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Geology test 1
geology test
26
Geology
Undergraduate 2
02/08/2011

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Cards

Term
What are the two types of crest 
Definition
Oceanic and Continental Crust 
Term
The lithosphere is comprised of which layer or layers
Definition
oceanic crest and contninetal crest and upper mantle.
Term
What are the three zones into which the manlte can be divided  
Definition
Upper Mantle,Ashthenosphere,lowerMantle
Term
What is lithosphere 
Definition
the plates are compress of the relatively rigid outer shell of earth
Term
What is tectinoc forces 
Definition
the forces that generated inside the earth
Term
What is the the theory of plate tectonics
Definition
plates thectonics theory hold that the earth lithosphere is divided into rigid plates that move over the asthenosphere and diverge ,converge and/or slide past each other as they move.
Term
What are the 3 types of plate boungaries and how they take place
Definition

divergent boundary - involes two plates that are moving apart from each other. 

convergent boundary - plates move towards each other.

transform boundary - plates slide past one another. 

Term
What are three types of covergent boundaries 
Definition
Ocean-continent, Ocean-ocean, Continent-Continent
Term

Why are convergent plate boundiers strongly associatal with geological disaster

Definition
because it cause a ocean trenches wich cause earthquakes and volcano.
Term
What happens when two continents coverge
Definition
one goes under and creates mountain range at where the colligen take place 
Term
What happens at oceanic - continental convergent plate  boundery
Definition
in the region where the top of the subducting plate slide beneath the an asthenosphere. Melting takes place and magme is created 
Term
describe the different between continental crust and oceanic crust
Definition
Continental crest is thicker then oceanic crest.
Term
What is the Ashenosphere why is it important 
Definition

  • A redion of the earth outer shell beneath the lithosphere.
  • It may represent a zone where magma is likely to be generated.
  • The rocks here may have ralatively little strengh and therefore are likely to fow.

Term
How does the lithopshere differ from the aesthenosphere
Definition

  • Lithosphere is solid and is made up of the crest and upper mantle.
  • Asthenosphere in under the lithosphere and it isnt soild or liquid chute of the tempeture and pressure.

Term
What is the mohorovicic discontinuity
Definition
it is the boundary that separates the crest from the mantle seneath it 
Term
Describe seismis-wave shadow zones and what they indicate about the earth's interior
Definition

  • It indicates that s-waves do not travel through the core at all.
  • It implies that the core of the earth is a liquid or at least acts like liquid.

Term
Describe the ULVZ zone at the core-mantle boundary
Definition
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.
Term
explain how the earth's spinning inner core plays an impoetant role in the generation of the earth magnetie field.
Definition
because the magnetic lines of force panetrate and connet both the inner and outer core a faster rate of rotation of the inner core would play an important role in the genertion of the earth magnetic field.
Term
What is geothermal gradient
Definition
temperature increase with deoht into earth.
Term
What evidence have shown that the mantle is solid not molten and that geothermal gradient is as low as 1c per kilometer and not 25c per kilometer within the mantle.
Definition
Seismis evidence 
Term
What is earth magnetic field ? What ia a magnetic reversal
Definition

  • Region of magnetic force the surrounds the earth. 
  • a change in the polarity of the magnetic field.

Term
explain how magnetic anomalies are applied to stuy in geologic structures and ore detections.
Definition
A body of magnetile ore (a highly magnetic ore of the matal iron) has been emplaced in a limestone by hot solutions rising along a fracture. The magnetism of the iron ore adds to the magnetic field of the earth a strong magnetic field at the surface
Term
What are positive and negative magnetic anomalies 
Definition

  • positive - reading of magnetic field strength that is higher the regional average
  • negative - a reading of magnetic field strength that is lower than the reginal average.

Term
Isostatacy
Definition
is the balance or equilibrium of adjacent blocks of brittle lithopshere " floating on the asthenosphere.
Term
Isostatic Adjustment
Definition
 concept  of vertical movement of section of the earth's crest to achieve balance or equilibrium.
Term
Crustal rebound 
Definition
The rise of the crusted liosphere after the removal of the ice 
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