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EOS 11 Test 2
Rocks for Jocks..
17
Geology
Undergraduate 3
11/05/2008

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Cards

Term
mafic rock
Definition
rich in iron and magnesium
Term
silicic rock.. order of silicic->mafic
Definition
rich in silica.. silicic, intermediate, mafic, ultramafic
Term
layers of Earth
Definition

crust: silicic (continental), mafic (oceanic).

mantle: ultramafic

outer core: liquid iron and nickel

inner core: solid iron and nickel

Term
stratification
Definition
formation of layers of Earth
Term
how are igneous rocks formed
Definition
solidification of a melt
Term
two types of melt and descriptions
Definition

magma-melt in interior of Earth

lava-at surface

Term
melting temps of rock on surface
Definition
650-1110 degC
Term
how hot does it get in the different layers?
Definition

(state,behavior)

  • crust(solid,brittle): 0-500C
  • lithospheric mantle(s,b): 500-1280C
  • asthenospheric mantle(s,ductile): 1280-...C
  • inner core: up to 4300C
Term
how do rocks melt to form magma? (different melting)
Definition
  • heat-transfer melting (inc temp)
  • decompression melting (dec pressure, lower mp of rocks)
  • flux melting (change chem of rock.. ex. adding volatile elements like water or carbon dioxide dec mp of rocks)...Slide 15 .O {font-size:149%;}
    Volatiles like water and carbon dioxide get squeezed out of the subducting slab and seep into the overlying solid lithospheric mantle causing it to melt
Term
two types of igneous rocks and descriptions
Definition

Intrusive:

Slide 17 .O {font-size:149%;}

-igneous rock that solidified inside the Earth
-solidified from a magma
-coarse grained
Extrusive:
Slide 17 .O {font-size:149%;}
-igneous rock that solidified on the surface of the Earth
-solidified from a lava
-fine grained
 
 
 

 

Term
silicic igneous rock
Definition

66-76% silica

granite-intrusive

Term
intermediate igneous rock
Definition

52-66% silica

diorite-instrusive

Term
mafic igneous rock
Definition

45-52% silica

gabbro-instrusive

Term
ultramafic igneous rock
Definition

38-45% silica, ultrabasic (high in Mg/Fe)

peridotite (dominant in upper mantle)

Term
how to get magmas of different compositions?
Definition
  • partial melting (rocks and chocolate eggs)(describe the process in magma chamber)
  • fractional crystallization
  • assimilation
Term
intrusive rock settings
Definition
  • dike (ex.shiprock,nm , grand canyon
  • sill (ex.transantarctic mts)
  • laccolit-blister sill
  • pluton (large km ones=batholiths) (ex.yosemite, Torres del Paine NParks)
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