Sedimentary Rocks

Clastic / Physical / Detrital

Chemical

Bioclastic/Biochemical

Fig. 06.38

tillss, cong

sh

ss, sh

ss, cong

ss, slt, sh

ss

ss

ls

sh

ss, slt, shgraywacke

chert, chalk, sh

Sedimentary Rocks

Clastic/Physical/Detrital Sedimentary Rocksclassified by texture (grain size, roundness)

Conglomerate (with rounded gravel)

Breccia (with angular gravel)

Sandstone (sand)

Siltstone (silt)

Claystone or Mudstone (clay)

Shale – fissile (clay)

Sedimentary Rocks

Chemical Sedimentary Rocksclassified by composition

Limestone (many varieties) – Calcite, Dolomite

oolitic LS, crystalline LS, travertine, dolostone

Chert – Silica

Evaporites – Halite, Gypsum, Sylvite, Anhydrite

Rock Salt, Rock Gypsum

Sedimentary Rocks

Biochemical/Bioclastic Sedimentary Rocks Limestone (many varieties) – Calcite, Dolomite

coquina, fossiliferous LS, chalk, micrite

Chert – diatoms, silica

Coal

peat, lignite, bituminous coal

anthracite – actually metamorphic

http://www.glossary.oilfield.slb.com/

Wentworth ScaleBoulders Cobbles Gravel (pebbles)SandSiltClay

Sedimentary clasts are classified by grain size (the size of the individual clasts) using the Wentworth Scale:

Larger clasts require more energy to

transport

Smaller clasts require less energy to

transport

http://csmres.jmu.edu/geollab/Fichter/SedRx/chembiokey.html

Evaporites minerals precipitated from evaporating water

Siliceous Rocks Silica and opalline silica precipitate either organically or inorganically

Coal and Peat Carbon-rich deposits formed from build-up of plant material in swamps

CarbonatesVariety of limestones composed of calcite, aragonite, and dolomite precipitated either organically or inorganically