which volcano recently started erupting in the Philippines?
Mount Mayan
when is the Hypatia Stone hypothesized to have formed?
before our solar system formed
what do you call a scientific idea that has lots of support from being repeatedly tested?
a theory
what do you call an educated guess
a hypothesis
what explains that natural processes occur today the same way they did in the past?
uniformitarianism
what explains that six big bad-events formed the earth?
catastrophism
what explains the formation of our solar system?
the Nebular Hypothesis
what resulted from density stratification within the earth?
the Theia impact
how old is the earth?
4.5Ga
how does the Sun differ from a protostar?
protostars don’t have fusion occurring
what process formed the earth?
planetary accretion
how does continental crust differ from oceanic crust?
oceanic crust is denser
what are the five physical/mechanical layers of the earth?
- lithosphere
- asthenosphere
- mesosphere (lower mantle)
- outer core
- inner core
which layer of earth has the most ductile behavior?
outer core
define ductile
higher temperatures, solids start to become gooey
define brittle
lower temperatures, rock is strong and hard to break
why was continental drift initially rejected?
it couldn’t explain how plates moved
which discovery led to renewed interest in continental drift during the mid-20th century?
magnetic anomalies in seafloor rocks
what process helps tectonic plates move?
slab suction
what type of pate boundary experiences lots of underwater volcanic eruptions?
a seafloor spreading site
what is a subduction zone?
the plate with oceanic crust is forced down
where can a modern collision zone boundary be found?
the Himalayas
what forms where two plates of continental crust collide?
mountains
what is the most abundant element in earth’s crust?
oxygen
what are five criteria for minerals?
- naturally occurring (non-synthetic)
- inorganic
- crystalline (not amorphous)
- solid
- set chemical composition
how are minerals classified?
minerals are grouped by a common anion
what is sulfate used for?
used to make plaster
where are phosphates found?
found in bones & teeth and fertilizer
where are carbonates found?
the shells of most seashells, living organisms
what is the most common mineral group?
silicates
what is the structure of silicates?
tetrahedron
what kind of rock would melt at the lowest temperature?
a wet rock under low pressure
what are the three types of magma?
- basaltic magma
- andesitic magma
- rhyolitic magma
what is the SiO2 content and melting point of basaltic magma?
50% SiO2 content
>1100 degrees Celsius melting point
what is the SiO2 content and melting point of andesitic magma?
60% SiO2 content
1000-900 degrees Celsius melting point
what is the SiO2 content and melting point of rhyolitic magma?
70% SiO2 content
800-700 degrees Celsius melting point
define partial melting
some minerals melt while others remain solid
define equilibrium crystallization partial freezing
no change in chemical when freezing
define fractional crystallization partial freezing
(more common) some fraction gets pulled out while its freezing
which mineral is associated with the continuous branch of Bowen’s reaction series?
plagioclase
what kind of texture is associated with extrusive igneous rocks?
glassy
what are the two types of igneous rock?
- plutonic (intrusive)
2. volcanic (extrusive)
what are the textures of intrusive rock?
- pegmatitic
2. phaneritic
what are the textures of extrusive rock?
- porphyritic
- aphanitic
- glassy
- vesicular
which igneous rock composition has the highest silica content?
felsic
what is viscosity mainly controlled by?
temperature and silica content
recently erupted lava with a stringy, ropey appearance is called what?
pahoehoe
what are four types of plutonic rock?
- dikes
- sills
- laccolith
- batholith
what super volcanic eruption caused “the year without a summer”?
tambora
shield volcanoes typically have what type of eruptions?
non-explosive
what area recently experienced a magnitude 6.4 earthquake?
Taiwan
what was the result of a comet hypothesized to have struck the earth 12.8ka?
a 1,000 year cold period
what refers to the breakdown of rocks?
weathering
what refers to the transport of sediment?
erosion
what allows feldspar to chemically weather into kaolinite?
H2CO3 and water
what refers to the lowering of ground level?
subsidence
what factors can make a slope unstable?
- too much water present
- too little water present
- the slope exceeds the angle of repose
what can be done to stabilize a slope?
install drainage devices
what type of metamorphism would be the result of a formation of a laccolith?
contact metamorphism
what is fault metamorphism?
metamorphism via fluids
what is metasomatism
when rocks interact with heated up ground fluids
what metamorphic rock would form as a result of differential pressure?
gneiss
what refers to how much the parent rock was altered?
grade
what refers to a set of index minerals?
facies
what metamorphic facies is associated with low grade metamorphism?
xeolite
what refers to the temperature change with increasing depth below the surface?
geothermal gradient
what facies is associated with contact metamorphism?
hornfels
what are the three types of tectonic forces?
- tensional force
- compressional force
- shearing force
what forms as a ductile response to compressional force?
a fold
what fault forms as a result of tensional force?
a normal fault
what fault forms as a result of compressional force?
a reverse fault
what fault forms as a result of shearing force?
a left lateral fault
is the Grand Canyon a geologic structure?
no
how many magnitude 2 earthquakes occur on earth each year?
1 million
what refers to the point directly along the fault where movement occurs during an earthquake?
the focus
what are associated with earthquakes with unusually deep foci?
subduction zones
what seismic waves are shear motion?
S-waves
what seismic waves are compressional?
P-waves
what material is safest to build on in areas prone to earthquakes?
bedrock
what scale do scientists use to measure earthquakes?
moment
what factors would cause an unconformity to form?
- the sediment supply ran out
- there was no accommodation space
- erosion occurred faster than deposition
what type of unconformity could be present between layers of sandstone and shale?
disconformity
what geologic principle tells you that a dike is younger than the strata the magma moved through?
cross cutting
what geologic principle is best for correlation?
faunal succession
what correlation method utilizes unconformities?
sequence stratigraphy
dinosaurs lived during which geologic eon?
phanerozoic
what absolute dating method does not rely on radioactive isotopes?
dendrochronology
how long is one half-life?
the time needed for half the parent atoms present to decay
what is needed in order to conduct radiometric dating?
- radioactive isotopes must be present
- need measurable amounts of parent and daughter isotopes
- must be a closed system
if a specimen was an open system and parent atoms were leached out, what will happen when you date that specimen?
the age you calculate will be too old
what can you date with C-14?
any kind of biologic material
C-14 can date specimens as old as…
57,000 years old
accommodation space measures the space available for what?
sediment deposition in a basin
what did a recent study suggest cooling 2.7Ma was caused by?
dust blown into the Pacific
what feature did a recent study of volcanic eruptions focus on?
dikes
climate reflects surface conditions on earth over what timescale?
decadal
which Milankovitch cycle describes the wobble of earth on its axis?
precession
what is the duration of obliquity?
41k years
what is a measure of reflectivity?
albedo
greenhouse gasses compose about how much of the atmosphere?
less than 1%
what cells transport heat from the equator to about 30 degrees latitude?
hadley cells
what happens to upwelling in the eastern pacific during an El Niño event?
upwelling stops
why does El Niño cause weather changes in South Carolina?
the Jet Stream gets displaced
why is thermohaline circulation slowing down?
the North Atlantic is getting warmer
what ratio has fossil fuel burning altered in the atmosphere?
14C/12C
why is a 3 degree global average temperature increase considered problematic?
many species would likely go extinct
what refers to things made or caused by humans?
anthropogenic
what refers to removing only fine grained material from the surface of a desert?
deflation
what explains the unusually fast movement of some glaciers?
basal slip
what type of lake is associated with glacial erosion?
tarns
what do outwash sediments compose?
eskers
at what rate is San Francisco sinking?
1 cm/yr
what problems can result from overdrafting?
- subsidence
- cones of depression
- saltwater contamination
what are the small stream branches near the mouth of the river?
distributaries
what rivers have been the cause of lawsuits between states regarding water availability?
- catawba
- tennessee
- colorado
fossil fuels provide what percentage of our domestic energy needs?
81%
what is nuclear waste with a half-life of > 20 years?
trans-uranic
what must an area be classified as to be a candidate for generating wind power?
class 3 or higher