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Geol Final
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92
Geology
Undergraduate 1
12/10/2012

Additional Geology Flashcards

 


 

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Term
Isotopes of an element are atoms of the element but with
Definition
Different number of electrons
Term
The land plants evolved about
Definition
425million years ago
Term
the first timethat coalbeds apperared abundantlywas
Definition
166 million years ago
Term
the extinction of the dinosaurs occured about 
Definition
66 million years ago
Term
the shell bearing organismsfirst appeared about
Definition
570 million years ago
Term
currently the oldest terrestrial rock have an isotropic age of
Definition
3.8 billions years
Term
oxygen isotpoe method cannot be used to date geological materials because
Definition
all commonnatural isotopes of oxygen are stable
Term
the following mineral cannot be dated by the potassium-argon isotope method 
Definition
quartz
Term
the stable isotopes produced from decay of uranium isotopes are
Definition
lead isotopes
Term
carbon 14-isotope methodof datingis limitedto geological or archeological materials if they are younger than
Definition
20,000 years
Term
carbon-14 isotope age may not correspond to dates obtained from counting tree rings, because
Definition
neutron flex from the sun that has been nexessary to produce carbon-14 isotope in the past may not have been the same as that involved in recent times
Term
the third most abundant gas in our atmosphere is argon
Definition
potassium-40 isotope
Term
the following is produced from the decay of carbon-14
Definition
nitrogen-14
Term
a discomformity within a sequence of strata can be established
Definition
examining the fossil records
Term
the isotope methods of dating of terrestrial and extra-tessterial materials have established that the age of earth is
Definition
4.7 billion years old
Term
the ocean evolved about
Definition
3.8 billion years ago
Term
Earthquakes
Definition
Term
the speed of P-wave (or longitudinal wave) is a function of three variables
Definition
bulk modules, density, and modulos of rigidity
Term
the speed of the S-wave(or transverse wave) is a function of two variables
Definition
bulk modules and density
Term
the speed of S-waves at shallow levels within the earth is about 
Definition
4.5 km/sec
Term
the speed of the P-wave at shallow levles within the earth is about
Definition
8.6 km/sec
Term
the speed of surface waves is about
Definition
0.25 km/sec
Term
the order in which seismic waves arive at a fixed point is
Definition
P-wave,S-wave,Love wave
Term
which of the following seismic waves has a motion with half forward and then half backward on a vertical plane?
Definition
Rayleigh waves
Term
the epicenter of an earthquake can be determined from 
Definition
knowledge of arrivals of P and S waves recorded at different stations
Term
which of the following is a charchteristic of S waves
Definition
they do not travel through liquids
Term
the majority of earthquakes occure
Definition
at the boundaries of converging tectonic plates
Term
most earthquakes foci are located at 
Definition
shallow depths limited to about 70km
Term
earthquakes do not orginate within the lower mantle because
Definition
the rocks there are not rigid enough to store engery associated with deformation
Term
the richter scale reflects
Definition
the maximum ampliture (Expressed in mm) of S-waves that would have been recorded at a station about 100 km from the epicenter
Term
the richter scale change from2 to 4 describes
Definition
ground motion change by 100 times
Term
the maximum S-wave amplitude given in mm scale of a recorded earthquake by a standard seismometer at 100 km away from that epicenter, is converted to mgnitude(M) by the following realation
Definition
10M
Term
relative to an earthquake of magnitude 5 on the richter scale,an earthquake of mafnitude 7 releases 
Definition
about 20-30 times more energy
Term
ground acceleration, the rate of change of the horizontal or vertical velocity, during earthquaes is a useful piece of information for
Definition
designing buildings and other structures to withstand seismic shaking
Term
hoes constructed of adobe can fail or collapse undera horizontal acceleration,which causes most damages to buildings and other structures, as small as 
Definition
0.1g
Term
the frequency of an earthquake wave equals
Definition
the number of waves passing per second at a point of refrence
Term
low frequency seismic surface waves
Definition
may induce more damages to tall buildings than to short buildings
Term
low buildings tend to sustain the greatest damage near earthquake epicenters becasuse
Definition
highfrequency waves diminish more quickly with distance than do low frequency waves
Term
 in an earthquake prone region, the potential for a large magnitude earthquake is high where the subsurface rocks are
Definition
similar to mud
Term
the number of earthquakes per year with richter magnitude less than 3.5 is
Definition
1-2 million
Term
Rivers
Definition
Term
the steeprdy portion of stream longitudinal profile is located 
Definition
near the heardwaters
Term
stream competence is measured by
Definition
the largest particle size that the stream can transport in its bed load
Term
the discharge of a stream increases as
Definition
velocity,width, and depth increase
Term
active erosion in a meander takes place
Definition
along the outer bank of a bend
Term
flow around ia meander results in erosion on one break but deposition on the other bank marked by the formation of 
Definition
point bar
Term
after a trubutar has joined a major stream, the unified stream immeditatltedly below the conflunce must have 
Definition
highervelocity than the major stream
Term
the ration of dissolved chemical load ot sediment load in a stream may increase by
Definition
an increase in vefetation in the drainage basin
Term
which one of the following is the most abundant chemical group in major rivers of the world
Definition
calcium and bicarbonate
Term
the two most abundant dissolved chemical componets of river waters come essentially from dissolution of
Definition
limestone
Term
natural leeves form by 
Definition
deposition of coardse sediment as velocity decreases abruptl for water that spills over the banks
Term
an incised meander is an indication of 
Definition
a lowering of the base levle of erosion
Term
which of the following is an example of local or regional base level of erosion
Definition
a lake
Term
the construction of a dam across a river would casue
Definition
the river to produce more bank erosion downstream from the dam
Term
river terraces can be the resulf of 
Definition
periodicdrops in the base level of erosion
Term
a "misfit" river could be an indication that 
Definition
the river has been a victim of stream piracy. Also, a climate shift to a relatively drier condition has occured in the region.
Term
a braided channel develops due to
Definition
a decrease in discharge
Term
the floodplan development for urban growth leads to
Definition
frequent flooding from a decrease in the lag time between rain fall and cresting of the river
Term
a dendritic drainage pattern implies that 
Definition
the area is underlain by undeformed rocks that have nearly uniform resistance to erosion
Term
a trellis drainage patter implies that
Definition
the area is underlain by a sequence of hard and soft rocks that are highly folded
Term
distributaries are located in which part of a stream system
Definition
delta
Term
an extensive delta growth is influenced by
Definition
consierable uplifting of and havey rainfall in the drainage basin
Term
waters in most rivers in teh world are fresh waters with total dissolved solid contents of
Definition
less than 100 ppm
Term
total dissolved solids of global average river is 
Definition
110 ppm
Term
which of the following is not a major dissolved chemical componet of average river water
Definition
aluminum
Term
which of the following is the second msot abundant chemical componet of global riverwater
Definition
nirate
Term
which one is the right sequence in terms of the decrease in the relative size of the resorvoir
Definition
groundwater>lakes>soils>moisture>atmosphere>rivers=biosphere
Term
Ground Water
Definition
Term
the water table separates
Definition
the zone of aeration from the underlying zone of saturation
Term
ground water 
Definition
can move upward against the force of gravity
Term
a preched water table
Definition
occurs whenver there is a localized aquicludewithing an aquicfer
Term
karst topography is charchterized by
Definition
sinkholes
Term
artesian ground-water systems are charcterised by
Definition
 rise of water above the level of a confined aquifer if a well is drilled into the aquifer
Term
the water table near a large pumping well
Definition
assumes a cone of depression
Term
one of the following is alwasy a poor aquifer
Definition
granite
Term
the rate of flow of much of shallow ground water is generally on the order of 
Definition
centimeters or may be one or two meters per day
Term
hard water contains relatively large amounts of 
Definition
calcium and magnesium ions
Term
darcys law basically states that 
Definition
the volume of ground water flowing in a specified amount of time is proportional to the vertical drop in height of the water table between two points divided by the horizontal distance between the two points
Term
caves form n terrain or region where the rocks are essentially
Definition
limestone
Term
stalacities and stalagmites form as dropsof water from the ceiling of a cave
Definition
lose dissolved carbon dioxide by enteringinto the cave with the atmospheric air
Term
stalagmitesand stalagties are made up of 
Definition
calcite
Term
if an excessive pumping of ground water in a coastalarea lowers the water tableat a locality by 0.5 meters the contact between the fresh ground water and the salty ground water in the locality will
Definition
rise by 20 meters
Term
the leaning of the pisa tower in italy was caused by
Definition
consolidation of the ground material by rapid ground water depletion
Term
which rock type among the following would make the best aquifer
Definition
well sorted sandstone
Term
the permeability of a rock system depends on severalthings except
Definition
thickness of the rock system
Term
development of geyers requires that
Definition
the ground water partly be heated at a temperature above boiling and partly wiht a cap of a layer of coled water within a reservoir that offers limited convective mixing of the water
Term
the problem of liquefaction can be somewhat reduced by
Definition
compacting the soil as much as possible
Term
intraplate earthquakes of 1811-1812 in new madrid region near missouri are related
Definition
movement along an ancient rift zone
Term
seismic raps represent
Definition
a period of reduced or no seismic activity in the geologic record
Term
which of the following is an example of eathquake precursor
Definition
an increase and then shift to a decrease in the time of the first arrival of and induced P-wave from a fixed source to a various recording station
Term
liquefaction
Definition
transforms water-saturated granular material froma  solid to liquid state
Term
the hazard from a tsunami may be linked to 
Definition
a submarine normal faulting
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