipitates from solution in water. Ex. Calcium carbonate & salt. _______ - sediment composed of the fossilized remains. Ex. Coal, oil, & natural gas.
Gravel Clastic Rocks If rounded clasts = ____________ If angular clasts = __________
Sand Clastic Rocks Different Sandstones based on dominate grains quartz grains = ________ ____________ feldspar grains = _______ sand-sized rock fragment grains = __________
Clay Clastic Rocks Grains less than 1/256 mm (smooth) _____ (if fissile – splits) ________ (if massive) also called Claystone
Chemical ________ From the evaporation of water (usually seawater). Rock salt - composed of halite (NaCl). Rock gypsum - composed of gypsum (CaSO4.2H20) Travertine - composed of calcium carbonate (CaCO3), and therefore, also technically a carbonate rock
Chemical __________ Formed through both chemical & biochemical processes. Include the limestones (many types) Two minerals are dominant: –Calcite (CaCO3) –Dolomite (CaMg(CO3)2)
Chemical ___________ Dominated by silica (SiO2). From diatoms, radiolarians, or sponges. Diatomite - looks like chalk, but doesn’t fizz in acid. Made of diatoms. Also referred to as Diatomaceous Earth. Chert - Massive and hard, microcrystalline quartz. May be dark or light in color. Often replaces limestone. Does not fizz in acid.
Biogenic (______) Sedimentary Rocks Coals organic matter (plants). Increasing depth of burial (temperature and pressure): –Peat (porous, brownish plant fragments) –Lignite (crumbly and black) –Bituminous (dull to shiny and black; sooty; layers may be visible) –Anthracite (extremely shiny and black; low density; not sooty
___________ from Sediments Large enough to be recognized. Ex.- haystack rock, sand dunes, delicate arch, balanced rock