eosc 210 - sedimentary rocks

shale

• clastic

• very fine grained

• well-sorted

• rounded grains

• environment: river, lake, swamp; less likely in

  tidal flat or lagoon

lithic sandstone

• clastic

• >15% fine grained matrix like clay

• composed of mostly rock fragments

• fine-grained

• well sorted

• angular, low sphericity

• environment: river (high energy settings)

arkosic sandstone

• clastic

• coarse-grained

• poorly-sorted

• poorly rounded, low sphericity

• commonly reddish in colour (b/c of feldspar)

• environment: river (High energy settings)

red sandstone

• clastic

• coarse-grained

• well-sorted

• rounded, high sphericity

• environment: desert (red), beach, river

• dominantly quartz

• red due to iron oxides

conglomerate

• clastic

• coarse-grained

• poorly sorted

• rounded, high sphericity

• grains of varying composition

• environment: river (medium to high energy setting)

breccia

• clastic

• coarse-grained

• poorly sorted

• angular, low sphericity

• grains of varying composition

• environment: river (high energy setting)

chert

• non-clastic

• conchoidal fracture

• very fine-grained, undistinguishable grains

• contains mainly quartz

• environment: deep marine

microcrystalline limestone

• non-clastic

• reacts strongly with acid

• composed of calcite

• medium to coarse-grained

• may contain fossils

• environment: shallow marine

evaporite

• non-clastic

• composed of halite/table salt or gypsum

• medium to coarse-grained

• environment: tide pools, lagoon

coal

• composed of organic material

• environment: swamp