-
Sedimentary rocks make up less than ___ percent of the crust.
10
-
Sedimentary rocks cover ___ percent of the continents.
70
-
Where are sedimentary rocks made?
On the surface of the earth
-
How is a sedimentary rock formed?
Sediment buried & squeezed
-
Define weathering.
Breaking apart rock, mechanically and chemically.
-
Define erosion
The moving rock parts somewhere else
-
List mechanical erosion methods
Water, wind, gravity (landslides), ice
-
Define clast.
A chunk of rock; clay, sand, gravel
-
Define chemical erosion.
occurs when water transports dissolved minerals away from their source rocks (example: acidic rainwater dissolves limestone & it ends up in caves)
-
Define mechanical deposition
Slide stops, wind/water slows, ice melts
-
What is compaction?
Sediment compacted into a denser state,reduction in void space btn particles
-
Define cementation:
Chemical precipitation in pores; filling of void spaces by chemical precipitation
-
What is porosity?
Measure of relative amount of void space
-
Besides compaction and cementation, what can also contribute to the lithification of rock?
Crystallization; crystal growth w/in the void spaces in a rock
-
Define clastic sedimentary rock.
Sediments --> rock
-
What are the types of sediments ordered from small to large?
Clay, sand, gravel
-
What is the most common mineral in sand?
Quartz
-
What depositional environments will you get poorly sorted clastic sediments?
landslade, glacier, slow streams
-
What depositional environments will you get well sorted clastic sediment?
Slow streams & wind, beach (waves)
-
What sediment makes conglomerate?
rounded gravel particles, sediments of high-velocity streams
-
Describe breccia.
Like conglomerate except w/ angular particles
-
Describe sandstone.
- Made of sand, quartz
- 10% of sedimentary rocks
- strong, hard to eroid
- cemented together
-
Describe shale.
- Made of clay
- 2/3 of all sedimentary rocks are shale
- splits into thin slabs (fissile)
- weak, easy to erode
-
What is oomicrite?
rock containing abundant oolites w/in a muddy matrix
-
How is a chemical sedimentary rock created?
Chemical transport of rock particles - dissolved in water, deposit chemically
-
How is limestone formed?
Biochemical, from shells on seafloor (calcite), dissolved over 100s-10,000 of years
-
Describe limestone
- strong, easy to erode because it is water soluble
- changes through time rapidly on a geological scale
-
What percentage of sedimentary rocks is limestone?
15
-
What are other important chemical sedimentary rocks?
Chert, quartz
-
How is iron ore formed?
Water with dissolved iron but cannot be oxidated
-
Name two evaporites.
gypsum, salts
-
Describe the strength of an evaporite.
Extremely weak, behaves as plastic material under pressure.
-
What is bedding?
Sediment laid down in layers/beds/strata
-
What is stratigraphy?
Study of layers and what has happened at a particular time; the branch of geology that deals w/ the horizontal and vertical changes and relationships between sedimentary rock units
-
What is uniformitarianism?
The processes used to understand rocks and rocks used to understand processes
-
What is a fossil?
Remains of life (footprints, burrows, feces, etc.)
-
What are facies?
Depositional environments that are divided into subenvironments
-
What sedimentary rocks are most likely to form on a steep slope?
Clastic, bad sorting, many types of rock, conglomerate
-
What sedimentary rocks are most likely to form on a glacier?
Clastic, bad sorting, contains large particles, conglomerate
-
What sedimentary rocks are most likely to be formed at a desert by wind?
clastic, well-sorted, sand --> sandstone
-
What sedimentary rocks are most likely to be formed at a desert by evaporatoin?
Chemical-evaporation of water, salt, phosphates, & gypsum
-
What sedimentary rocks are most likely to be formed by wind-blow dusty soils?
caused by drought and bad agricultural practices, clastic, very good sorting, shale
-
What sedimentary rocks are most likely to be formed in a fast-moving river?
bad sort, boulders & gravel.
-
What sedimentary rocks are most likely to be formed in a slow-moving river?
Clay & sand, good sorting
-
What sedimentary rocks are most likely to be formed at the mouth of a river?
sand & clay, really good sorting
-
What is a delta?
When the river hits the sea
-
What sedimentary rocks are most likely to be formed at a lake?
really fine-grained sediments deposited on lake bed, good sorting
-
What sedimentary rocks are most likely to be formed in a swamp?
sediment made out of plants --> coal (dead stuff that never gets biodegraded)
-
What sedimentary rocks are most likely to be formed on a coast?
Waves --> very well sorted; sand & pebbles from river mouths or weather/erosion
-
What sedimentary rocks are most likely to be formed at a coral reef?
limestone
-
What sedimentary rocks are most likely to be formed in the deep ocean?
mix of stuff to make chert, oil, and limestone
-
What are Appalachian Valley & Ridge ridges made of?
shale, sandstone, limestone; ridge top: sandstone
-
What are Appalachian Valley & Ridge valleys made of?
shales and limestone
-
What sedimentary rocks are mined for construction?
gravel, sand, brick, cement, limestone, sandstone
-
What chemicals serve as resources?
lime, salts, fertilizer, gypsum (plaster), iron ore
-
lime is an important ___.
antacid
-
What percent of energy comes from fossil fuels?
85
-
Most groundwater usage is from ___.
Sediment & sedimentary rock
-
What is the porosity and permeability of shale?
low porosity, low permeability.
-
What is the porosity and permeability of sandstone?
high porosity, high permeability
-
What is the porosity and permeability of limestone?
irregular porosity, highly irregular limestone; water flows fast through caves and cracks.
-
-
Is clay permeable?
Not very.
-
-
-
What does detrital origin mean?
when fragments have been eroded, transported, and deposited.
-
What does nonclastic mean?
grains form an interlocking network similar to igneous rocks w/ crystalline texture.
-
What is parallel bedding produced by?
Transport of sediment by currents or by deposition in standing bodies of water where sediment particles fall through a column of water to their resting points on the bottom.
-
What is cross bedding?
Result of deposition of sediment that moved in wavelike bedforms near sediment-fluid interface
|
|
