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30 terms

Mrs. Storiz Sedimentary Rocks

Sedimentary Rock samples
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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.