Mrs. Storiz Sedimentary Rocks

Terms	Definitions
sediments	materials that settle out of water or air. Some can contain pieces of plant or animal remains.
coal	an unusual sedimentary rock that forms from plants instead of earlier rocks. Formed millions of years ago in swamps.
clastic sediments	make up >75% of all sediments on the earth's surface.
chemical precipitates	Minerals that are precipitated from concentrated solutions.
Biogenic sedimentary rocks	Sediments that are produced through the life activities of plants and animals. (sometimes called biochemical)
boulder	> 256 mm
cobble	256 - 64 mm
pebble	64 - 4 mm
granule	4 - 2 mm
sand	2 - 1/16 mm
silt	1/16 - 1/256 mm
clay	< 1/256 mm
conglomerate	Sediment Type: clastic Grain Size: gravel Common Sedimentary Environments: river channels, glacial till, alluvial fans
Breccia	Sediment type: clastic Grain Size: gravel Common Sedimentary Environments: near-surface faults or near sediment source areas Angular clasts
sandstone	Sediment type: clastic Grain Size: sand Common Sedimentary Environments: beach, desert
mudstone	Sediment type: clastic Grain Size: silt and clay (mud) Common Sedimentary Environments: low energy environments such as lakes, deep ocean, flood plains, and deltas
shale	Sediment type: clastic Grain Size: silt and clay (mud) Common Sedimentary Environments: low energy environments such as lakes, deep ocean, flood plains, and deltas.
chert	Sediment type: chemical/biogenic Composition: quartz Grain Size: microscopic Common Sedimentary Environments: groundwater precipitate or deep-marine biogenic accumulations
Rock Salt	Sediment type: chemical Composition: halite Grain Size: mostly fine grained Common Sedimentary Environments: desert lakes and marine areas with high evaporation rates
Rock Gypsum	Sediment type: chemical Composition: gypsum Grain Size: variable, commonly fibrous or granular and medium to fine grained Common Sedimentary Environments: desert lakes and marine areas with high evaporation rates (often forms in same environment as rock salt)
Travertine	Chemical sedimentary rock. Generally banded. Usually very fine grained. Formed in caves. Composition: calcite.
Limestone, chalk	Formed by the accumulation of microscopic marine calcite fossils. Biochemical sedimentary rock. Very fine grained. Composition: calcite. Environments: marine
Fossiliferous limestone	Biochemical. Formed by the accumulation and consolidation of macroscopic calcite fossils. Composition: Calcite. Medium to coarse-grained. Environments: warm, shallow, marine areas.
Oolitic limestone
dolostone
diatomite	Biochemical sedimentary rock. Composed of mainly skeletons of common marine plankton- diatoms. The skeletons are composed of silica-dioxide.
bituminous coal	Formed by the accumulation of plant material. Composition: carbon rich. Very fine grain. Found in swamps.
anthracite coal	Sometimes called "hard coal". Forms from bituminous coal when great pressures developed in folded rock strata during the creation of mountain ranges. Has the highest energy content of all coals.
lignite	Lowest rank of coal. Increased pressures and heat from overlying strata causes buried peat to dry and harden into this. Is a brownish-black coal with generally high moisture and ash content and lower heating value.
coal - peat	A mass of recently accumulated to partially carbonized plant debris. This material is on its way to becoming coal but its plant debris source is still easily recognizable.