Final Flashcards
Lithification involves _______ & _______
Compaction & cementation
Sandstone and shale are what type of sedimentary rock?
Clastic
As compared to coarse-grained igneous rocks, all fine-grained igneous rocks _____________
Cool and solidify more quickly
The magnetic field of Earth in the geologic past is _____________
Known to have experienced numerous polarity reversals, due to remnant magnetization of iron-rich minerals in rocks.
In silicate minerals, tetrahedra may be linked to form _____________
long one- dimensional chains, extensive two-dimensional chains, massive three-dimensional frameworks
Sea-floor spreading is driven by volcanic activity _____________
along mid-oven ridges
Slab pull occurs because sub ducting slabs are _____________
cooler, and therefore more dense, than surrounding asthenosphere.
Viscosity depends on _____________
Volatile content,
temperature,
silica content.
If a body of magma becomes more felsic, its viscosity will _____________
increase
In agreement with the Big Bang theory, our Universe is _____________
expanding
If you determine the composition of an igneous rock, you can deduce a number of things about the rocks origin. Which is NOT one of those things?
the exact age
If you determine the composition of an igneous rock, you can deduce a number of things about the rocks origin. What are those things?
the rate at which it cooled, t
he original source of the magma,
the environment in which it was found.
Hot-spot volcanoes _____________
May arise in the interior of lithosphere plates,
can arise on continents,
can arise from the ocean floor.
An example of a continental volcanic arc
the Andes Mountains
The best estimate of the Universe is _____________ old
14 billion years.
The most common minerals within Earth are _____________
Silicates
When in contact with hydrochloric acid, which mineral gives off bubbles of carbon dioxide gas?
Calcite
Whether an eruption will primarily produce lava flows or pyroclastic debris is influenced by the _____________
Proportion of volatiles within the lava,
composition of the lava,
viscosity of the lava
Is petroleum a mineral?
No because a liquid
Is cubic zirconia mineral?
No because it’s a synthetic diamond substitute that is not found in nature
Basaltic laves _____________
Contains more iron and magnesium than rhyolitic lavas.
Which type of magma has the greatest silica content ?
Felsic
Under the theory of plate tectonics, the plates themselves are _____________
Discrete pieces of lithosphere at the surface of the solid Earth that move with respect to one another.
Deep-oceanic trenches are feature of _____________-plate boundaries
Convergent
Pillow lavas are associated with _____________
submarine basaltic eruptions.
The greatest hazard to human life associated with volcanoes is _____________
pyroclastic flows
As compared to aphanitic igneous rocks, phaneritic rocks are _____________
Made of crystals big enough to see
Marine magnetic anomalies result from sea0floor spreading in conjunction with _____________
Magnetic polarity reversals
Currently, most geologist agree that continental drift occurs;
the mechanisms that drive drift are at work in the ocean basins and upper mantle and were unknown in Wegener’s time.
In Wegener’s evidence for continental drift, continents were proposed to fit together, such as the east coast of South America with the _____________ and the upper west coast of Africa with the _____________
lower west coast of Africa; east coast of North America
The lithosphere is composed of the _____________
crust and the uppermost part of the mantle.
Aside from Earth, terrestrial planets are _____________
Mars, Mercury, and Venus
In our current understanding of the Big Bang _____________
the Universe is considerably older than Earth
At a subduction zone, the overriding plate _____________
may be composed of either oceanic or continental lithosphere.
The difference between magma and lava is _____________
that magma is found beneath the surface, whereas lava is found at the surface.
Atoms that are heavier than iron are generally produced by _____________
explosions of supernovas.
Earth’s magnetic field is generated by _____________
flow of the liquid outer core
Iceland is formed where it is today because of the presence of _____________
the mid-Atlantic ridge and a hot spot
Bombs, ash, and cinders are all examples of _____________
pyroclastic debris
Every plate boundary can be recognized by _____________
the presence of an earthquake belt
At transform-plate boundaries _____________
earthquakes are common but volcanos are not.
Due to fractional crystallization and assimilation of surrounding host rock, most magmas that rise slowly through the crust chemically evolve to become _____________
more felsic
Nonviolent eruptions characterized by extensive flows of basaltic lava are termed
effusive
A sill is a _____________
Sheet-like intrusion that lies parallel to the surrounding layers of sedimentary rock.
In the whole Earth, the four most common elements are oxygen, silicon, magnesium, and _____________
iron
Mt. Kilimanjaro and the Basin and Range Province are the results of _____________
rifting
In 79 C.E., the citizens of Pompeii in the Roman Empire were buried by pyroclastic debris derived from an eruption of _____________
Mt. Vesuvius
True or false: Multiple properties must be used to diagnose a mineral.
True
Within the terminology of plate tectonics, an active margin is _____________
a continental coastline that coincides with a plate boundary.
Strong evidence that the Universe is expanding comes from the fact that the light emitted from distant galaxies appears to be _____________
red shifted
A fast-moving flow consisting of a mixture of water and volcaniclastic debris is called a _____________
lahar
The cleavage in minerals refers to _____________
a tendency to break along planes of weakness
Important volatiles in magmas include _____________
water and carbon dioxide
A famous example of hot-spot volcanism occurs at _____________
the island of Hawaii
The east coast of the North American continent is a _____________ margin
passive
Parts of the process that leads to the exhumation of metamorphic rocks
Continents squeezing together,
mountain belt collapsing,
erosion
A body of gneiss is subjected to head and forms a melt. Later the melt cools and crystallizes to form a _____________
igneous rock
Braided stream _____________
consist of a series of intertwined channels that are overloaded with sediment.
The protolith subjected to metamorphism _____________
may belong to any of the three primary rock types.
Thermal (contact) metamorphism occurs _____________
in areas surrounding igneous intrusions
Grains become rounded primarily during _____________
transportation
Pumping vast quantities of water locally _____________
lowers the local water table, forming a cone-snapped depression.
A buried body of shale is subjected ti differential stress, causing clay minerals to realign and produce slate; this is an example of _____________
Metamorphism
The removal of detritus from weathered rock aran outcrop is termed _____________
Erosion
Which type of metamorphism affects the greatest volume of rock?
Dynamothermal metamorphism
When limestone becomes chemically altered so that half of the calcium atoms are replaced by magnesium, the resultant rock is termed _____________
dolostone
Lithified detritus (breakdown products of preexisting rocks) forms which kind of sedimentary rock?
Clastic
Chemical and biological rocks are classified primarily on the basis of _____________
mineral composition
What processes can occur in the formation of metamorphic rock?
- Realignment of minerals so that they can develop a preferred orientation
- Segregation of minerals so that they develop a preferred orientation.
- Solid-state rearrangement of atoms or ions to create a new assemblage of minerals.
Where would Gneiss be found?
continental collision
Exhumation
Bringing things to the surface. trust faults, erosion.??
Where is crust thinnest ?
Mid-ocean ridges
Slab pull
Sinking slab is cold and subduct in a subduction zone
The mantle is _____________
Solid: it’s just so hot that it actually flows
Hawaii is on the _____________
Pacific plate.
San Andres is a _____________ plate boundary
Transformative
What processes can NOT occur in the formation of metamorphic rock?
complete remelting of the rock, followed by solidification to form a new rock.
Metamorphic rocks from lowest to highest grain
slate, phyllite, schist, gneiss
Which environment would most likely produce sedimentary deposits characterized by poorly to moderately sorted, angular to sub angular grains that consist of feldspar, quartz, and lithics (rock fragments)?
Alluvial fan
True or False: Meteorite impacts have been known to induce metamorphism of sediments and rocks
true
_____________ commonly serves as a protolith in the formation of slate
Shale
Perched water tables occur _____________
above the regional water table, with in permeable rock or sediment.
If water the transport mechanism of sediment, the grain size of sedimentary deposits most closely indicates the _____________
velocity of the water at the moment the sediment settled to the bottom.
Metamorphism may be induced by _____________
- contact with a hot pluton
- contact with hot groundwater
- heat and pressure associated with deep burial
If a material is porous, it _____________
may be permeable or impermeable
An impermeable layer of rock or sediment is termed a(n) _____________ in hydrogeologic contexts
aquitard
Foliated metamorphic rocks posses _____________
a planar fabric consisting of mineral grains in preferred orientations or preferred patterns of association (banding)
Slaty cleavage, schistosity, and compositional banding are all examples of _____________
foliation
Glacial tilt is composed of _____________ sized particles
clay-to boulder-
Compaction and cementation of grains occurs during _____________
lithification
Extensive pumping of fresh groundwater from wells near a seacoast is most likely to induce _____________
saline intrusion; with time the well will start to deliver saline water
The primary stream fed by tributaries within a drainage basin is termed a _____________
Trunk stream
Because the velocity of sediment settling (deposition) is positively related to grain size for waterborne sediments, fluvial deposits are more likely than glacial deposits to _____________
be well sorted
Graded beds tell a geologist that a _____________
turbidity current deposited these beds, depositing coarser material first.
Ephemeral streams_____________
have flowing water either episodically or during a portion of the year.
A well-sorted sediment will have _____________ porosity than a poorly sorted sediment.
greater
The preexisting rock that is subsequently altered to form a metamorphic rock is termed a _____________
protolith
A periodic explosive eruption of steam and water from within the ground up through the surface is termed a _____________
geyser
Two major sources of energy, coal and oil shale, are considered _____________ sedimentary rocks
Organic
Land subsidence is likely when _____________
discharge lowers the water table
Dissolution of rock produces _____________
secondary porosity
Metamorphism, in broadest terms, involves _____________
Changes in mineralogy and texture in response to heat and stress
_____________ commonly serves as a protolith in the formation of marble.
Limestone
A meander that is cut off to become completely isolated from the main channel, but that retains water, is a(n) _____________
Oxbow lake
Within a meander, where is sediment most likely to be deposited?
On the inner bank (point bar) of the meander
An artesian well is one that _____________
discharges groundwater at ground surface without pumping.
Physical precipitation of gypsum due ti evaporation of seawater produces which kind of sedimentary rock?
Chemical
Compared to low-grade metamorphic rocks, high grade-rocks _____________
are produced at greater temperatures and pressures
The blueschist facies is a metamorphic realm of _____________
high pressure but relatively low temperature.
In the region immediately surrounding an isolated volcano, a _____________ drainage network is expected.
radial
The breakdown of exposed rock into small fragments and dissolved ions is termed _____________
weathering
_____________ commonly serves as a protolith for quartzite.
sandstone
What does the lack of foliation mean in a metamorphic rock?
That the rock formed in an environment free of compression or shear.
The development of a preferred orientation of large, flaky mica crystals within metamorphic rock is termed _____________
Schistosity
Which transport medium carries the largest particles?
ice
The elevation of the water table _____________
may rise during rainy periods and sink during droughts.
Ripples, dunes, and cross bedding are sedimentary structures that can be used to help determine _____________
- wind direction
- past events
- current direction
An aquifer that is isolated from the Earth’s surface by an aquitard is _____________
confined aquifer.
Chemical weathering takes place most rapidly in environments that are _____________ and _____________
Warm; wet
The inner edge of a meander, where sediment is deposited, is a(n) _____________
Point bar
Stratification refers to _____________.
The development of layering within sedimentary rocks
The majority of liquid freshwater within Earth exists in _____________
Pores within rock and sediment
Meandering streams _____________
Have a channel that is highly sinuous (curvy)
True or False: A dry well will always result whenever the base of the well is above the water table.
true
Differential stress will cause crystals to align in preferred orientation unless the crystals are _____________
equant
The flat-lying area surrounding a river channel is termed the _____________
floodplain
Primary porosity may be reduced by _____________
The compaction and cementation of grains
The outer edge of a meander, where mineral is being eroded, is a(n) _____________
Cut bank
Cemented shells or marine organisms form which kind of sedimentary rock?
biochemical
Clastic sedimentary rocks are primarily classified on the basis of _____________
grain size
Two common metamorphic rocks that typically lack foliation are _____________ and _____________
quarzite; marble
Dynamothermal (regional) metamorphism occurs when _____________
Rock becomes buried deeply during continental collision and mountain building.
What principle allows geologists to deduce the folds in beds occurred after deposition?
Principle of original horizontally
A body of rock affected by tensile stress will likely undergo _____________
stretching
Orogenesis (Mountain building) leads to the production of _____________
Any of the rock types
According to the moment magnitude scale (Mw)- a magnitude 8 earthquake results in 1,000 times greater amplitude than a magnitude _____________ earthquake
5
What geologic setting(s) would you expect to produce seismic activity?
- rift valley
- basin
- collisional mountain belt
Right lateral and left lateral are both examples of _____________ faults
strike-slip
In an unweathered sample of igneous rock, the ratio of an unstable isotope to its stable daughter isotope is 1/15. If no daughters were present at the time the rock cooled below closure temperature, and the half-life of the reaction is 50 million years, how old is the rock?
200 million years
Regions of continents that have not been subjected to orogeny during the past one billion years are termed _____________
cratons
True or false: If the numerical ages of two formations are known, then the relative age of each with respect to one another can be inferred.
true
Normal, reverse, and thrust are all examples of _____________ faults
dip-slip
Regions where Precambrian metamorphic rocks are exposed at the surface are termed _____________
shields
Which portion of a radioactive isotope is expected to remain in an unaltered (unreacted) state after the passage of three half-lives?
one-eigth
An episode of mountain building is termed a(n) _____________
orogeny
The central portion of high curvature on a fold is termed the fold _____________
hinge
A surface along which rock on opposed sides is offset by earthquake-induced slip is called a _____________
fault
Buried erosional surfaces between parallel sedimentary strata are termed _____________
Disconformities
Periods of intermittent sliding on a fault as a result of the release of stress during episodes of displacement, followed by stress buildup to the point that the fault is reactivated, is termed _____________
Stick-slip behavior
The point within Earth where an earthquake take place is termed the _____________
hypocenter (focus0
In the area immediately surrounding an igneous intrusion, a host limestone is locally metamorphosed to produce marble. The limestone must be _____________
older than the marble.
Why were geologists able to switch from determining relative age of geologic events to determining the numerical age?
Radioactivity was discovered.
A tsunami is _____________
An earthquake-generated sea wave that can sometimes destroy coastal cities thousands of kilometers from its source.
Medium- and deep-focus earthquakes occur along _____________
convergent-plate boundaries only
Earthquakes the occur in a band called a _____________ cane used to track the motion of subducted oceanic lithosphere.
Wadati-Benioof zone
The sides of a fold, where curvature is at a minimum, are termed?
limbs
Mt. Everest, the tallest mountain above sea level, is located on the continent of _____________
Asia
A fold shaped like an elongated arch is a(n) _____________
Anticline
As a seismologist examining a seismogram, you would know that the third set of waves displayed _____________
would cause the most damage
Summary of the geologic time scale development
Relative ages for sedimentary strata were known well before accurate numerical dates for these rocks could be provided.
In a _____________ fault, the fault plane is less that 30* from horizontal and the the hanging-wall block moves upward relative to the footwall block.
Thrust
Movement along faults often produces sharply angular rock fragments termed _____________
Fault Breccia
_____________ may help a geologist recognize a fault.
- Displacement
- Fault scraps
- Breccia
What must occur for the elevation of a mountain range to increase overtime?
The rate of erosion must be less than the rate of uplift.
Which earthquake intensity scale assess the effects of an earthquake on humans and human -made structures?
Mercalli scale
The distinction between joints and faults is that _____________
Faults are fractures along which displacement has occurred; displacement does not occur along joints
It is possible for offset along an oblique-slip fault to have both _____________ and _____________ components
right-lateral; left-lateral
If during an earthquake, a hanging wall slides upward relative ti a footwall, the fault is termed _____________ if the fault is steep (closer to vertical than horizontal)
Strike-slip
Surface waves _____________
Produce the most of the damage to buildings during earthquakes.
Faulting and earthquakes are examples of _____________
brittle behavior
Uniformitarianism is succinctly summarized by the phrase _____________
The present is the key to the past
At any point along the fault plane surface of an oblique (non vertical) fault, the _____________
hanging wall lies vertically above the footwall
Two atoms of a single element that differ in number of neutrons are said to represent two distinct _____________ of that element
isotopes
The quantity of offset that occurs along a fault is termed _____________
displacement
Which eon of geologic time is represented by rocks containing abundant shelly fossils?
Phanerozoic
In an undisturbed sequence of sedimentary rocks, younger layers overlay older layers, according to the principle of _____________
Superposition
How many seismic stations are necessary to find the epicenter of an earthquake?
3
Earthquakes are likely to occur
on all plate boundaries
The key to finding the location of an earthquake’s epicenter is measuring the _____________
difference between the time that the P-wave arrives and the time that the S-wave arrives at the seismometer station.
A hot brittle of rock is more likely to exhibit _____________ than is a cold body of rock.
Ductile behavior
Which type of seismic waves has the highest velocity?
P-wave
The surface below sedimentary rocks that overlie igneous or metamorphic rocks is termed a(n) _____________
Nonconformity
Short-term predictions of earthquake behavior _____________
have been largely unreliable
Force per unit is termed
Stress
Day after tomorrow
- Plunging the northern hemisphere into a ice age.
- Ocean conveyor
- Thermohaline circulation –ANSWER
Is the mantle solid or liquid?
Solid
Which 2 tectonic plates are located near Hawaii
NONE OF THE ABOVE
2012 - What would be the premise
Neutrinos make the mantle boil, leading to plate tectonics on steroids, out run yellow stone eruption in a Winnebago.
2012- What kind of waves did LA have
R-waves
10.5 movie - How are they going to stop the giant earthquakes?
More nukes
The largest contribution to total radiative forcing is caused by the _____________
increase in the atmospheric concentration of CO2 since 1750
_____________ are the biggest influence on global warming
Humans
Sea level has risen _____________ centimeters in the 20th century
17
Sea level is predicted to rise _____________ centimeters in the next 25-50 years.
31
Dating and studying annual tree rings is termed _____________
Dendrochronology
Causes fo cimate change
- Variations in Insolation
- Changes in the atmosphere
- Changes in the ocean
- Changes in landmasses
Eras are divided into _____________
periods
The Principle of Uniformitarianism was articulated by _____________
James Hutton
Creator of Plate tectonics
Wegener
True or False: Earthquakes are randomly distributed over Earth’s surface
False
Idea that Earth and the solar system formed from a condensing cloud of gas and dust is the
Nebular hypothesis
Limestone is a _____________ sedimentary rock
biochemical
Common cement in clastic sedimentary rocks
Calcite
Biogeochemical cycles involve
chemical fluxes between living and nonliving matter.
What is not a sedimentary depositional environment ?
Batholith
The hydrologic cycle consists
of water in motion between biological (organisms) and physical (oceans, atmosphere, surface water, groundwater, ice caps, glaciers, soils, etc.) reservoirs.
In the carbon cycle,
carbon transfers between several near-surface reservoirs, including the ocean, the atmosphere, organisms (living and dead), and rocks.
Paleoclimates: ice-cores
Bubbles trapped in ice cores preserve the chemical composition of the atmosphere at the time the ice formed. Ice cores contain annual layers that can be readily dated.
Three conditions are necessary to form a glacier.
- A cold local climate (which requires polar latitudes or a high-elevation).
- Snow must accumulate; more snow must fall than melts.
- Snow must not be removed by avalanches or wind.
Snow compacts and melts to form _____________ , which recrystallizes into ice. Crystal size increases with depth.
firn
Under a microscope, glacial ice has _____________ grains and contains air bubbles. Air content decreases with age and degree of metamorphism.
coarse
Cirque glaciers
fill mountain top bowls.
Valley glaciers
flow like rivers down valleys.
Mountain ice caps
cover peaks and ridges.
Piedmont glaciers
spread out at the end of a valley.
_____________ often takes place where the glacier bends while flowing over steps or ridges in its substrate.
Cracking
The equilibrium line
separates the zone of accumulation from the zone of ablation.
In reference to glaciers, the position of the ______ represents a balance between addition by accumulation and loss by ablation.
toe
If accumulation exceeds ablation, the glacier ________, the toe moves farther downvalley, and the ice thickens.
advances
Glacial retreat
If ablation exceeds accumulation, the glacier retreats and thins. The toe moves upvalley, even though ice continues to flow toward the toe.
Tidewater glaciers are
glaciers that terminate in the ocean.
Continental glaciers entering the sea form broad, flat sheets called _________.
ice shelves.
________ form when the leading edge of a tidewater glacier or ice shelf breaks away (calves).
Icebergs
If a floating mass of ice is at least 6 m above the water and > 15 m long, it is formally called an ________
iceberg
Glacial erosion produces
deep, steep-sided valleys and jagged, knife-edged ridges and pointed spires.
During glaciation,
the valleys fill with ice and are aggressively eroded and oversteepened.
After glaciation,
the landscape is transformed, containing U-shaped valleys, hanging valleys, cirques, arêtes, horns, and other evidence of the erosive power of glaciers.
A horn is a pointed mountain peak formed by __________
three or more cirques that coalesce.
An arête is a
knife-edge ridge formed by two cirques that have eroded toward one another.
A cirque is a
bowl-shaped basin formed at the uppermost portion of a glacial valley. Aggressive freeze-thaw chews into the cirque headwall.
After the ice melts, a cirque is often filled with a _____ lake.
tarn
A hanging valley results
from the intersection of a tributary glacier with a trunk glacier.
The larger trunk glacier incises much deeper into the bedrock than the smaller tributary glacier. When the ice melts, the troughs have different elevations and a waterfall results.
A hanging valley
Medial moraines occur in the
middle of a valley glacier and result from merging of two lateral moraines.
Lateral moraines form
along either side of a valley glacier.
glacial drift
Sediment derived from glaciation. Drift may be stratified, indicating transport by water, or unstratified when deposited directly by the ice.
Glacial drift includes:
glacial till, erratics, glacial marine sediments, glacial outwash, loess, and glacial lake-bed sediment.
Glacial till is
- unsorted, unstratified sediment dropped by glacial ice. Till is made up of all grain sizes, from boulders to clay.
- Till accumulates beneath glacial ice, at the toe of a glacier, and along glacial flanks.
Glacial outwash is
sediment transported by meltwater.
Outwash is dominated by
sand and gravel that have had the muds removed. Grains are graded and stratified, abraded, and rounded.
Loess (pronounced “luss”)
is wind-transported silt. Glaciers produce abundant amounts of fine sediment, which is picked up and carried downwind.
Glacial lakes accumulate
fine rock flour that settles out of suspension in deep lakes.
Glacial lake sediments often display seasonal ______ layers that reflect the finest silt and clay from frozen winter months interlayered with coarser silt and sand from summer months.
varve
Ice sheets depress the lithosphere into the mantle. This process of ice loading and crustal lowering is called
______________
subsidence.
_____________ returns water to the oceans and sea level rises
Deglaciation
Glacial rebound occurs
after ice melts, the depressed lithosphere rebounds, and the land rises.
In polar latitudes with mean annual temperature less than -5 ºC, soil moisture and groundwater freeze, forming ____
permafrost.
The upper few meters of permafrost may thaw in summers, then re-freeze in winters, creating a distinctive landscape called ____________
patterned ground.
Milankovitch hypothesized
that climate variation over 100 to 300 Ka is predicted by cyclic changes in orbital geometry.
- axis wobble
- angle of rotation
- shape of Earth’s orbit
Minerals have a specialized geologic definition:
naturally occurring (mostly) inorganic crystalline solid formed by geologic processes definite chemical composition
