Geology Test 4 Flashcards

Terms Definitions
Always white
Marble, quartzite, anthracite
Harry Hess
"Sea-Floor Spreading"
2005 Pakistan Earthquake
interiors of the continents
Channel Types
Straight, meandering, braided
between Felsic and Mafic
_________is an intermediate rock.
It is made up of plagioclase feldspar and mafic minerals. It is usually grayish or greenish in color.
minerals precipitate around deposited particles and bind them together.
all carnivorous dinosaurs are classified as
batteries, gasoline additive, solders, seals, TV tubes, TV glass, ceramics, protective coatings
solid @ earth temp
mineral characteristic
tsunami may move at _________kilometers per hour
Dessication cracks are common features:
(a) near coastlines
(b) in arid regions where the groundwater table drops
(c) in high elevations
(d) in areas where igneous rocks are common
Meander Cutoff
creates the oxbow lake
bioclastic sediment
a shallow-water sediment consisting primarily of two calcium-carbonate minerals
Effusive Eruptions
Non-explosive, produce mainly lava flows. Favored by low gas content and low viscosity (basaltic to andesitic magmas). Fountaining can occur
Composite Volcano
lava flows and pyroclastic debris
tall, wide
intermittenly erupts
felsic lava
dissolved gases in it
More static stress
The more ductile behavior.
hot spring
heated groundwater rises to surface
Body Wave
Both Primary and Secondary waves.
In Southern California, great earthquakes occur on the San Andreas approximately every ________years.
150-300 years.
Fissure Eruption
Fractures leaking lava or pyroclastics, may be large or small basaltic or rhyolitic
diagenesis would most be associated with which rock group?
Mollusk has right and left shell.
Stratified drift
-Transport of Sediment by Glaciers-Deposited by meltwater flowing from ice rather than by ice itself
fracture zones
occur perpendicular to midocean ridges; narrow bands of vertical fractures
Well-tested and widely accepted view that the scientific community agrees best explains certain observable facts.After a Hypothesis has faced scrutiny and competing models have been eliminated it then is a Theory
What is an anion?
- charged ion
in polar regions, lower layer frozen year round, upper layer thaws and slides downhill slowly
The mechanical transfer of heat energy (the vibrational energy of thermally agitated atoms and molecules by the mechanism of atomic or molecular impact).
the layer closest to Earth, where almost all weather occurs; the thinnest layer
High Winds
A steep pressure gradient indicates ________.
Hydrologic cycle
continuos interchange of water among ocean, atmosphere, and continents. Powered by sun
alluvial fans
fan-shaped desposit formed where a fast flowing stream flattens, slows, and spread typically at the exit of a canyon onto a flatter plain
chemical sedimentary rock
sedimentary rock consisting of material that was precipitated from water by either inorganic or organic means
atomic number of an element is determined by the number of
core of earth
liquid iron- outter
solid iron- inner
passive margins
have no active tectonics-- continental shelf, has gentle slope
no volcanoes or earthquakes
Sudden loss of strength of water saturated soils during an earthquake. *Remember buildings that just fell over.
inrusive (plutonic
igneous rocks wherein the magma crystallizes at depth in the earth
Soil profile
the vertical succession of soil horizons
Shield Volcano
type of volcano, passive erruptions, made of lava flows, huge structure with massive width to height ratio
First fossil of land plants Silurian age. Simple dividing branches. Spores at branch ends.
Easily Fossilized
Soft-bodied animals are almost never fossilized. Shells, teeth and bones are often fossilized.
a concrete or stone wall built perpendicular to a shore line in order to prevent beach drift from removing sand
very large cave or system of interconnected cave chambers 
-Carlsbad, New Mexico=one chamber 1200 m long, 190 m wide, 100 m high
(formed from surface acid)
-Mammoth Cave, Kentucky=consists of interconnected caverns w/ aggregate length 48 km
continental slope
-the boundary between the continents and the deep ocean basins lies along the continental slope, which is a steep dropof that extends from teh outer edge of the continental shelf to the floor of the deep ocean
-using this as the dividing line, we find that about 60% of eath's surface is represented by ocean basins and the remaining 40% by continents
Magnetic orientation in rocks that is opposite to the current orientation of Earth's magnetic field is called _______ magentic polarity
brittle deformation
rock fractures after elastic limit surpassed
When was the Paleozoic Era?
542MYA to 251MYA
the volume of open space between earth materials
Cretaceous/Western Interior Seaway
Larger version of Sundance Sea. Shallow,warm equatorial regions full of life
. Fig. 1 illustrates the surface currents of the global ocean. Which of these currents was named after a famous naturalist, i.e., a scientist (biologist-geologist) who discovered new volcanoes and hundreds of new species?
Humboldt current
inner core
earths magnetic field results from the spinning of the _____ ____.
plutons are
igneous bodies that formed from magma that cooled and crystallized within the Earth's crust
What metamorphic rocks are classified primarily according to
foliated or non-foliated
small, cone shaped hills formed at the glacial front by meltwater pouring sediment off the glaciers surface
narrow hill of resistant rock with a flat top and very steep sides
principle of superposition
Nicolaus Stenos principle that states in an undisturbed sequence of strata, the oldest strata lies at the bottom.
lateral movement
when plates move back and forth parallel to each other
"Intrusive igneous rocks crystallize to a solid- where as extrusive igneous rocks crystallize to a solid_"
/underground, at the surface.
Bowen's reaction series
predicts the order of crytallization "dis/continuous"
Angular Unconformity
An unconformity where the older strata dip at an angle that is different than the younger strata
Brittle Material
Rock breaks quickly into sharp pieces. Faults can develop. Break in shallow depths of faults
constructive forces
Forces that shape Earth's surface by building up mountains and landmasses
flood warning
flood is actually occurring or is imminent.
Stable isotopes
are those that don't change over time
Which of the following minerals does not have cleavage? A. halite B. feldspar C. quartz
C.    quartz
An arched shaped fold in which the rock layers dip away from the fold axis; important in oil production (think the downward slopes on the sides of a hill. Result of compressional forces
rock flour
when rocks in bottom of glacier produce pulverized rock / rock powder-->can cause glacier to appear gray / milky{PRODUCED BY GLACIAL ABRASION - friction}
urban air pollution
air pollutants are airborne particles and gases that occur in concentrations that endanger the health of organisms and disrupt the orderly functioning environment
define epicenter
the point on Earth's surface directly above the focus of an earthquake
Active continental margin
The thick continental crust meets the thin oceanic crust at a subduction zone.
the name of the island series not covered by the Sauk Sea
Transcontinental Arch
sediment in part of a valley that is inundated during a flood
Foliated Texture
Set of wavy or flat parallel planes produced by deformation under directed pressure
Oxbow Lake
a curved lake produced when a stream cuts off a meander; the flow of water is cut off when the meander is formed thus forming a lake
Head(headwaters) of a stream
The beginning point of a stream.
The crust underneath mountains is -- whereas the lithospheric mantle thickness is --- with respect to immediatley adjacent regions.
Thicker, the same
of all the geological commodities used by the people, which on is the largest?
sand, stone, gravel
antecedent stream
A stream that continued to downcut and maintain its original course as an area along its course was uplifted by faulting or folding.
a river or sheey of ice that slowly flows across the land surface and lasts all year long
Which of the following would be considered a point source of pollution?
Industrial wastewater discharge
Gases held in the magma. As the near the surface the pressure lessens and the gases inside expand causing violence.
Factors that determine violence/explosiveness of Volcanic Eruption
The viscosity determines the violence which is determined by:1)Composition of Magma2)Temperature of Magma3)Dissolved Gasses in MagmaMore Visous = More Explosive
What makes a good aquifer?
o High porosity (for water storage)
 Porosity: total amount of pore space
o High permeability (for water transmission)
Sedimentary rocks are considered
THe rock is composed almost entirely of fossil fragments
What are slower seismic waves
-hot rocks
-beneath volcanic areas and mid-ocean spreading ridges-Hawaii
Testing of moon rock samples aged earth at
4.6 billion years old
Angle of Inclination
23.5 degrees; rotation on axis in 24 hrs; point on equator moves at a thousand miles per hour; North Pole moves at zero miles per hour
What are two most common elements in the earth's crust?
oxygen and silica
-quickly decreasing pressures
-increasing temperatures
-adding water
In the mantle, magma can start to form, aided by which of the following conditions?
1.) What are natural triggers of mass wasting.
2.) What are human triggers?
1.) Heavy Rains
Oversteepened Slopes
2.)Removal of vegetation
Kettles result from
Melting of large ice blocks. They are a depression
what are the parts of a wave
Wave length, Crest and Trough
intensity and duration of rainfall, prior wetting condition of the soil, soil texture, slope of the land, nature of the vegetative cover
5 factors that influence infiltration capacity
the reason diamond and graphite are distinct minerals is that
they have different atomic structures
Right Lateral Fault
The plate on the right moves down and the plate on the left moves up
what is a tephra fall
rain of devris particles as eruption cloud drifts w/ upper winds
How fast does ground water flow
few meters per year.
15 centimeters a day
List/Define 3 types of boundaries that occur where tectonic plates meet
Transform- plates sliding past each other/miss
Divergent- Divide/parts moving away
Convergent- Collide
could the impact have been minimized in tsunami at sumatra in 2004
because seismic waves travel faster than tsunamis, rapidanalysis of seismograms can identify earthquakes likely to cause major tsunamis and predict when waves will arrive. also, deep ocean buoys can verify tsunami
What is a convergent boundary?
2 plates collide & 1 goes under or merges with it
Regions of U.S. where most tornadoes occur;
The highest risk for tornadoes occurs along what is called "Tornado Alley", a belt that stretches from north to south through the central United States.
What are the three main steps that lead to glacial formation?
Snow falls - accumulates, Compaction, Recrystallizes
detrital uraninite and pyrite and the composition of the early atmosphere
Further evidence of the lack of oxygen in the early atmosphere is provided by detrital uraninite and pyrite and by paleosols—i.e., fossil soils. Detrital uraninite and pyrite are readily oxidized in the presence of oxygen and thus do not survive weathering processes.
Why do composite volcanoes consist of alternating lava and pyroclastic layers?
The lava flows then the ash falls on top of that layer and then is covered by more lave and so on
glaciated valleys
slab pull
cross sectional view
key beds
layered rocks/unique
Prarie Potholes
small marsh-like ponds
the study of earthquakes
lands that flood periodically
record created by seismometer
A feldspar mineral (K, Al)
Brittle Strain
(fracture) rocks are faulted
a felsic, coarse-grained, intrusive igneous rock composed of quartz, orthoclase feldspar, sodium-rich plagioclase feldspar, and micas. intrusive equivalent of rhyolite.
natural gas
120-225 Celsius
4-7 km depth
reverse fault
hanging wall moves up
used to calculate hydraulic conductivity
When did reptiles originate?
late pennsylvanian
What are cinders?
pea-sized pyroclastic material
Mechanical weathering
(physical weathering) reduces solid rock to small fragments but does not alter the chemical composition of rocks and minerals
instrument that detects and records earthquake waves
anticlines and synclines. Most folds are the result of horizontal compressional stresses
By definition, stocks differ from batholiths in
process where one building repeatexly banges into another in an earthquake
saltation bed load
intermittently bouncing and skipping
the average conditions of Earth's surface environment and their variation
flatter particles settle slower then rounder ones
-lifting and carrying of rocks
-glacial erosion
rocks 2
properties of minerals are changed
outermost reaches of the solar system
lost an electron, gains positive charge
Influence on Mass Wasting:

Triggering Mechanisms
Excessive Rainfall
Naturally occurring
True minerals form by geological processes
steep bluff adjacent to and adjoining a beach or coastal environment. caused by erosion, landslides, weather, and runoff of surface water
Collision Boundaries
Usually start off as subduction boundaries. Earthquakes here occur because of thrust faulting and are shallow-focus
a tentative explanation that is then tested to determine if it is valid
Tectonic Creep
Gradual displacement that is not accompanied by felt earthquakes
as compared to coarse grained igneous rocks all fine grained igneous rocks cool and solidify more
Chemical Sedimentary Rocks
Rocks produced by chemical precipitation of minerals from solution.
Rock Salt
Rock Gypsum
an impermeable bed that hinders or prevents groundwater movement
agents of regional metamorphism
temp and direct pressure
topographic map
shows the shape of the land
what is the mean depth of sea
All water on and in Earth
(oceans, glaciers, lakes, groundwater, and rivers)
JD Rockefeller made his early fortune selling?
a sandstone subtype composed of at least 25% angular to subangular sand-sized particles of feldspar
Types of faults
Normal, Reverse, Thrust, and dip-slip
always younger than the rock layers around and beneath it
daughter isotope
The decay product of radioactive decay) is known
the physical removal of material by mobile agents such as water, wind or ice
referring to metamorphic rocks, ______ is the rock type that was metamorphosed
parent rock
earth's four layers -
lithosphere, asthenosphere, inner core, outer core.
parent rock composition
new metamorphic rocks have similiar composition to parent rock
Explosion of Life - life in sea reaches land, max extinctions (trilobites)
outer core, inner core
the earth's __________________ rotates faster than the earth's ______________ .
cavity or solution
type of porosity found in limestone
A depression in the shape of the object
sea floor spreading
how is new ocean floor formed
greenhouse effect
radiant energy that is absorbed heats earth and eventually is reradiated skyward
Three Eons
Archean- 4.5 to 4.8 bya
Proterozoic - 2.5 bya to 545 million
Phanerozoic - 545 mil to present
what are the 4 factors that determine whether a rock will exhibit brittle or ductile behavior?
What region in Earth consists primarily of olivine and pyroxene?
The upper mantle.
geothermal gradient
rate of change in temperature with depth
the capacity of a rock to transmit fluid
through pores and fractures
the vertical drop (slope) of a stream channel over a distance is called?
pyroclastic features
volcanoes throw fire like material, or bits of earth
a bar of magnetic material (as soft iron) that passes through a coil and serves to increase the inductance of the coil
Goal of any psychologist
To understand and predict behavior.
The causes and effects of glacial and interglacial periods can be seen as a correlation between geological, oceanic, and _______ evidence
A well tested and widely accepted view that the scientific community agrees best explains certain observable facts
Describe shear.
stress that causes two adjacent parts of a pudy to slid past one another
basal slip
Entire ice mass slipping along the ground
Most glaciers are thought to move this way by this process
What is longshore transport?
Method by which dynamic coastline features, such as beaches, spits, dunes, and offshore bars are built and maintained
angle of repose
the steepest angle at which loose material remains stationary without sliding downslope
shaped that way because of an uneven slope
pistol-butt tree
Mercalli scale
The scale of earthquake size based on reports of damage done by earthquake
any member of a group of mammals that included the ancestors of both marsupial and placental mammals
figure 1.11
ridge away from land, trench next to land
metal resources are:
copper & iron, aluminum, gold, and silver
A hot or cold mixture of water and rock fragments flowing down the slopes of a volcano or in a river valley.
groundwater depletion
in most places the recharge of water to the aquifer is less than the amount withdrawn
Transgression of Zuni Sea
LATE JURASSIC peak transgression, sea extends across western north america
________ is a complex misture of hydrogen and carbon compounds
unrefined liquid phase is called ________
vapor phase is called _________
Crude Oil
Natural Gas
Streamlined hills are usually formed because of....
drumlins (and therefore, glaciers)
3 types of delta beds
1)FORESET BEDS-coarser particles drop out immediately form layers sloping down2)TOPSET BEDS-usually covers foreset bed-deposited during flood stage3)BOTTOMSET BEDS-finer silts and clays settling out at a distance from mouth-horizontal layers
Primary Wave
Fastest type of wave produced by EQ. Energy moves parallel to the wave motion. Can pass through solids, liquids, and gases
solar nebula
A disk of gas and dust that surrounded the Sun during the formation of the early solar system. Once formed, the disk began to cool, and many of the gases condensed. Gravitational attraction caused the dust and condensing material to clump together into planetesimals, the Moon-sized bodies, and finally planets.
a nonfoliated texture does not exhibit
any discernible preferred orientation of the mineral grains
Sedimentary Rock
Rock that forms at or near the surface of the Earth by the precipitation of minerals from water solutions, by the cementing together of shell fragments, or of loose grains derived from preexisting rock
the flux that removes excess calcium from the ocean basins is
sedimentation of calcium carbonate
About 63 %
About how much of the needed oil supply (in %) are the United States importing
Secondary Waves are ____ waves that travel like a....
body waves; waving rope
Name the three families of rocks?
Sedimentary, metamorphic and igneous. (Hydrothermal rocks are formed from precipitation of hot water)
P wave shadow zone
between 105 and 142 degrees because p waves are refracted at the core.
Extrusive rocks rate of cooling
fast rate of cooling (many small crystals)
like jetties but purpose is to save the beaches is a
groin or groin field
clastic sedimentary rocks
are classified by grain size & form in tectonic basins
Only shallow earthquakes occur at midocean ridges because
the lithosphere is thin and earthquakes cannot occur in the ductile asthenosphere.
Factors that control how rocks deform
1. Rock type
2. Confining and directed pressure
3. Temperature
4. Rate of deformation
5. Time
6. Fluids
Transform faults are associated with
strike slip on a ridge. San Andreas Fault
Our solar system: planet composition
varied w/ distance from Sun
• Inner planets: small; rx + metals; volatile
materials not retained in quantity
• Giant outer planets: volatiles swept
pushed to cold outer solar system to form
giant planets (ices + gases surrounding
rocky cores)
The fossils of multicellular life forms observed in rocks:
can be used to correlate the rock layers.
What effect do CO2 levels in the atmosphere have on climate and chemical weathering rates?
increase temperature and therefor rate of chemical weathering
When mixed with water, produce increased amounts of carbonic acid
What is the law of superposition?
The layer of rock on the bottom is oldest, while the layer that gets higher and higher gets younger. The top is the youngest.
Describe the ULVZ zone at the core-mantle boundary
may be due to hot core partially melting overlying mantle rock or to part of the liquid outer core reacting chemically with the adjacent mantle.
How does geologic time enable us to use ordinary, observable processes to explain most of what we see on earth? (uniformitarianism)
Over such long periods of time, many seemingly insignificant natural processes can produce major results. Therefore,most of the earth's geological features can be explained in terms of ordinary, observable processes acting over geologic time spans.
charged particles
small channels
concentration by weathering
most common mineral
P waves
Primary waves
compressional waves
waves expand and contract
travel 6-7 km/s
similar to the motion of sound waves
jawless armored fish are
i love you monica
bony skeleton
nervous system- brain, sensory structures
Compostional Zoning
inclusion of other materials
Rocks coming to the surface
a concave-shaped volcano containing alternating layers of lava flows and beds of pyroclasts.
0.75 km
average height of land
conical hill statisfied drift orginally deposited depression
baseflow recession
decrease in stream flow
Hard stabilization
working against beach processes-–Groins, jetties, breakwaters, seawalls.
What influences drainage basin?
Slope, Shape
clastic (detritatl)
Pieces of preexisting rocks (shale,sandstone) formed along stream beds, bases of mountains, deep ocean
Aa flows
rough, jagged blocks. Basaltic lava
the name of the super continent
metamorfic rock
a rock produced by metamorphism
Divergent boundaries
Where does decompression melting occur?
an abundant carbonate rock composed primarily of dolomite and formed by the diagenesis of carbonate sediment and limestones
Strike-slip faults exhibit what kind of movement?
Metamorphic rocks
Rocks changed by temperatures, pressures of deformation
Paleozoic marine arthropods of the class of Crustacea, characterized by longitudinal and transverse division of the carapace into three parts, or lobes. Trilobites were especially abundant during the erarly Paleozoic
transform faults
experiences strike - slip motion
at their two ends they transform into some other type of plate tectonic boundary
oxygen revolution steps
photochemical dissociation and photosynthesis
Tectonic Cycle
-Motion of earth's fragmented

-Lithosphere over asthenosphere

-Divergent and Convergent Plate Boundaries
Pressure gradient
Earth's center / probably 3,600,000 atm (atmospheric pressure = atm)
Also increases as you get deeper (with depth) more pressure
Pressure holds those minerals together to maintain a solid
S waves
_______ do not travel through liquid.
Travel with a velocity that depends only on the rigidity and density of the material they travel through; shear body waves. Arrive later than P-Waves
liquid portion composed of mobile ions of those elements commonly found in the earth's crust
Richter scale
Earthquake scale based on energy released
as compare to ultramafic rocks, mafic rocks have greater/lesser proportion of silica
a contour that connects points of equal age on the world's ocean floors as determined by magnetic reversal data and fossils from deep-sea drilling.
The hypothesis that explains the formation of the solar system is referred to as
nebular hypothesis
which type of sedimentary rock is classified by dominant mineral?
one of the small inner rocky planets
Characteristics of wide valleys
Stream near base level
Meanders, cutoffs, oxbow lakes
The person most responsible for determining the properties of radiation/half life?
Madame Curie
Point where the energy is first converted into a seismic wave
Coral reefs
Created from secretions of organisms, Warm clear water of pacific and Indian oceans
Laurentia consisted mostly of
North America and Greenland
berm crest
divides the beach face and berm.
movement of rocks in streambed by rolling, sliding, dragging.
Infiltration is affected by
-Ground Slope-Soil Type-Rainfall Intensity-Soil Saturation-Vegetation/Land Use
Wegner's continental drift
Fit of the continents
Rock type & structural similarities
Paleoclimatic evidence
accretion occurs in ________
dust and ice rings
pillow basalts
magma extruded under water and rocks were uplifted and exposes
base level
Lowest elevation to which the stream can erode downward, for many streams, the water surface level of the body of water into which they flow
a hornfels rock is formed by _______ metamorphism.
What metals is commonly mined as an oxide?
Environment of deposition
The location in which deposition occurs. Typically deep sea floor, beach, desert dunes, river channel, or lake bottom.
East African Rift is what kind of boundary/
what are the rings of Saturn made of?
If the position between antennas on two plates moving away from each other changes by 5mm/yr, then each plate is moving at approximately_________.
2.5 mm/yr.
igneous lava that cooled into a crack cutting through another rock
Capillary Fringe
the top part of the groundwater profile which small vertical threads of water go up above the water table is called what
a type of chemical bond that shares electrons is called?
cambrian- regression or transgression?
i. seas coming in (transgression)
What effect does gravity have on horizontal air motion?
No effect
Primary Treatment
with respect to a wastewater treatment plant, includes screening and removal of grit and sedimentation of larger particles from the waste system.
The seaward movement of the ocean defines a. uniformitarianism. c. regression.b. transgression. d. Wilson cycle.
c.    regression.
extends from the surface to the center of the planet
describes how steeply the bed is dipping
dip angle
glacial drift
refers to all sediments of glacial origin
how are earthquakes predicted over the long term?
using historical records
Bay of Fundy
what bay has the greatest tidal range?
transition metals
those elements found in the middle of the periodic table
same types of some Mesozoic animals are found as fossils in areas that are
now widely separated
Divergent Boundary
A boundary at which two plates move apart from one another
ocean basins
7/10 of the earth's surface-- only 5 miles thick
What is an Isotope?
variants of the number of neutrons
the process in which one type of rock changes into metamorphic rock because of chemical processes or changes in temperature and pressure
Safety Factor
Ratio of the resisting force to the driving force, evaluates slope stability
A mineral family that makes up 90% of the earth's crust (SiO2).

One of two or more forms of an element that have the same atomic number but different atomic masses.
Seismic refraction
bending of seismic waves as they pass from one material to another having different seismic wave velocities
sand enrichment
bring in sand from other areas to fill in beach
what are the magnetic poles?
-poles (2)
N and S poles
exotic streams
streams that have water in them all of the time
WHat are mine tailings
waste rock dug out of a mine
Metamorphic rock
form by the change of one rock to another by temperatures and pressures. They can be formed by any type of rock. They can NOT be formed on the surface, they must be buried. and the rock must ALWAYS stay solid. new minerals are formed without changing the chemical composition.
topographic maps
a map that shows the shape of the land; closely spaced lines show a steep slope, Circular lines show a hill or mountain, widely spaced lines show gentle slope.
a lake that is formed by 2 outside loops eroding away until they hit each other and break is a
oxbow lake
the suggested age of our solar system
13.7 billion years old
Archean Era (3850 mya-2500 mya)(4)
-first sedimentary rocks (beginning of water/atmosphere induced weathering)-first microfossils appear 3500 mya-Don't really know early life origins, but assume that there were cyanobacteria that had oxygen as waste products-stromalites grow in mats of cyanobacteria that trap fine sediments; produce atmoosphere while the fossilize
In which stage do the core and mantle form?
Accretion and Differentiation
Significance of weathering and Erosion
1. shapes the earths surface
2. forms soil
3. formation of some ore deposits
4. affects the carbon dioxide cycle
influences of parent material
the rate of weathering, their rate of soil formation and the development on unconsolidated soil
How much garbage does NYC produce in a year?
4.4 million tons
the greatest expanse of time Ex.: Precambrian & Phanerozoic
the various forms of fish have included
jawless and jawed armored formed, cartilaginous forms, and bony forms
Many hill-slope masses are weak due to preexisting geologic conditions such as __.
All of these are correct
what 2 conditions are generally necessary for a fossil to be preserved in the geologic record?
posession of hard parts and rapid burial
Techniques of analyzing the Earth's climate history
Looking at the sea floor sediment, and oxygen isotopes are used in analyzing what?
• What is the evidence that the Archean ocean and atmosphere were really different in composition (low in oxygen) from what we have now (high in oxygen)?
• Differences between archean an modern subdutCion
o More convection cells, foster convection
o Only very small pieces of continental crust
o Composition of continental crust is different
o Modern: melting mantle by adding h20
o Archean: melting of slab itself
• Difference between archean and modern ocean
o Archean: fe2+ and Si rich
o Fe2+ : weathering from rocks, staying dissolved until bacteria oxidized it
o Low energy: had to be to keep Fe as Fe2+
o Atmosphere had no free oxygen but had methane, ammonia, and water
• Earth was 3-2x hotter in archean
o Vigorous mantle convection
o Lots of tiny plates and volcanism
o Little clastic sediment
out of all energy we use, ___% comes from renewable resources
7% (eventually we will run out)
What happened during the 1886 earthquake?
It was a major earthquake over 7 in magnitude that severely damaged Charleston.
How does geologic time enable us to use ordinary, observable processes to explain most of what we see on earth? (uniformitarianism)
Over such long periods of time, many seemingly insignificant natural processes can produce major results. Therefore,most of the earth's geological features can be explained in terms of ordinary, observable processes acting over geologic time spans.
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