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94 Cards in this Set

  • Front
  • Back
Molton rock ON surface
Molton rock BELOW surface
4 Heat sources for melting rock
Temperature increase with depth, frictional heat from plates moving, decay of radioactive minerals, mantle plumes
Does increasing pressure cause melting temperature to increase or decrease?
What does water make the melting temperature do?
What is the primary constituent of magma?
Felsic Magma
high in silica, thick and pasty, doesnt flow and is very explosive
Where does Felsic magma form?
Convergent PB
Mafic Magma
silica poor, high in Fe/Mg and flows easily
Where does Mafic Magma form?
subduction zones
What controls magma/ viscosity?
silica content and temperature
Intermediate magma forms where?
convergent pb and subduction zones
Where are ferromagnesian silicates located?
the discontinuous side
Where are plagioclase silicates located?
the continuous side
Which side does one mineral change to another at a specific temperature?
discontinuous side
Which side does basic feldspar crystal remain the same?
continuous side
Crystal Settling
FeMg minerals fall to the bottom of the magma chamber
melting the country rock
Enchanted Rock
intrudes parallel to sedimentary rock layers
cuts across sedimentary rock layers
Devil's Tower and Shiprock
volcanic neck
intrudes in a mushroom-like shape between sedimentary layers
What determins magmas ability to erupt?
viscosity and gas content
Which type of magma rises and erupts at the surface?
Mafic magma
Whcih type of magma cools underground to form plutonic rocks?
Felsic magma
Most abundant gas relased and blows magma apart
water vapor
first gas to fizz out of magma
carbon dioxide
lava flow with a ropy surface
lava flows as rough, jagged blocks
Columnar joining
laval flow cools and shrinks forming hexagonal columns
Nuee Ardente
pyroclastic flow that rushed down slope at hurricane speeds in an incandescent flowing cloud
Where is a Nuee Ardente common?
Composite Cones
mudflow that is the deadliest hazard
Shield Volcano
low, rounded profile and mafic lava erupts quietly
cinder cones
formed by pyroclastics falling around the vent
Composite Volcanoes/Stratovolcanos
MOST COMMON, both pyroclastic and laval flows, forms at convergent pb and subduction zones
bowl shaped pit centered over the vent at the top of a volcano
Lava domes
formed by silica lava that is to thick to flow and extrudes out over the vent
depression formed by the collapse of "cone" into the empty magma chamber below
What does the most catastrophic event on earth form?
A caldera
Resurgent Caldera
formed by renewed surges of magmat into a caldera
3 examples of a resurgent caldera
long valley, CA
Valle Grande, NM
Fissure Eruptions
type of eruption that flows out of a long crack
Example of a fissure eruption
Columbia River Plateau
Last Gas to fizz out of magma
water vapor
Welded tuff
Name of the ash flow deposits that erupted from fissures during caldera formation
4 ways to predict an eruption
Plate tectonic locations, harmonic tremor, physical and chemical changes, eruptive history
Circum-Pacific Belt
ring of fire
where most the the volcanoes in the world are located
involves the physical breakdown and alteration at/near the surface
involves transportation by wind, water, glaciers, etc.
Differential weathering
non homogenous rocks weather into bizarre sandstone forms
Mecahnical weathering
rocks decomposed by alteration of parent rock (rock change)
Name mechanical weathering processes
1) frost action
2)preserve release
3) thermal expansion and contraction
4) root wedging
5) activities of organisms
Exfoliation domes
formed when batholiths undergo pressure relase

(large rounded areas)
a part of chemical weathering where water removes ions from rocks and carries them in solution
Carbonic acid
formed by water and carbon dioxide
when Fe and Mg silicates are chemically altered. FeMg silicates combine with oxygen to form an acid.

If water is present - Limonite
Weathers potassium feldspar. The end result is 1) clay
3) potassium in solution
Bowen's Reaction series least and most stable
Least- Olivine
Most - Quartz
Spheroidal weathering
edges and corners of angular rocks weather into rounded boulders
Soil regions
climate is the most important factor of formation
Major Soil Types
1) pedalfers - Fe and Al oxides present, good agricultural soil

2) Pedocals - arid, evaporating waters enrich in CaCO3

3) Laterites - tropical, only deep red A horizon, slash & burn
Changes sediment into rock by two processes
1) compaction - weight of overlying rock
2) Cementation - minerals precipitated in pore spaces binding particles together
Most common clastic rock
Quartz sandstone
Most common chemical rock
Limestone & dolostone
Sea level rising

sea level falling

When are sedimentary structures formed?
at the time of deposition
What do sand dunes in deserts show?
Cross bedding
Symmetrical ripple marks
waves going back and forth

Know the picture
asymmetrical ripple marks
currents in one direction

know the picture
formed by drying out and shrinkage of clay
Where are fossils found?
Sedimentary Rocks
What is coal composed mainly of?
Steps in forming coal
1) swams rich in plant life
2) plants accumulate slowly and form peat
3) decompose in an oxygen poor environment
4) undergo heat and pressure
What is hydrocarbon composed of?
Hydrogen and Oxygen
List steps for hydro carbon formation
Accumulation of algae and microorganisms in shallow seas

burried quickly by silt/mud

oxygen deficient envoronment so doesn't rot

heat and pressure forms
Vesuvius, Italy
79 AD

Destroyed Pompeii and Herculaneum

Subduction of African plate under European plate
Krakotoa, Indonesia
loudest noise recorded in history

Tsunami killed 36,000

Located in Circum-Pacific Belt
Tambora, Indonesia
Larges and deadliest eruption

"year without a summer"

Gloomy weather set mood for frankenstein

Located in Circum-Pacific Belt
Paricutin, Mexico
Cornfield volcano
studied birth to death

Subduction of Cocos plate under N. American plate
Mount Pelee, Martinque
St. Pierre - town wherenuee ardente killed 28,000 villagers
Killed voters

Subduction of N. American plate under caribbean plate
Heimaey, Iceland
Control lava flow - saved town & port

Divergent plate motion along Mid-Atlantic ridge
Lake Nyos, Cameroon, Africa
cloud of carbon dioxide killed villagers and cattle
active and sit above subduction zone
-Erupt andesite
-Subduction of Juan de Fuca plate under N. American plate
Mt. Rainer, Washington
Most dangeroud volcano in U.S.
-Lahars will reach populated areas of Pugent Sound
Mt. St. Helens
erupted in 1980
millions of trees blown down
spirit lake changes

Hazards- Nuee Ardente, ash, lahar, and avalanche
Mt. Shasta, Cal.
Largest volcanoe
Crater Lake, Oregon
Mt. Mazama - volcano that erupted

Formed a caldera
Valle Grande, NM
Resurgent caldera

Resurgent caldera on w. side of Rio Grande rift

Anasazi carved homes
Bandelier tuff
Long Valley, Cal.
Resurgent caldera
Most likely to have major eruption and most active volcanic area

Warning signs - dome swelling, fumaroles and hot springs, earthquakes, carbon dioxide kills trees
Yellowstone, Wyo.
resrugent caldera
Sits above a hotspot
erupted 3 times

Warning signs - mud pots, geysers, carbon dioxide kills forest and animals uplift/subsidence of ground, earthqueakes
2nd most active area in the world

Subduction of Pacific plate under NA plate