Sedimentary Rocks 3 Flashcards

Terms Definitions
Fine-grainedCommonly massiveFeels gritty on teeth
Medium-grainedOften consists of quartz, feldspar, rock fragments, and/or clay
Agents of Erosion
waterwindgravity ice
Rock Gypsum
Composed of GypsumMassive, crystallineWhite to yellowCan be scratched with fingernail
Physical, chemical, and biological process that transforms sediments into rock.
sedimentary rocks made from particles precipitates from a solution
Sedimentary Rocks
Form by deposition, accumulation, compaction, and cementation of mineral/organic particles, or through precipitation of minerals from water.
Transformation of loose sediments into rock.
Phase of lithification in cement, meinerals from groundwater, that fills the spaces between clasts & attached grains.
Causes of mass wasting
EarthquakesOver-saturation (snowmelt, storms)Grading slopes too steadilyRemoving vegetative cover
Types of Chemical Weathering
Dissolution, Hydrolysis, Oxidation
Pattern of interlocking crystals, may resemble an igneous rock
Mud-sized particles in thin layers that are commonly referred to as laminea, the most common sedimentary rock.
Cementing Agents
1. Silica (SiO2)2. Fe-oxide (Fe2O3)3. Cacite4. Clays5. Tar (organics)
Stratigraphic Formation
Sequence of strata distinctive enough to be traced across a fairly large region.
corners and edges get rounded during erosion via abrasion -longer transport = more rounded -harder minerals are more resistant
chemical Bonds break between atoms and molecules then disperse in water
detrital rocks
type of sedimentary rock made from pieces of other rocks
combo of roundness and sorting -rounder & better sorted typically imply longer transport
What is diagenesis?
involves pressure, heat, and chemical reactions. which lithifies the sediment to make sedimentary rock.
Mechanical or Physical Weathering
Physical process that breaks large rocks into smaller fragments
What are the 2 types of sedimentary rocks
1. Clastic2. Chemical/Biochemical
Why are sedimentary rocks important?
Sedimentary rocks are important for economic reasons because they may contain Coal, Petroleum and natural gas. Metals such as iron, aluminum, and manganese.
What information do sedimentary rocks contain?
Contain evidence of past environments, provides information about sediment transport, often contain fossils
Landslide -rockfall, talus -rockslide -avalanche
mass wasting -solid rock drops straight of slope, rock debris at base -slide, rather than fall (slower) -move lots of material downhill very fast (flows)
Rock Salt
Tiny Skeletal remains
Fine plants remains
rocks and pebbles
Microcrystaline, bubbles if powdered
rounded clast
long transport distances
the act of crushing
transport of rock fragments
Fine grained, reacts with HCL
Coal (carbonized plant fragments)
clastic, cpo
Inorganic or organic; calcareous mudstone; often beige in color
biochemical rocks
chert, conquina, and coal
Sedimentary Structures
surface features formed on
sedimentary layers during deposition or soon thereafter, by arrangement of
grains in beds

Inorganic varieties
true chemical sedrox...from solutions
Sediments are deposited when the source of transportation can no longer carry them
Approximately ____ percent of earth's land surface is covered by sedimentary rocks
gerneration of rock via rock disintegration
Sedimentary rock formed from material (such as shells) produced by living organisms. (limestone, skeletal limestone, micrite)
rock that is high in quartz
What are 2 processes of lithification?
round, solid masses of calcium carbonate often found in layers of shale
rock made of precipitated sea water
like limestone, from evaporation of marine basins
order of rocks?
shale, tufa, sandstone, conglomerate, limestone
clast composition
provides clues about sediment source and depositional environment
a sedimentary rock formed of meterial deposited from solution by evaporation of water
type of limestone made of shell fragments
All _________ are deposited on the surface of the Earth.
chemical rock
rock salt or halite
rock gypsum
some limestone-uncommon
sedimentary breccia
a sedimentary rock consisting of sharp angular fragments embedded in clay or sand
-formed in ocean basins; vary by depth

From continental shelf, continental slope to abyssal depths
The 2 major evaporite minerals are
gympsum and halite
oil trap
a geological structure that allows for significant amounts of oil and gas to accumulate
Continental environment
Glacial (moves sediment of any size, collects all sediment in its path), mountain stream (fast moving water, carry large clasts, they settle to form gravel and boulder beds, finer sediments get carried downstream), alluvial fan environments (stream empties sediment near mountain front producing a wedge-shaped apron of gravel and sand), Sand dune environments, river environments.
Types of Lithification- Compaction
Weight of overburden compacts sediment
Ex= Leaning tower of pisa
Sedimentary rock
forms when sediments are compacted and cemented together or when minerals come out of solution or are left behind by evaporation
sediment transport agents
include waves, lake currents, river currents, wind, ice, meltwater, ocean currents, turbidity currents, tidal currents, tides.
anthracite coal
hard natural coal that burns slowly and gives intense heat
sedimentary breccia
a sedimentary rock consisting of sharp angular fragments embedded in clay or sand
origin of sedimentary rocks
deposited at earth's surface, temp cool, pressure low, transported by wind, water, ice, typically deposited as LAYERS or STRATA
Origins of Sedimentary Rocks
1) Detrital= "WORN" accumulations of eroded rocks
Example: Sandstone
2) Chemical= Chemicals precipitates
Example: Rock Salt
Stable minerals
last a long time at earth's surface. Quartz and hematite
sedimentary structures: mud cracks
polygonal cracks formed in drying mud
alternating wet and dry
always 3 directions
What ar ethe most common minerals found in mature sedimentary rocks
Quartz or calcite
Compaction and cementation
What are the two major processes of lithification?
How sedimentary rocks formed can be determined by
texture & mineral composition
-ocean basins
-in submarine fans from submarine canyons
Turbidites on steep slopes in...
What does the term "mature" mean when describing sed rocks?
well-sorted, well-rounded quartz grains and has been transported @ great distance
How does physical weathering speed chemical weathering?
- increase in surface area accelerates chemical rxns
- chemical weakening increases surface area via breakage
/ 76

Leave a Comment ({[ getComments().length ]})

Comments ({[ getComments().length ]})


{[ comment.comment ]}

View All {[ getComments().length ]} Comments
Ask a homework question - tutors are online