Sedimentary rocks contain evidence of the crystallization sequence of minerals produced by solidifying magma.
if sedimentary rocks account for only about 5% of the earths top 10km, which of the following is NOT a reason why sedimentary rocks are still considered “important”
weathering, erosion, deposition, lithification
Which of the following lists the correct sequence in the formation of a sedimentary rock?
Burial subjects the sediment to increasingly higher temperatures and pressures.
How does burial of sediment promote diagenesis as sediment converts to rock?
evaporite
Which type of sedimentary rock is NOT formed by either compaction or cementation?
detrital and chemical
What are terms for the two principal sources of sediment that produce the two principal types of sedimentary rocks?
quartz – it is extremely durable and resistant to chemical weathering
clay – it is the most abundant product of chemical weathering of feldspar
clay – it is the most abundant product of chemical weathering of feldspar
What minerals are most common in detrital sedimentary rocks and why?
particle size – a useful observation indicating the environment of deposition
What is the primary basis for distinguishing among various detrital sedimentary rocks? Why?
calcite – it is soft and relatively soluble in water
Detrital grains of some mineral(s) are extremely rare in detrital sediments. Which minerals and why?
Shale crumbles easily, causing increased mechanical weathering, whereas sandstone resists weathering more effectively.
If shale is such a common rock in the sedimentary rock world, why isn’t it as prominently exposed at the surface as sandstone?
shale, sandstone, conglomerate
Select the answer that lists the common detrital sedimentary rocks in order of increasing particle size.
Layers of sand-size quartz-rich sediment found today at the beach are virtually identical to layers in a 10 million-year-old sandstone, thus suggesting the location of the sandstone was the location of a beach 10 million years ago.
Which of the following is a feasible explanation as to why quartz sandstone is an excellent use of “uniformitarianism” (presented in Chapter 1)?
false
Calcite, feldspar, and iron oxide are the most common cements.
Evaporite minerals are more soluble than calcite and quartz.
Which of the following is true for minerals in chemical sedimentary rocks that form by evaporation?
evaporites
The minerals gypsum and halite are found deposited in lake environments. Which kind of chemical sedimentary rock do they form?
mineral solubility – less soluble minerals precipitate first, more soluble minerals precipitate later
When a body of seawater evaporates, minerals precipitate in a certain order. What determines this order?
Coal is representative of a former swamp environment, whereas limestone represents marine environments
Coal is formed from the fossilized remains of plant material, whereas limestone is formed with calcium carbonate.
Coal is formed from the fossilized remains of plant material, whereas limestone is formed with calcium carbonate.
How is coal different from other biochemical sedimentary rocks? Choose all that apply.
clastic; nonclastic
The two major textures used in the classification of sedimentary rocks are __________ and __________.
The rounder and better sorted grains indicate farther travel from the source.
The more angular and poorly sorted grains indicate shorter travel from the source and higher energy of the environment of deposition.
The more angular and poorly sorted grains indicate shorter travel from the source and higher energy of the environment of deposition.
How are the degree of sorting and the amount of rounding of grains related to the transportation of sand grains? Choose all that apply.
Breccia clasts are angular, whereas conglomerate clasts are rounded.
What is the difference between conglomerate and breccia?
Fine grain sizes imply longer travel from source areas and slow-moving water
How is grain size in sedimentary rocks related to the energy of the environments of transport and deposition?
Texture of a rock can be used to indicate the composition and source of the sedimentary particles in it.
As with all rocks, texture of sedimentary rocks is an extremely important tool used by geologists. Which one of the following is NOT a reason why?
continental, marine, transitional
Which of the following lists includes the three most common sedimentary environments?
age of the rock
Which one of the following can NOT be determined from an understanding of the conditions under which sedimentary rocks form?
striations
Which one of the following is NOT a type of sedimentary structure?
bedding / stratification – each bed / stratum difference represents variation in the original depositional environment
Which is considered the most important original depositional feature of sedimentary rocks and why?
false
The thickness of a sedimentary bed is directly related to the time it took to deposit the sediment.
ripple marks and cross-bedding
Which type of sedimentary structure can be used to determine current direction?
True
The deposition of a graded bed is most often associated with a turbidity current, a mass of sediment-choked water that is denser than clear water and that moves downslope along the bottom of a lake or ocean.
shale, sandstone, conglomerate
Which of the following lists ranks the indicated sedimentary rocks from low-energy to high-energy environments of deposition?
Current ripples indicate current direction, oscillation ripples indicate wave action.
Current ripples are asymmetrical, oscillation ripples are symmetrical.
Current ripples are asymmetrical, oscillation ripples are symmetrical.
How do current ripple marks differ from oscillation ripple marks? Choose all that apply.
apatite and sylvite – these are a phosphate and a potassium-bearing mineral, respectively
Which of the following is a good fertilizer, and why?
gypsum
Which of the following is an essential component of plaster and wallboard for construction?
remains of organic material (carbon)
Fossil fuels are those that form from the ___________.
their energy content was derived from “ancient” sunlight, trapped in the material
Why are “coal” and “petroleum” products considered to be “fossil fuels”?
to generate electricity
Which of the following accounts for the majority of the coal burned annually in the United States?
