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79 terms

GEOLOGY TEST 4

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_____ a common mineral found in igneous rocks, is the most abundant mineral in detrital sedimentary rocks
quartz
which major component of detrital sedimentary rocks only rarely occurs as a primary mineral in igneous rocks
clays
zicon and tourmaline are dense, highly insoluble, chemically stable, minor minerals of igneous and metamorphic rocks. In which sedimentary rock might you expect to find these minerals concentrated?
sandstone lithified from quartz-rich beach sand
Sandstone's sediment
sand
Shale's sediment
all clay sediment
Conglomerate's sediment
gravel
Mudstone's sediment
clay and fine silt
compaction is a veyr important part of the lithification process for which of the following sediments
mud
A cherty limestone would contain which major constituents?
silica; calcite
Which of the following best describes bedded gypsum and halite?
evaporates
_____ sandstone contains abundant feldspar, suggesting that the sand was derived by weathering and erosion of granitic bedrock
arkosic
_____ cement produces bright-red and yellow colors in some sandstone
iron oxide
what is probably the single most important, original, depositional feature in sedimentary rocks?
bedding or stratification
Which of the following would retain the most detailed impressions of fossilized organisms?
very fine-grained volcanic ash
What is a bittern?
residual brine left
________ are further concentrated in a residual brine after NaCL is crystalized
potassium, magnesium, and bromine
studies of deep-sea sediment cores have contributed greatly to scientific knowledge of _______
climatic changes
What is the main difference between a conglomerate and a sedimentary breccia?
breccia clasts are angular, conglomerates clasts are rounded
Which of the following describes the correct order for relative solubility of minerals in sedimentary rocks?
evaporate minerals are more soluble than calcite and quartz
A graywacke is _______
a sandstone with sand grains embedded
which statement concerning sedimentary rocks is not true?
they were originally deposited at depth below the bottom of the sea
Which type of limestone consists mainly of tiny, marine fossils composed of calcite?
chalk
____ is not a common cementing agent for sandstones
fluorite
Detrital sedimentary rocks are classified (named) based on the _____
grain sizes of the detritral particles
Which of the following applies to the basic constituents of halite, gypsum, and sylvite?
transported as dissolved ions, deposited by evaporation
Flint, chert, and jasper are microcrystalline forms of
quartz
Sedimentary rocks account for about what percentage of the Earth's outermost 10 kilometers of rock? What percentage of the Earth's continental area is covered by sedimentary rocks?
5% and 75%
Which of the following sedimentary rocks would you expect to have originally been deposited by fast-moving streams?
conglomerate
Which type of sediment undergoes the most compaction as it lithifies to sedimentary rocks?
marine mud
Which of the following Detrital grains of which mineral(s) are extremely rare in detrital sediments? Why?
calcite; it is soft and relatively soluble
Which of the following sedimentary features would typically be found in shales but not in sandstones?
mud cracks
_____ is the most common type of chemical sedimentary rock
limestone
_____ is a form of calcium carbonate
travertine
Which one of the following is not a chemical sedimentary rock or evaporite?
shale
Which one of the following is not a type of limestone?
arkose
Oolitic Limestone is most likely to form in what type of depositional environment?
shallow, clear, marine
What is the chemical formula for dolomite, the major mineral in dolostones?
CaMg(CO3)2
Which of the following sedimentary features can each be used to determine paleocurrent directions?
ripple marks and cross stratification
Coal beds originate in_____
freshwater coastal swamps and bogs
Which characteristic is absolutely necessary for a sedimentary rock to have a potential as a possible reservoir rock for oil or gas?
high porosity
Non clastic textures are common in which of the following sedimentary rocks?
limestones
____ is not a part of the hydrologic cycle
Calcium Carbonate
Which one of the following statements is correct?
sea level drops when water is stored in expanding ice sheets and continental glaciers
Which of the following is the correct definition of stream gradient?
the drop in elevation of a stream divided by the distance the water travels
A natural, meandering, river channel is modified into a more or less straight and smooth, canal-like channel. Which of the following statements is correct?
the natural channel had a lower gradients and higher friction than the straight channel
How does urbanization (paving, etc) affect runoff and infiltration in a small, previously forested, drainage base?
infiltration decreases, runoff increases
Which of the following must result in a lower base level for rivers and streams?
sea level falls; land rises
______ make up the suspended loads of most rivers and streams
silt and clay-sized, detrital grains
____ describes the total sediment load transported by a stream
capacity
At the head of a delta, the major channel splits into smaller channels that follow different paths to the sea. These smaller channels are known as_____
distributaries
Why is a bird-foot delta like that of the present-day Mississippi below New Orleans likely to change naturally toward one with the shape of an equilateral triangle like the upper-case, Greek letter delta?
potential, new, major distributary channels have steeper gradients than existing channels
In the absence of cutoff, how does a river meander loop behave over time?
the gradient is lowered as the channel lengthens and migrates toward the cut or outer bank of the loop
A ___ stream pattern is developed only on growing mountains like volcanoes or where the land surface is tectonically doming upward
radial
A ____ stream patter develops on lands underlain by tilted or folded, alternating hard and soft, sedimentary strata.
trellis
_____ is an abandoned, cutoff, meander loop
an oxbow
______ are characteristics of downcutting streams and a youthful stage of valley evolution
rapids and lots of whitewater
Many larger rivers in the Colorado Plateau region meander in deep, narrow canyons and have no flood plains. How could this happen?
original, old age streams
A water gap is _____
a short segment of canyon
Which of the following is the only correct response concerning the location and causes of the extraordinarily sever, 1993, flooding on the Mississippi River and tributaries?
upper basin; very heavy sustained rainfall in the late spring and early summer
Which one of the following statements correctly describes how stream terraces can form?
a temporary base level is eliminated; the stream downcuts upstream form the old temp base level
______ are components of the hydrologic cycle that release water vapor directly to the atmosphere
evaporation and transpiration
What is the drop in water surface elevation divided by the distance the water flows?
stream gradient
The ____ river has the largest discharge of any in the world
amazon
Which one of the following does not apply to stream turbulence and average velocity?
laminar flow; dissolved load
Which one of the following is true concerning a major river system?
upstream tributaries usually have higher competencies than the major rivers
______ generally constitutes the highest percentage of the annual sediment load moved by a stream.
suspended load
Where is erosion concentrated along a meandering stream?
on the outer parts of the meandering loops or bends
Which one of the following would cause stream rejuvenation?
the land is uplifted
Which one of the following statements is true concerning natural levees?
mostly fine sand and silt that build up during a floor
In a ____ drainage pattern that is generally developed in areas underlain by tilted or folded strata, tributary streams flow along outcrop areas of the softer strata
trellis(folded)
A ____ drainage pattern is common in the Appalachian Valley and Ridge Province
trellis(AV/RP)
A stream begins at an elevation of 200 meters and flows a distance of 400 kilometers to the ocean? What is the average gradient?
0.5m/km
_____ in a delta are essentially cross strata inclined toward deeper water
foreset beds
The ____ describes the movement of water through Earth's hydrosphere
hydrologic circle
______ describes the particle transport mode in streams intermediate between suspension and rolling along the bottom
saltation
Which of the following features characterize wide streams and valleys?
natural levees; broad flood plains
Entrenched meanders are evidence for what sequence of geologic events?
land uplift was followed by stream downcutting
Which one of the following best describes how urbanization affects small-stream watersheds?
infiltration decreases; lag time between storms and peak runoff is shortened
A dam and reservoir are constructed on a graded river. What will happen?
deposition upstream from the sam; channel downcutting below