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196 Cards in this Set
- Front
- Back
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Definition of geology |
Scientific study of the solid party of Earth |
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Reasons for studying geology |
1. geologic hazards
2. natural earth resources
3. environmental issues
4. basic curiosity about the earth |
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Definition of the Big Bang |
cataclysmic explosion of infinitely small point that occurred 10-15 billion years ago and resulting in creation of all matter and the expanding universe |
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Nuclear fusion |
several hydrogen atoms combine to create helium |
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How do we know the details of the Big Bang theory? |
1. expanding universe with Doppler effect...stars are showing "redshift", moving away
2. Date of big bang...farthest observable stars are 15 billion light years away
3. early events reflect those that happen still |
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How did we get from initial atmosphere to current atmosphere? (3 things) |
1. hydrogen and helium escaped into outer space
2. volcanic eruptions
3. photosynthesis created oxygen |
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What are the origins of earth's hydrosphere? |
volcanic eruptions and comets |
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How do we know the information of Earth's layers? |
crust is directly sampled
study earthquake waves
lab experiments
study of meteorites |
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Sequence of events:
First stars form Our solar system forms Big Bang explosion Milky Way galaxy forms |
1. Big bang
2. first stars form
3. Milky Way forms
4. our solar system forms |
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Definition of a mineral (5 things) |
Naturally occurring
inorganic
solid
definable chemical composition
crystal structure |
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What is the definitive way to identify minerals? |
define chemical composition and crystal structure |
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What are the 4 physical properties of minerals? |
color, crystal shape, cleavage, reaction to acid |
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Definition of asbestos |
group of highly fibrous silicate minerals that are flexible, strong and heat resistant |
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What is the size, shape and arrangement of mineral grains? |
texture |
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Typical texture of each type of rock |
Igneous = interlocking
Sedimentary = cemented
Metamorphic = foliated |
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Three types of sedimentary rock |
clastic
chemical
carbonate |
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Silica tetrahedron |
silica atom surrounded by four oxygen atoms |
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What distinguishes a mineral from a rock? |
Mineral = atoms are in an orderly arrangement
Rock = hard, consolidated aggregate of mineral grains |
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4 types of clastic rocks |
conglomerate
sandstone
siltstone
mudstone/shale |
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2 types of carbonate rocks |
limestone
dolomite |
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Which kind of sedimentary rocks typically contain fossils? |
carbonate |
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Igneous rocks form by... |
solidification of molten rock as it cools |
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What does the grain size of igneous rock depend on? |
cooling rate |
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Extrusive igneous formations |
lava flows and ash fall |
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Intrusive igneous formations |
dike (cuts across layers)
sill (lies along layers)
pluton (irregular shape) |
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3 foliated metamorphic rocks |
slate, schist, gneiss |
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2 non-foliated metamorphic rocks |
marble, quartzite |
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What is the concept that Earth is very old and geologic features took a long time to develop? |
geologic time |
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Principle of Uniformitarianism |
present physical processes also operated in geologic past
"present is key to the past" |
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What is radiometric age dating? |
laboratory measurements of isotopes in rock that give age of rock in years |
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Age of EArth |
around 4.6 billion years |
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Principle that says as you move upward through sequence of sedimentary rocks, age becomes younger |
principle of superposition |
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principle that says although sedimentary rocks sometimes have inclined layering, they began with horizontal layering because sediment accumulates in horizontal layers |
principle of original horizontality |
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principle that says if igneous intrusion cuts across rock layers, intrusion is younger than rock layers |
principle of cross-cutting relations |
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What is an unconformity? |
surface between rock layers where erosion or non-deposition of rock has occured |
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Which rock is most useful for using radiometric dating? |
Igneous |
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Which rock is most difficult to date using radiometric dating? |
sedimentary |
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largest block of time of earth's history |
PreCambrian |
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What happened at the Paleozoic/Mesozoic boundary? |
mass extinction |
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time of the dinosaurs |
Mesozoic |
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What happened at the mesozoic/cenozoic boundary? |
extinction of dinosaurs |
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max number of half lives you can measure |
11 |
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what is a half life? |
time it takes for 50% of parent isotopes to decay |
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What are the possible causes of a dinosaur extinction? |
impact of a large meteorite/asteroid
volcanic eruption |
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What are some general causes of mass extinction? |
disruption of food chain
change in climate |
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How do we know details of asteroid impact model? |
evidence of clay layer
impact crater in Mexico |
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What are the top sources of the world's energy? |
1. oil and natural gas 2. coal 3. biomass and waste 4. nuclear fission
all are nonrenewable except biomass |
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What could happen after strip mining of coal? |
Acid runoff |
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Estimates for the age of Earth are much younger than the actual age of the Earth because... |
unconformities occur at the Grand Canyon |
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Which volcano is the least deadly? |
Kilauea |
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Origin is derived from what? |
remains of plankton |
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What is an oil trap? |
folded or bent rock layers with source rock on bottom, then reservoir rock, then impermeable seal rock |
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What two processes have allowed for oil production from impermeable source rocks? |
directional/horizontal drilling
hydraulic fracturing |
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Two methods of coal extraction |
strip mines
underground mines |
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Which has more environmental problems, coal or oil? |
coal |
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More water is polluted by... |
careless disposal of used oil |
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greenhouse gases |
CO2, H20 vapor, methane, chlorofluorocarbon |
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What two things have caused steady abundance of carbon dioxide in Earth's atmosphere? |
fossil fuel combustion
deforestation |
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What kind of volcano produces lava flows? |
Non explosive |
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What kind of volcano produces pyroclastic debris? |
explosive volcanoes |
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_______________ content controls magma viscosity |
Silica |
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In silica rich magma, _____________ occurs
In silica poor magma, _______________ occurs |
explosive eruptions
lava flows |
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Non explosive volcanoes occur where tectonic plates move... |
apart |
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Shield volcanoes are made of... |
basalt |
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Two kinds of explosive eruptions |
ash-fall eruptions
ash-flow eruptions
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Mt. Vesuvius and Mt. St. Helens were _______________ eruptions |
ashfall |
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Mt. Pelee and Yellowstone are __________________ eruptions |
ash flow |
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What was unexpected and caused the most damage during the eruption of Mt. Saint Helens? |
lateral directed explosion |
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What is lahar? |
mudflow produced by hot volcanic ash melted snow |
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Yellowstone is/is not expected to erupt |
is |
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What has been the most expensive natural disaster? |
2011 Japan earthquake |
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What earthquakes resulted with a tsunami? |
2004 Indonesia
2011 Japan |
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Definition of an earthquake |
shaking of earth due to sudden release of stored energy in subsurface |
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why do we get earthquakes? |
movement along fault |
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What is the location directly above focus at Earth's surface? |
epicenter |
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What is the slowest seismic wave? |
surface wave |
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What wave causes the most damage? |
surface waves |
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What waves have vibrations parallel to wave movement? |
p waves |
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What waves have vibrations perpendicular to wave movement? |
s waves |
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What method is used to locate earthquake epicenters? |
earthquake triangulation |
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How are the numbers on the Richter scale determined? |
by the amplitude of spike on a seismogram |
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increase of one unit on Richter scale results in... |
10 fold increase in amount of ground movement |
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Four things that earthquake damage depends on |
earthquake magnitude
depth to focus
distance from epicenter
local geology |
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Five types of damage caused by earthquakes |
building collapse
liquefaction
fire
landslide
tsunami |
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What is it called when wet sand or clay turns to liquid during shaking? |
liquefaction |
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What will the strongest types of buildings be made of? |
steel frame |
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what will the weakest types of buildings be made of? |
adobe brick and mud |
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What are the similarities of the San Francisco and Kobe Japan earthquakes? |
Both had 7 magnitude
both had very high damage because it occurred in large urban areas and due to major liquefaction |
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What is the Big One? |
massive earthquake expected to occur within the next 30-100 years along San Andreas fault in California |
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What was wrong with Iben Browning's prediction? |
He used alignment of planets and moon to exert tidal pressure. There is no scientific basis for this method and no pattern between these things and earthquakes! |
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What are two clues for earthquake prediction? |
seismic gap and observation of precursor phenomena |
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What are some examples of precursor phenomena? |
small earthquakes
ground swelling and emission of radiowaves
animal behavior |
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Which two forms of earthquake predictions are sometimes successful? |
range of dates and short range predictions |
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What are four sources of evidence for continental drift? |
fit of continents
fossil evidence
distribution of paleoclimates
rock sequences |
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Who proposed continental drift? |
Alfred Wegener |
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Why was continental drift not accepted at the time? |
no reasonable mechanism
observations mostly from southern hemisphere, geologists hadn't seen them |
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What provides a mechanism for movement of continents? |
sea floor spreading |
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Ocean floor topography, earth magnetism, and paleomagnetism in rocks provide evidence for... |
sea floor spreading |
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What is sea floor spreading? |
when new ocean rock is created at oceanic ridge, moves laterally away, gets destroyed at trenches and sinks into mantle |
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What is the angle between magnetic force line and ground surface? |
inclination |
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What is it called when record of Earth's magnetic field is locked into a rock? |
paleomagnetism |
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Continents have/have not moved in geologic past
Magnetic poles have/have not moved |
have
have not |
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Earth's magnetic field has/has not reversed itself many times in geologic past |
has |
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What kind of magnetic field intensity has a positive magnetic anomaly? |
high |
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What explanation for magnetic anomalies is feasible? |
magnetic reversals |
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Why is this feasible? |
because the pattern of magnetic anomalies fits the pattern of magnetic reversals |
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The closer you get to an oceanic ridge, the older/younger the rocks are |
younger |
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What is the cold, brittle outer shell of earth that includes crust and upper part of mantle? |
lithosphere |
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What is the hotter, softer layer where rocks can flow over which tectonic plates move? |
asthenosphere |
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What occurs mainly at tectonic plate boundaries? |
geologic activity |
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Boundaries of tectonic plates are defined by ______________ locations |
earthquake |
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What is the defining feature of a divergent boundary? |
oceanic ridge |
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What kind of volcanoes occur at divergent boundaries? |
non explosive |
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Middle of Atlantic Ocean and Iceland are example of.... |
divergent boundaries |
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What are hot undersea geysers that produce jet stream of extremely hot water? |
black smoker |
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what are the two types of convergent boundaries? |
ocean/continent collision
continent/continent collision zone |
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Himalayas are an example of... |
continent-continent collision zone |
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Andes, Ring of Fire, and Cascades are an example of... |
ocean/continent collision |
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What is it called when denser ocean rocks subduct below continents? |
subduction zone |
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What occurs at transform boundary? |
lots of earthquakes |
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What is a localized zone of hot, upwelling mantle rock? |
hot spot |
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Things that plate tectonics explains |
earthquakes, volcanoes, mountain ranges
evidence for continental drift
evidence for sea-floor spreading
many other geologic data but NOT polar reversals, magnetic reversals, magnetic anomalies |
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What are some societal benefits of rivers? |
hydroelectricity, source of water, transportation, waste decomposition, ecosystem, fertile soil |
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what are some societal hazards of rivers? |
floods, erosion, invasive species, susceptible to pollution |
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What are rivers' importance to geology? |
sculpts landscape
deposits sediment |
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Why does river velocity increase going downstream? |
less friction on channel walls |
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What is the defining characteristic of mountain rivers? |
V-shape |
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What are the winding river paths of a meandering river? |
meanders |
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What happens in channel migration? |
Outer part of meander has high velocity, erosion occurs
Inner part of meander has low velocity, deposition occurs |
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What is an abandoned river meander? |
oxbow lake |
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What is an area drained by river and tributaries? |
drainage basin |
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What is a pattern of river and tributaries that often looks like veins of leaf? |
dendritic drainage pattern |
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What is the landform of deposited sediment at river mouth? |
delta |
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why has annual flood damage in USA increased? |
building more in flood prone areas |
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Why are average annual deaths in Europe and Asia from floods greater than those in USA? |
USA is wealthier so has better prevention measures, evacuation procedures, search and rescue |
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What type of flood is brief but severe due to a sudden rainstorm? |
upstream flood |
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What type of flood is due to prolonged rainfall and affects large areas for a long time? |
downstream floods |
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What is the biggest example of a downstream flood? |
Mississippi River flood of 1993 |
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In class, <1 flood per... |
12 rolls |
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4 methods of flood control |
preserve wetlands
channelization
dams
artificial levees |
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drawbacks of channelization |
sometime river returns to shape |
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drawbacks of dams |
sediment builds up and fills reservoir |
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drawbacks of artificial levees |
false sense of security
can fail catastrophically |
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4 solutions of reducing flood damage |
public education
mapping and zoning
mandatory insurance
relocation |
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top source of water on earth |
oceans |
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importance of groundwater (3) |
economic resource
waste disposal and polution
role in geologic hazards |
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ground water is located in... |
pore spaces |
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what is the measure of speed that water can flow through earth material? |
permeability |
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what measures how much water earth material can hold? |
porosity |
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what is an impermeable rock where water travels very slowly, can be porous but has low permeability? |
aquitard |
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saturated zone |
area with pore spaces completely filled with groundwater |
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unsaturated zone |
area with pore spaces filled with air |
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what is the boundary between saturated and unsaturated zone? |
water table |
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interaction of the water table with earth's surface |
rivers and lakes |
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is better to drill water well on hill or in valley? |
valley |
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speed of groundwater flow is related to the _________ of the water table and the _____________ |
slope
permeability |
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Two consequences of groundwater withdrawal |
lowered water table
ground subsidence |
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Superfund |
created with purpose of cleaning up worst of abandoned toxic waste |
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Examples of point sources |
factory discharge pipe
cemetery
landfill
gas station
animal feedlot |
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examples of non point sources |
oil spill
fields
cities |
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Movies involving groundwater pollution |
A Civil Action
Erin Brokovich |
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Boneyard Creek prevention measures |
channelization
retention ponds
not artificial levees |
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best solution for large waste sites |
layers of impermeable clay to isolate waste from aquifers |
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Importance of glaciers |
landscape development
effect on sea level
loss of inhabitable land
potential source of freshwater
avalanches
geology |
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If glaciers melt... |
sea level will rise |
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What two things do you need for glacier formation? |
cold temperatures and abundant precipitation |
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positive budget |
gains > losses, glacier advances |
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negative budget |
gains < losses, glacier retreats |
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In both situations, glacier continually moves... |
forward |
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During retreat... |
glacier covers less area |
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erosional features of glaciers |
striations and u-shaped valleys |
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three types of sediment deposits |
till, loess, outwash |
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Today the earth is in an _____________________ episode |
interglacial |
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What are scratches or grooves in bedrock caused by scraping of included rocks in moving glacier? |
striations |
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What sediments are deposited by water? |
outwash |
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What sediments are deposited by wind? |
loess |
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What sediments are deposited by ice? |
till |
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What are rocks that are dropped by ice? |
erratics |
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What is a moraine? |
hill of till |
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How fast do tectonic plates move? |
about 2-5 centimeters a year |
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Which plate boundaries produce mountain ranges? |
Convergent |
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Which plate boundary produces thickened continental crust? |
Continent-continent collision zone |
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With which kind of boundary is a black smoker usually associated? |
divergent boundary |
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What kind of geologic features are associated with hot spots? |
volcanoes |
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How does a hot spot produce volcanic rock of different ages at Hawaii? |
Pacific tectonic plate has moved over stationary hot spot, producing a chain of basalt volcanic islands in Hawaii |
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What is the longitudinal profile of a river? |
Characteristic downhill shape of a river along its flow direction |
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How is the longitudinal profile related to the size of sediment it carries? |
As river velocity increases downstream, they carry larger load and larger grains |
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Which is a better way to think about the risk of future flooding in an area? |
Think of the risk of flooding as a probability |
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How is flood recurrence determined? |
1/recurence x 100% |
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What is the location where water enters groundwater flow system? |
Recharge area |
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What is the location where groundwater leaves groundwater flow system? |
Discharge area |
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What is an aquifer that is overlain by a low permeability layer? |
confined aquifer |
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With high permeability, ______________ flow |
faster |
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With steeper gradient, _______________________ flow |
faster |
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In which parts of the world is groundwater a particularly important issue? |
Southwestern USA and many arid parts of the world where water is scarce because of low rainfall |
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What is a pleistocene time interval when continental glaciers repeatedly covered much larger part of Earth's surface? |
Ice Age |
