Term
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Definition
"Failed rift"
That will channel major rivers into the new ocean and slowly become filled with sediment. |
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Definition
| Africa's west coast where the Niger Rivers comes to the Atlantic Ocean |
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Northwest Pacific
Confirmed by similar kinks of identical age in adjacent hotspot trails
Demonstrates present movement of the Pacific plate towards the northwest (Hawaiian Islands) and previous movement towards the north (Emperor Seamounts) |
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one of the worlds most active volcanoes... on the flanks for Mauna Loa
is a huge CALDERA |
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Definition
| on Maui last erupted in the late 1700's |
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Definition
| Hawaii's other active volcano |
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Definition
| tends to fill the caldera during the dying stages of an Hawaiian Volcano |
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Definition
| will one day become the newest member of the island chain as the islands move northwest |
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Definition
worlds biggest mountains
more than 50 extinct volcanos |
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Definition
dormant for 3600 years
worlds tallest mountain... raising 33,000 ft from the seafloor
worlds largest single mountain... volume of 40,000 cubic km |
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Definition
| First suggested that the hotspot was result of a "mantle plume" |
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Definition
| first suggested in the 1960's that they reflected the presence of a "hotspot" beneath the plate and were therefore younger than the adjacent ocean floor |
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Definition
| develop when lave rises sufficiently fast that the gases dissolved in it do not have time to escape fore it reaches the surface so that frothing and eruption occur simultaneously |
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Definition
| may extend many tens of km from the vent... tunnels that later drain to produce lava tubes |
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Definition
cool lava form
either blocky or ropey surface textures |
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Definition
| freezing lava against tree trunks which later rot away |
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Definition
| appears rubbly and forms when the solidified surface is broken up by lava flowing beneath |
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Term
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Definition
| blocky flows of lava that pile up and could explode |
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Term
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Definition
blocky flows that land aerodynamically sculpted
resembling teardrops, hair, or cow dung |
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Term
| Ropey Lava aka "pahoehoe" |
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Definition
Lava flow like "honey"
produce rope like folds |
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Term
| Typical volcanic sequence: |
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Definition
1) volcanic island
2) fringing reed
3) atoll
4) seamount |
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Term
| Island Park Caldera was created by? |
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Definition
Huckleberry Ridge Tuff
magma exploded 1.3 million years ago |
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Term
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Definition
| 600,000 years ago created by the explosion |
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Term
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Definition
| Gas-like magma less dense but more viscous than basolt, so that it rises more rapidly but holds its gases allowing pressures to build explosively |
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Definition
| the ground above the magma chamber cracks, releasing the pressure and triggering a catastrophic eruption |
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Definition
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Term
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Definition
| channels send water and steam directly to the surface |
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Definition
| Silica deposits left behind as the mineral-charged water cools at the foot of the geyser |
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Term
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Definition
| subrerranean pools may absorb the boiling water and form hot springs |
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Term
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Definition
| when a trickle of water reaches the surface, strong acids turn the soil into bubbling mudpots |
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Definition
| steam vents or fumaroles if all the water boils off below |
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Definition
| at Mommoth Hots Springs, hot water dissolves subterranean limstone |
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Definition
| mineral-charged water as it cools and calcium carbonate precipitates |
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Term
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Definition
most spectacular spring
building terraces of travertine colored by bacteria |
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Term
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Definition
| Where 2 plates struffle to slide past eachother, the boundary between them is a fracture in the crust |
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Term
| Transform Fault sequence: |
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Definition
if the rocks along the fault lock while:
1) the STRESS from plate motion continues;
2) STRAIN builds up in the rocks on either side of the fault so that they;
3) DEFORE/bend, storing up elastic energy like a spring ever drawn tighter
4) when the spring snaps, rocks on either side of the fault jerk violently past each other and earthquake shock waves are sent out in all directions
the crust is neither created nor destroyed
fault between them is called "STRIKE SLIP FAULT"
- not all SSF's are plate boundaries, but those are ARE plate boundaries are called, "TRANSFORM FAULTS" |
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Term
| What Transform Faults intersect continents? |
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Definition
1) San Andreas Fault or California
2) Queen Charlotte Fault off the coast of British Columbia
3) Motagua Fault of Guatamala
4) Levant Fault beneath the Dead Sea
5) Anatolian Fault of Turkey
6) Alpine Fault of South Island, New Zealand |
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Term
| What happens at DIVERGENT BENDS? |
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Definition
the curst may be stretched ntil it breaks and collapses to creat a long, narrow depression or "Pull-apart Basin" that may collect sedument of become filled with water
Examples:
1) Dead Sea
2) Salton Sea |
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Term
| What happens at CONVERGENT BENDS? |
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Definition
the faults curves in the other direction (than divergent bends)
the plate motion jams the blocks of crust together creating folded mountains or "TRANSVERSE RIDGES" across the trace of the fault |
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Term
| Californias Transverse Ranges |
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Definition
North LA...
occur at a convergent bend in the San Andreas fault |
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Definition
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Term
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Definition
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Definition
- 40 million years old
- slices through Guatamala, 150 miles
- forms the boundary between the N.A. and Caribbean Plates |
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Term
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Definition
- Middle East
- Old Testament refers to the movement on this fault |
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Term
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Definition
- lines within the "Dead Sea Rift" between Jordan and the West Bank
-a PULL-APART BASIN produced in a region of tension between two overlapping stike-slip faults
-Seperate the Arabian and African Plate |
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Term
| When the far side of each fault moves to the left/right so that the stike-slip fault is termed? |
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Definition
Left-Lateral or Sinistral
Right-Lateral or Dextral |
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Term
| What forms an extension of Africa's rift system? |
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Definition
| the Levant fault or DEAD SEA TRANSFORM |
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Term
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Definition
| Evaporation near the shore |
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Term
| residue of valuable minerals from water evaporation from the Dead Sea is? |
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Definition
Potash - which is mined for fertilizer
Amber gas BROMINE is also extracted from bromide salts |
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Term
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Definition
- Turkey
- forms the northern boundary of the Anatolian Plate |
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Term
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Definition
- Canadian Appalachians slices through the cent of Nova Scotia
- RIGHT-LATERAL transform fault
- Active during the assembly of Pangaea in the Paleozoic |
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Term
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Definition
- Scotland
- lies upon part of an ancient transform fault torn asunder with the opening of the Atlantic Ocean |
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Term
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Definition
- California
- active, RIGHT-LATERAL movement
- 1857 Fort Tegjon Earthquake help form...
- April 1906 - 18 feet of movement on the San Fran segement produced one of the worst earthquakes in U.S. history |
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Term
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Definition
- 8.3 magnitude
- rippled the ground waves 1 meter high
- 20 meters from crest to crest
- Destroying buildings at least 20 miles from the fault |
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Term
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Definition
- 1971
- 6.5 magnitude
- half a billion dollars in damage |
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Term
| Vibrations of an earthquake being where? |
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Definition
| at the Focus or Hypocenter - where a locked fault suddenly lets go |
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Term
| What are Primary or P-Waves? |
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Definition
- speed along at 12,000 to 19,000 mph to arrive first at the surface or at the seismic wave detection devices known as seismometers
- Compressional waves (like sound) alternately pushing and pulling surface structures in the direction of wave travel
- P waves set the air motion as they leave the Earth's surface, creating the "roar" that comes with the earthquake |
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Term
| Seismic wave detection devices are known as what? |
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Definition
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Term
| What are Secondary or S-Waves? |
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Definition
- slower, moving at 7,000 to 10,000 mph and arrive second.
- 'Shear' waves like oscillations in a rope
- heave the ground up and down or sideways but CANNOT travel through water |
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Term
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Definition
| - produce low-frequency vibrations that roll the ground like ocean waves or whip sideways |
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Term
| What is the point on the Earth's surface nearest the focus? |
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Definition
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Term
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Definition
- logarrithmic scale - each unit increase stands for an increase of 10 times the seismic wave measured by the seismograph
Example:
magnitude 8.3 is a MILLION times bigger than 4.3 ( 32 x 32 x 32 x 32) |
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Term
| City most susceptible to potential earthquake is? |
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Definition
San Francisco
- lying between the locked San Andreas fault and the Hayward Fault which moves at over 1cm/yr |
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Term
| "World Series" earthquake |
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Definition
- 1989
- generated magnitude 7.1 earthquake, east of Santa Cruz in the Santa Cruz mountains |
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Term
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Definition
| help geologist to identify a threatening "SEISMIC GAP" |
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Term
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Definition
| Occurs when ciolent shaking of water confined in the ground briefly turns the soil to quicksane so that building sink or tip and are locked askew when the shaking stops and the ground sets again |
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Term
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Definition
help predict earthquakes
examples:
- strange animal behaviors
- smaller tremors aka "Foreshocks" |
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Term
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Definition
| wires stretched across the fault to register any HORIZONTAL movement |
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Term
| what are Scintillation Counters? |
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Definition
| single the amount of the radioactive has RADON realsed into groundwater by rocks under stress |
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Term
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Definition
| - like those used to predict volcanic eruptions; they detect changes in land slope by the rising and falling of water levels in two containers |
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Term
| What are Laser-ranging Instruments? |
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Definition
| - measure the round-trip trave time of a light pulse and thus the precise distance between two points; indicating horizontal movement across the fault |
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Term
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Definition
| - uses quasar signals from outside our galaxy as reference points to monitor ground movement |
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Term
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Definition
| - measures plate movement by bouncing laser beams between Earth stations and an orbiting satellite |
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Term
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Definition
| - measure expansion and contraction of crustal rock, indicating stain accumulations or release |
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Term
| True or False. Geologist can now predict - when, where, and how big an earthquake will be. |
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Definition
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Term
| What is it called where 2 plates approach each other resulting in collision? |
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Definition
| convergent or destructive plate boundaries |
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Term
| During ocean closure, dense basaltic ocean floor is subducted beneath continental crust along what? |
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Definition
| subduction zone, marked by a deep OCEAN TRENCH |
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Term
| When continents meet head on, they meld together at a what? |
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Definition
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Term
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Definition
bits of stranded ocean floor
found:
- Alps
- Himalayas
- Appalachians
- other mountain ranges now far from sea |
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Term
| what are Island Acrs and what do they do? |
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Definition
- curved lines of volcanic islands
- they rise where two oceanic plates collide |
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Term
| what causes mini versions of mid-ocean ridges? |
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Definition
- molten rock in the mantle rises behind the island arc to create a small spreading zone
Back-arc spreading formed:
- the Sea of Japan
- Philippine Sea |
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Term
| Subduction also causes earthquakes, which in the Pacific, may generate what? |
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Definition
| - seismic ocean waves ("tidal waves") aka Tsunamis |
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Term
| the Pacific "RING OF FIRE" |
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Definition
- 48,000 km long
- 75% of the Earth's active land volcanoes tower above the offshore trenches that mark the lines of collision |
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Term
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Definition
- where melting is triggered by the addition of water and other volatiles from the subducted oceanic crust
Create a circle of volcanoes that include:
- Mount St. Helens
- Japan's Mt Fujiyama |
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Term
| Mantle-wedge that breaks through the ocean floor builds what? |
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Definition
| - Basalt ("mafic") island arcs |
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Term
| Mantle-wedge that punches through continents do what? |
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Definition
- become contaminated with Andesite ("intermediate") and Rhyolite ("felsic") magmas
ALL PRODUCED BY PARTIAL MELTING OF CONTINENTAL CRUST |
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Term
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Definition
- oceanic Nasca plate plunges beneath the continental S.A. plate
- this collision created a parallel mountain range, the ANDES |
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Term
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Definition
- the newer Western Cordillera which arose from volcanic eruptions as riding magma pods reached the surface
- Large and lie about 70 km apart |
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Term
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Definition
- eastern Cordillera
- raised by compressive defromation east of the high plain or "Altiplano"
- Smaller and lie close together |
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Term
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Definition
- western side of Chile
- produced giving rise to the coastal Atacama Deser |
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Term
| Where does N.A. experience active subduction? |
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Definition
| - where the Juan de Fuca or Gorda plate dives beneath the Cascade Mountains of Washington and Oregon |
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Term
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Definition
- in Washington State
- dramatic evidence of that subduction
- March 1980, seismic activity began, a sign that the small Juan de Fuca plate continues to thrust beneath the N.A. plate and magma continues to rise beneath the Cascade volcanoes.
- magnitude 5.0 |
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Term
| the Juan de Fuca plate was once part of what plate? |
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Definition
| Farallon Plate, fromed the floor of the eastern Pacific but which has now all but dissappeared beneath the overriding N.A. plate |
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Term
| What is Pyroclastic Flow or nuee ardente? |
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Definition
| - glowing cloud of white-hot ash |
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Term
| what has formed the Aleutian Islands? |
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Definition
| - subduction of the Pacific plate beneath the Aluetain Trench |
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Term
| What forms the north Pacific? |
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Definition
| - the triangular Kula plate |
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Term
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Definition
| - sits where the Pacific and Philippine plates dive under the Eurasian plate |
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Term
| Japan's arc is due to what? |
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Definition
- breaks in the subducting oceanic plates
- Japan is separated from Asia by a BACK-ARC BASIN, which forms the Sea of Japan |
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Term
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Definition
- volcanic continues
- Volcanoes:
- Mayon
- Taal
- Pinatubo |
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Term
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Definition
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Term
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Definition
- almost 7 miles deep
- Lowest place on Earth |
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Term
| What happens during Marianas-type subduction? |
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Definition
- very old ocean floor meets young ocean floor so that subduction is "passive" -- plates meet with less force
- angle of subduction is steep
- few major earthquakes
- roll-back of sinking plate is common -- creating back-arc basins |
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Term
| What happens during Chilean-type subduction? |
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Definition
- young buoyant ocean floor is "forced" to subduct -- plates meet with great force
- angle of subduction is shallow
- earthquakes are frequent and strong
- compression occurs -- creating trench-parallel mountains |
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Term
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Definition
- lies above the Tonga Trench and the Kermadec Trench which link up with the Alpine Fault transform plate boundary of New Zealand.
- Subduction is steep
- segmented Marianas-type |
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Term
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Definition
- on the Eurasian Plate above the subducting seafloor of the Indian-Australian Plate and adjacent to the Java Trench
- 100 active volcanoes |
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Term
| Krakatau represents what? |
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Definition
| - one of the greatest natural explosions in history |
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Term
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Definition
- largest eruption in modern history
- 1815, blew away the upper 4000 ft of the volcano and left a 6 km crater, hurled 80 cubic km of ash and dust into the air
- killed 12,000 people |
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Term
| What's the significance of the eruption of Tangkubanprahu? |
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Definition
| - southeast of Jakarta may have given rise to the ill-fated kingdom of Mataram in central Java by bringing famine ad a mass exodus from western Java sometime in the first millenia after Christ |
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Term
| What caused central Java to be buried in ash? |
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Definition
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Term
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Definition
- Mediterranean eruption
- 1500 bc
- Once formed part of the Hellenic arc, north of Crete
- Aegean Island of Santorini is all that remains of this volcano
- Produced by the subduction of the African Plate beneath the Agean seafloor, south of Crete
- this eruption coincided with the mysterious end of the Minoan civilization |
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Term
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Definition
- coincides with the exodus of the Children of Israel from Egypt
- may lie at the center of the legend of Atlantis, the empire described by Plato that was swallowed up by the sea |
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Term
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Definition
- Mediterranean eruption
- AD 79 -- resulted in the destruction of the Roman commercial centers and vineyards of Pompeii and Herculaneum |
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Term
| The events of Aug 25th and 26th AD 79 were recorded by who? |
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Definition
| Pliny the Elder, who commanded the Roman fleet at Misenum and sailed across the Bay of Naples to the port of Stabie |
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Term
| what is Phlegrean Fields? |
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Definition
- active volcanic region
- highly built-up region rich in hot springs and health spars |
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Term
| Who proved the slow and genlte nature of geological processes? |
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Definition
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Term
| what is the N. American Cordillera? |
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Definition
| - over 70% of the mountains of western N.A. have been added or "accreted" to N.A. over the past 200 million years |
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Term
| when the dinosaurs lived the coast of N.A. laid where? |
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Definition
| - along the present Continental Divide - as a broad continental shelf like that of today's eastern seaboard |
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Term
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Definition
| - rocks of the old continental shelf that were folded and faulted, and piled up on top of each other |
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Term
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Definition
| Overthrust Belts - which old rocks are pushed over young, reversing the normal rule of stratigraphy |
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Term
| what is the western overthrust belt? |
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Definition
- part of the N. American Cordillera
- collisions with Pacific-derived suspect terranes during the Mesozoic and Cenozoic have shoved parts of the Rocky Mts 65 km eastward |
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Term
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Definition
- sediments of the overthrust belt
- are experienced rising pressure and heat which slowly cooked the organic remains into a brew gas, salty water and oil droplets |
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Term
| what forms an oil reservoir? |
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Definition
when a slab cracks and rides over itself, the result is an overthrust... then great pressure can push oil and has up through porous sandstone until both are trapped beneath an anticline of impermeable rock to form... oil reservoir
permeable = leaky
porous = holey
impermeable = sealing |
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Term
| what was once part of the eastern overthrust belt? |
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Definition
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Term
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Definition
- an island arc array
- created when Europe and Africa started to collide with N.A |
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Term
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Definition
- forerunner to the Atlantic
- closed by Africa |
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