Exam 3 Fall 2017 old test Flashcards
which soil and topography conditions will have the greatest infiltration rate
sandy soil and gentle slope
which of the following minerals is most likely to form a clay mineral during weathering
feldspar (KAlSi3O8)
goes through hydrolysis
what information do geologists use to estimate speeds of ancient rivers
grain size
what is predominant physical weathering process on Stone Mountain
exfoliation
one of the most effective mechanisms for physical weathering is
frost wedging
what is the difference between a rockslide and a rock avalanche
in a rockslide, the rocks move more or less as a unit; in a rock avalanche, the rocks move independently like a fluid
in what type of rock do most caves form
limestone
chemical stability is
a measure of a substance’s tendency to remain chemically inert
stalagmites
grow up from the floor of a cave
a drainage divide is a
topographic high that separates stream systems
acids enhance chemical weathering; what is the most common natural acid on the earth’s surface
carbonic acid
why are sand-sized particles easier to erode than clay sized particles
because clay particles are attracted to one another because of opposite charges, which hold them in place
which of the following will decrease the rate of chemical weathering of a rock at the earth’s surface
decreasing the temperature
telephone poles that lean slightly downhill are a likely result of which of the following processes
creep
suspended load includes all materail
temporarily or permanently suspended in the flow
which of the following minerals will have the greatest chemical stability
a mineral with a low solubility and a low rate of dissolution
where do deltas form
at river mouths
which of the following slopes of unconsolidated material will be the least stable
a slope greater than the angle of repose
if stream a and stream b flow together to form stream c then what must be true regarding stream c
stream discharge is greater than in A or B
pedocal soils
are characterized by little leaching, scant humus; form in arid (dry) climates; have abundant calcium carbonate nodules; all of the above
the main difference between a hot spring and a geyser lie sin the
regularity of the underground plumbing system
on a delta, smaller rivers that branch off downstream are called
distributaries
which of the following combinations make for the best groundwater reservoir
high permeability and high porosity
if a groundwater well is pumped for a long period of time it forms a
cone of depression
potholes in bedrock of riverbeds form by
abrasion
which of the following terms describes the total sediment load carried by a stream
capacity
the process by which surface water becomes groundwater is called
infiltration
two wells (A and B) are drilled into rocks that have the same porosity, but the rocks around well A have a higher permeability than those around well B; suppose both wells are pumped at the same rate; what statement is true
Well A will have a larger cone of depression
which of the following is characteristic of soil horizons
they are classified by assigned letters; they can be distinguished from one another by appearance and chemical composition; boundaries between soil horizons are usually transitional rather than sharp; all of the above
as a rock breaks into smaller pieces, the ration of surface area to volume
increases
what happens to the volume of water that passes from groundwater to streams during a prolonged drought
it decreases
what type of aquifer is bounded above and below by relatively impermeable beds
confined
the process whereby streams break apart and erode rock is called
abrasion
what is the difference between the saturated and unsaturated zones of groundwater
the pore spaces in the saturated zone are full of water; the pore spaces in the unsaturated zone are not full of water
which of the following minerals is most susceptible to oxidation
pyroxene (MgFeSi2O6) because of the iron
laterite soils, also known as oxisols, are characterized by
intense leaching with accumulations of iron and aluminum oxides
organic matter in the earth’s topsoil is called
humus
an imaginary line below which a stream cannot erode is called
base level
Assume a region receives plentiful rainfall and is underlain by an open aquifer composed of sand and gravel. Predict what is the best representation of the relationship between topography and water table
the water table will follow the slope of the land
If a dam is build, sediment will ______ on the upstream side of the dame and sediment will ______ on the downstream side of the dam
accumulate
erod
which of the following terms describes a curved, coarse-grained deposit that forms on the inside curve of a stream
point bar
because of the undercutting action, waterfalls
retreat upstream
a farmer drilled a well into an open aquifer compose of sand and gravel. He installed a septic system downslope from the drinking well. A few years later the septic system started to leak. Water tests showed that the well water was clean and uncontaminated by the bacteria in the septic system. Why did the septic system not contaminate the drinking water?
the groundwater flow carried water away from the well
which of the following processes is not an example of chemical weathering
splitting of a rock along a fracture
which soil horizon consists primarily of slightly altered, weathered bedrock
the C horizon
which of the following minerals is most stable at the earth’s surface
hematite (Fe2O2)
if rain falls on a gentle slope, which scenario will increase recharge of an unconfined (open) aquifer
heavy rain on sand
which of the following statements about groundwater in coastal regions is TRUE
seawater is denser than fresh water; therefor, fresh groundwater floats on top of salty groundwater
physical weathering is greatest at
high latitudes
when a meandering stream eventually cuts off the meander then it forms an
oxbow lake
because of human activity, sediment transported by streams has
increased dramatically
soil with approximately equal proportions of sand, silt, and clay along with generous amounts of organic matter is called
loam
which of the following rocks would be most affected by chemical weathering
limestone
which of the following statements regarding floods is true
a 50 year flood has a 2% chance of occurring in any one year
which of the following processes describes the general downhill movement of rock, soil, or unconsolidated materials under the influence of gravity
mass wasting
discharge is expressed in units of
m^3/sec
sinkholes are a possible danger to regions underlain by what type of bedrock
limestone
a stream channel is narrowed by bridge construction. How will the velocity of flow change if the depth and discharge of the stream remain constant
velocity will increase
what powers the hydrologic cycle
solar energy
which location would have the potential for the best groundwater production
the area that is downhill and is made of sand and gravel
kaolinite (Al2Si2O5(OH)4) weathers to gibbsite (Al(OH)3) through the process of
hydrolysis
the accumulation of rocks at the base of a cliff is called
talus
which of the following represents the boundary between the saturated zone and the unsaturated zone
groundwater table
a rapidly growing city within a humid climate zone experiences a land use change from predominantly crop land to mostly urban/suburban. A likely natural response would be
reduced infiltration and increased flooding
which of the following minerals is least stable at the least stable at the earth’s surface
olivine ((MgFe)2SiO4)
______ is the infiltration of water into the saturated zone, and ______ is the exit of groundwater to the surface
recharge
discharge
layers that are impervious to groundwater flow are called
aquicludes
what causes the deep red color of soils found in Georgia and other warm, humid regions
iron oxides
how would the amount of rainfall change on the opposite side of a mountain from the ocean if that mountain was eroded down
rainfall would increase
four stream gauging station locations are shown on the map; Assume the bedrock and topography is similar for each stream system; Predict which station will record the greatest discharge
D because it is at the end of a very long river
what sort of sedimentary structure forms where rivers run into bodies of standing water
delta
curves and bends in a stream channel are called
meanders
according to Darcy’s law, which of the following aquifers will have the greatest rate of groundwater flow
an aquifer with high hydraulic conductivity and a high hydraulic gradient
the town of Pleasantville is located at a meander bend in a floodplain. In order to reduce the threat of property loss due to erosion, Pleasantville’s engineer proposes the construction of the diversion structure. Along the course of the diversion, the stream gradient will be _______ than the gradient along the existing meander bend
greater
which of the following is considered part of a stream’s bed load
gravel sliding along the bottom
in a soil profile, organic matter is found
primarily in the A horizon
has lots of sinkholes
karst topography
has random drainage pattern
dendritic
has angular joints of drainage
rectangular
is similar looking to rectangular but flows between structures
trellis
