SCREW DWORKIN FOR THIS Flashcards
Bing Bang Theory
13.75 billion years - origin of the universe
Why do scientists think the world is expanding?
Red shift - Doppler effect. Everything in the universe is moving away from everything else.
First material to form
Hydrogen and helium
Where did other elements come from?
Heavier element are formed in stars, process of fusion
Origin of our solar system
Rotating nebula
Energy Sources
Impact energy (meterorite), Gravitational energy, Radioactive decay, Sun
Radioactive Emmissions
Alpha particles, Beta particles, Gamma rays
Internal Sources
Earthquakes and volcanoes - radioactive materials
External Sources
Weather - Sun
Mineral
Naturally occuring inorganic solid, can be expressed by chemical formula
Chrystelline
Orderly and repetitive atomic arrangement
Diamond
South Africa is the largest producer, they form at high pressures and temperatures deep within the earth, hardness of 10
Kimberlite Pipes
Deep explosive volcano
Corundum
Ruby - red, Sapphire - blue, hardness of 9
Turquoise
Found in volcanic rocks, softer, hardness of 6
Quartz
Amethyst, many different varieties - usually in color
Basaltic
50% SiO2, flows easily
Granitic
60-70% SiO2. Viscous - does not flow easily.
The Great Molasses Flood of 1919
Boston - 21 people died and 150 injured. Rescue workers got stuck in the viscous mess
Texture
Size of the crystals, Igenous rock textures
Glassy
No distinct grains, rapid cooling
Aphantic
Fine grained, extrusive, quick cooling
Phaneritic
Course grained, intrusive, magma cooled slowy, igneous rock composition - need to know
Coarse
Granite, felsic (light color), diorite, intermediate
Gabbro
Mafic (dark color), Fine
Rhyolite
Felsic (light color)
Andesite
Intermediate
mafic
(dark color), the origin of magma, originates 30 to 120 miles bewlo the earth;s surface, geometry of intrusive igneous rock bodies
Batholith
Huge mass of coarsely crystalline igneous rocks
Stock
Small Batholith
MSH Aftermath
57 people died, only 3 of the 57 were in restricted zones
Lahar
Volcanic mud flow
Lava dome
lava which is forced from the vent much like toothpaste from a tube, forming a half-ball shape over the vent.
Harry Truman
Mt. St. Helens Lodge owner on spirit lake, didn’t leave the mountain
Sediment
Material that has been transported by a current, 75% of continents are covered by sedimentary rocks
Detridal
Made up of broken particles of pre-existing rocks and minerals. Megascopic pieces.
Chemical
Precipitated from solution. Dissolved elements form together to make a sedimentary rock. Atoms bond and travel.
Sediment Sizes
Gravel, Sand, Silt, Clay
Conglomerate
Composed of gravel. Rounded clasts. Very high energy environment.
Sandstone
Composed of sand sized sediment (2mm to 0.62) Beaches.
Siltstone
Composed of silt sized (0.062 to 0.0004 mm) sediment. Low energy.
Shale
Composed of clay sized sediment. Very low energy environment. Has organic matter and oil in shales.
Limestone
505 calcites. Formed in marine environments. Composed of dead marine organisms. Aquatic animals and plants precipitate calcite.
Halite
Salt
Rock Beds
Layers of sedimentary rock, stratified. Most common feature.
Ripple Marks
Small linear ridges of sediment. Forms when a current moves over sediment.
Cross Beds
Inclined layers within beds. (Zion) Cross beds form as ripples or dunes migrate.
Sedimentary rocks have porosity
Empty space that can be occupied by a fluid. Fluids that make money are water and oil.
Metamorphic Rocks
Rocks that have formed in the solid state in response to changes in temperature and pressure. Parent rock recrystallizes (changes the shape and orientation of crystals), classification of rocks are based on presence or absence of foliation.
Foliation
Planar feature, caused by parallel alignment of platy minerals or banding.
Slate
Fine grained, excellent foliation, slaty cleavage. Breaks along parallel lines. Low grade metamorphism. PARENT ROCK IS SHALE.
Schist
Coarse grained foliated metaphoric rock. Higher temp and pressure. PARENT ROCK IS SLATE.
Gneiss
Course grained banded metamorphic rock. High grade metaphorphism. PARENT ROCK IS A SCHIST.
Non-foliated
Quartzite, Marble
Quartzile
Metamorphosed sandstone
Marble
Metamorphosed limestone
Rock Cycle
All rocks can change into other types. One rock type has never been the same type.
Relative Age Principles:
- Uniformitarianism: The present is the key to the past
- Principle of original horizontality
- Stratigraphic superposition: Younger rocks overlap older rock layers.
- Cross-cutting relationships. Anything that cuts something is younger.
- Faunal Succession: The observed changes in life forms occur in a definite and recognizable order through time. Species change through time and only exist for a short time.
The Great Unconformity
The gap in the rock record between cambrian times
Relative Time Scale
The process of correlation has allowed us to place all of the world’s rocks into a relative time scale.
Cenozoic
Age of mammals
Mesozoic
Age of giant reptiles. And birds.
Paleozoic
Explosion of life. Huge amounts of diversity. Intvertebrates, fish, reptiles, insects, vascular plants
Precambrian
Low diversity of life. First single celled organisms. Simple plants, worms, jellyfish.
How was the relative time scale developed?
Fossils, faunal succession
Kaibab
Sandy limestone - permian age - bathtub ring
Coconino
White sandstone cliffs - old sand dunes. Seperated by a layer of trees.
Red Wall
Mississippian Age - Abundant marine fossils
Absolute Time
Putting numbers on rocks, estimates of the earth’s age
Ideas of earth’s age
salinity of oceans, heat loss, thickness of sedimentary rocks, radioactive decay
Geologic Time Scale
Orginally based on fossils - now based on radioactive decay
Precambrian (time)
4.6 billion years to 570 million years. Comprises of 80% of earth’s time.
Paleozoic (Time)
540 million years to 250 million years. (explosion of life)
Sill
Tabular intrusive body of igneous rock that is parallel to surrounding layers
Declination
the angle bewteen magnetic north and true north
Cornices
Overhanging snow on the crater rim
Mesozoic (time)
250 million years to 65 million years. (dinosaurs)
Tree casts
empty space that used to have a tree
Lava tube
Conduits through which lava travels beneath the surface of a lava flow
Unconformity
- Deposition
- Uplift and erosion
- Deposition
- Uplift
- Unconformity
Tephra
Bombs and ash, anything that is thrown into the air during an eruption
Composite volcano
Alternating layers of lava flows and ash. Tend to erupt explosively.
Mount St Helens is:
Most active volcano in cascade range
MSH progression
March 20th - earthquake recorded, three days another occurred, March 25th, fractures developed on the glacier surfaces and a number of avalanches and rockfacks occurred. North flank bulge. Largest landslide in history.
MSH Eruptive History
formed about 40,000 years ago, nine main pulses of pre-1980
MSH Ash flow
Ash and steam begin to rise vertically. The ash column reached an altitude of more than 12 miles.
Features of sea floor
Long continuous mountain chains, trenches (deep valleys), continental shelves, abyssal plains.
Age of sea floor
200 million years
Sea Floor Spreading theory
- The sea floor moves laterally away from the ocean ridges (spreading centers)
- Magma rises up to the sea floor ridges
- The magma hardens to form a new seafloor
- The ridges crack in half and move away from each other
Evidence that supports seafloor spreading
- The age of the seafloor
- Seafloor sediment thickens away from the ridge
- Valleys run down the center of the ridges
- Paleomagnetism
Paleomagnetism
magnetic polarity stripes on the seafloor
How do polarity stripes form?
as basalt cools at the ridges, it preserves the polarity of earth’s magnetic field.
Three compositional layers
crust, mantle, core
Crust features
- Made up of oceanic and continental crust
- 6 to 25 miles thick
- covered by sediment and sedimentary rock
Mantle features
- makes up about 80% of the earth
- made mostly of olivine
Lithosphere features
100 km thick, rigid, strong, cold, brittle, less dense
Lithosphere
Contains the crust and a small amount of the upper mantle
Asthenosphere features
100 to 300km, plastic, pliable, weak, hot, flows, more dense
Theory of plate tectonics
- The surface of the earth is covered by 7 large lithospheric plates
- These lithospheric plates travel in directions that differ from different adjacent plates
How are lithosphere plates created?
at ocean ridges and slide over the asthenosphere
elastic rebound theory features
- If a rock is stressed it can store up its energy elastically
- When the strength of the rock is exceeded the rock breaks (brittle)
- The rocks on either side of the fault snap back to their orginial shape and release the stored energy
What do seismographs rely on?
Inertia
geophone
a device that converts ground movement into voltage which can be recorded
properities of waves
- wavelength
- amplitude
- period
- frequency
classification of seismic waves
body waves and surface waves
body waves
pass through the earth and travel outward in all directions from the focus
surface waves
- travel along the surface of the earth
- travel more slowly than P and S waves
- last wave to be detected
types of body waves
p wave (primary, compression) and s wave (secondary, shear)
P-wave
- consist of alternating pulses of compression and expansion
- produce changes in volume and density
- travel through solids, liquids, and gases
- motion of the wave is parallel to its direction
s-wave
- shear waves
- motion is perpendicular to direction
determining the location of the epicenter
- measuring the time interval between P and S wave arrival
- three seismic stations are needed
How is magnitude calculated?
measuring the height of the largest S wave
effects of an earthquake
1) ground motion (destroys buildings)
2) faults (breaks the ground surface)
3) fire - gas lines break
4) landslides, avalanches
5) liquefaction
6) tsunami
7) flooding
8) differential ground settlement
seismic gap
- location where a earthquake hasn’t occured in a long time
- areas where built up stress has not been released
stress
push or pull on a rock
strain
deformation - the measure of change in shape to a stressed material
types of deformation
- elastic (reversible)
- ductile (flow)
- brittle (breaking)
Continental drift theory
Alfred Wegener’s theory stating the world used to all be connected but drifted
Evidence for continental drift
Identical: continents, fossils, mountains, age of rocks, glaciated areas, ice flow
divergent margins
places where new oceanic lithosphere is created
origin and evolution of divergent boundaries
1) begin as rift zones on the continents - pulling apart of continental crust
2) as the continent is pulled apart, basaltic magma is extruded into the rift valley (oceanic crust is being formed)
3) the valley floor sinks and is filled with sea water
4) divergence continues and results in a large ocean basin
examples of divergent margins
- mid-atlantic ridge
- iceland
physical aspects of divergent margins
- state of stress (tensional or pulling)
- earthquake activity ( abundant, low magnitude, shallow depth)
- volcanism (intense volcanism, basaltic)
oceanic - oceanic crustal convergence
one lithospheric plate turns down into the earth and is recycled
physical aspect of oceanic-oceanic crust convergence zones
- state of stress (compression)
-earthquake activity (abundant, follows the down going slab - shallow and deep, high magnitude earthquakes)
-volcanism (abundant)
examples of oceanic-oceanic crust convergence
- Japan
- aleutian islands
oceanic - continental crust convergence
oceanic crust dives beneath the continental crust
features of oceanic - continental
- trench - location of a subduction zone
- continental volcanic chains
physical aspects of oceanic-continental crustal convergence
1) stress (compression)
2) earthquakes (shallow to deep, lots of them, high magnitude)
3) volcanic activity (abundant)
examples of oceanic to continental
- West coast of south america - andes
- Cascades
continental - continetal
continents are buoyant and don’t subduct ( continental collisions)
features of continental-continental crustal convergence
- double thickness of continental crust
- huge mountain chains
physical aspects on continental-continental crustal convergence
compression, earthquakes (high magnitude, shallow), mountains
examples of continetal crust collisions
- himalyas
- alps
- appalachians
hot spots
- heat anonomly in the asthenosphere
- magma makes its way to the surface from deep depths
Examples of hot spots
yellowstone, hawaiian islands
mechanisms of plate tectonics
- convection of the mantle
- slab pull
shear
a stress which is applied horizontal or tangential to the face of a material
remanant magnetism
rocks can preserve a “fossil” record of the earth’s magnetic field
earth’s magnetic field
the earth behaves as if there is a giant magnetic bar inside
Types of magnetic information
polarity, declination
normal polarity
todays magnetic field
paths of apparent polar wandering
ancient rocks, layered rocks and diff continent rocks
does the earth’s magnetic pole wander?
NO, the continents wander, not the magnetic poles
dipping bed
a layer of rock that is not horizontal
strike
is a line representing the intersection of that feature with a horizontal plane
dip
The dip gives the steepest angle of descent of a tilted bed or feature relative to a horizontal plane
anticline
a type of fold that is an arch like shape and has its oldest beds at its core. Older towards center of the fold.
syncline
a type of fold that has its younger layers closer to the center, lower than a anticline
how to read a seismogram
first p waves, then s waves, then surface waves
distance between p and s waves
can be used to determine the distance between the station and the earthquake
passive margin
transition between oceanic and continential lithosphere that is not an active plate margin.
mechanism for plate tectonics
convection currents beneath the plates move the crustal plates in different directions. - thermal convection
transform features
shallow earthquakes, shear stress, no volcanism
1989 Loma Prieta
6.9 magnitude, 63 deaths, 3757 injured
2011 Sendai Earthquake
9 magnitude, around 20k deaths
Seismograph
Instrument that detects vibrations and shaking of earth
Where do Texas earthquakes occur?
El Paso, Panhandle
Flow failure occurs at:
A slope > 3º
The west coast of North America is comprised of what 2 plate boundaries? (Alaska & California)
Convergent boundary of Alaska, Transform boundary in California (strike-slip)
A portion of the East Pacific Rise was
Subducted under California
As the Atlantic basin opened, North America…
Moved westward into pacific basin
When and how did The Great Alaskan Earthquake occur
1964, pacific plate moved northwestward and subducted under the North American plate
The Great Alaskan Earthquake magnitude:
9.2
Characterize of the San Andres Fault
Some parts locked (>7) , some parts creeping (weak, 5-6), Earthquakes occur in clusters, separated by long periods of quiescence
Epicenter of Alaskan Earthquake
Prince William Sound, 75 miles east of Anchorage Alaska
Intensity of Alaskan Earthquake
3-10, felt over 700,000ft of Alaska and Canada
Aftershocks of Alaskan Earthquake
In the first day, there were 11 smaller earthquakes > M 6!
Cause of the Alaskan Earthquake
NW motion of the Pacific plate of about 5 to 7 cm/yr, compression relieved by sudden SE motion of the portions of the Alaskan coast back over the subducting slab, pacific plate moved under the north american plate
Effects of Alaskan Earthquake
Montague Island was raised by 25 feet, quarter mile of the seafloor lifted above sea level, Portage was dropped by 9 feet
Damage of Alaskan Earthquake
Landslides, avalanches, liquefaction, tsunamis, and extreme ground shaking, 122/131 were killed by the tsunami (16 in oregon/cali), Low population density, holiday, wooden buildings survived shaking
Tsunami of AE height
12 ft
Liquefaction of AE
Flow failure occurred in Seward
Seismic waves of AE
Texas and Louisiana felt it with 4in of vertical motion and sunk boats
The Great 1906 San Fransisco Earthquake
265 miles of fault ruptured, locked segment, depth of 12.5 miles
Magnitude of SFE 06
8
Intensity of SFE 06
7-9, shaking was more intense in areas of weak consolidated materials around the bay
Duration of shaking for SFE 06
60s for 10-25ft to slide past eachother
Foreshock of SFE 06
Small earthquake felt 30s before
Ground Movement of SFE 06
horizontal offset on the surface was about 20 feet
Damage of SFE 06
> 3K deaths, 225K homeless, 28K buildings destroyed, FIRE WAS MOST OF DAMAGE
The World Series Earthquake 1989
Loma Prieta, just before Game 3
Location of WSE
60 mi from San Fran, 25 miles ruptured
Magnitude of WSE
7.1
Intensity of WSE
6-9
Aftershocks of WSE
M 5.2 aftershock occurred 2.5 min after the main shock, thousands of smaller quakes occurred in the next two weeks
Duration of shaking for WSE
11s
Damage of WSE
67 deaths, 4K injured, 12K homeless, most people killed on a section of highway I-880 that collapsed
Tectonic setting of California
North American plate is sliding SE of the Pacific plate
Three types of porosity
Solution cavities, intergranular porosity, fracture porosity
Solution Cavities
Large pores formed by the dissolution of rock - usually forms in limestones
Sinkholes
Solution cavity that opens to the surface
Karst Topography
Solution cavities create caves, landscape dominated by sinkholes
Groundwater flow
Moves with pressure to where water table is low, FLOWS DOWN POTENTIAL, originates from precipitation
Potential Surface
Differences in the elevation of the water table creates a pressure surface (in unconfined aquifers the potential surface is the water table)
Cone of Depression
a conical depression in the potential surface
The shape of the water table
Mimics the grounds surface and moves with rain
What is the direction of groundwater flow for FL?
All directions
Stream
the part of the hydrologic cycle that returns water to the oceans on the lands surface
Two components of streams
Water and sediment
Drainage Basin
an area from which all precipitation flows to a single stream
Parts of a river system
Tributaries, Main Trunk, Deltas
Tributaries
collection, a dendritic pattern of smaller streams that feed water into the main trunk
Main Trunk
Transports water
Spring
A place where groundwater discharges at the Earth’s surface
Deltas
Disperse, river water flows into a standing body of water
The number of tributaries decrease:
Downstream
Tributaries V:
Downstream
Longest rivers in the world:
Nile (4132), Amazon (4000), Yangtze (3915)
Longest rivers in US:
Missouri (2540), Mississippi (2340), Yukon (1980)
The stream gradient decreases:
Downstream (relief of land)
Stream competence decreases:
Downstream (grain size)
Discharge INCREASES:
Downstream
Discharge
V/t that passes through a stream
Stream discharge=
Velocity x Cross Sectional Area
Hydrograph
a graph that shows discharge over time
Build house on
TERRACE
Origins of topographic depressions
Glaciers (kettle), Volcanoes, Faults
Two types of lakes
Oligotrophic and Eutrophic
Oligotrophic
Poorly-nourished, few plants and a lot of O
Eutrophic
Well-nourished, high Nitrogen and Phosphorus output (unhealthy)
July 2021 European Floods killed:
242
Base flow
A portion of the stream flow that is not runoff; it is
water from the ground, flowing into the channel
Lateral spread occurs at
0.3 to 3º
Ground Oscillation
Slope is too gentle to permit lateral movement
Blocks of soil may decouple and begin to shake
Fissures open and close
Sand boils up out of the ground
Tsunami
A series of sea-waves generated by an undersea disturbance
Causes of Tsunamis
Earthquakes, landslides, volcanic eruptions, explosions, and meteorite impacts MOST COMMON IS VERTICAL DISPLACEMENT OF SEAFLOOR
When a tsunami approaches land it:
slows down, amplitude increases
Tsunami Warning System
UNESCO 2006, consists of 25 seismographic stations and tidal gauges (DART)
The Indian Ocean Tsunami
Deadliest tsunami ever, 230,000 killed across 14 countries, earthquake was 9.1 (3rd largest) and shook ground for 10 min
East Japan Earthquake (2011)
9.03 (5th largest), Earthquake moved Honshu 8ft to the east, 15,882 dead and 6,142 injured, Sendai got 6mi inland
Outwash
sand and gravel deposited in front of a glacier
Till
unsorted, unstratified sediment deposited in contact with a glacier
drifts
`glacial deposits are all called ___________ because of the misconception that they were deposited by icebergs; material associated with glaciers
erratics
boulders unlike the bedrock on which they lie
glacial theory
ice once covered large parts of the continents that are now ice free
fjord
glaciated valley inundated by seawater
Horn
pyramidal peak where three or more cirques intersect
Bergschrund
a split or crevasse in the ice of a glacier, where the glacier detaches itself from the mountain’s rock; forms at the back of a cirque
cirque
bowl-shaped depression with a steep headwall
glacial valley
U-shaped landform created by alpine glaciers
outwash plain
vast flat areas underlain by sand and gravel
esker
sinuous ridge of sand and gravel deposited by rivers under, on or within the ice
moraine
a ridge of till that forms at the snout of a continental glacier
