Section #: 5.1 What Are Igneous Rocks?

Practice Test
      
  1.Peridotite and dunite have __________ compositions. SC.D.1.4.2  
  a.   mafic  
  b.   ultramafic  
  c.   felsic  
  d.   intermediate  
  Hint    
      
  2.Igneous rocks that cool on Earth's surface are called __________. SC.D.1.4.2  
  a.   lava  
  b.   molten  
  c.   intrusive  
  d.   extrusive  
  Hint    
      
  3.What process explains why a molten magma often is a mix of molten rock and crystals? SC.D.1.4.2  
  a.   Bowen's reaction series  
  b.   plate tectonics  
  c.   partial melting  
  d.   melting points  
  Hint    
      
  4.Which is not a compositional classification of a magma? SC.D.1.4.2  
  a.   andesitic  
  b.   basaltic  
  c.   phaneritic  
  d.   rhyolitic  
  Hint    
      
  5.What is the temperature change in Earth's crust called? SC.D.1.4.2  
  a.   radioactive decay  
  b.   geothermal gradient  
  c.   thermal energy  
  d.   hydrothermal gradient  
  Hint    
      
  6.Oceanic crust melts at __________ than continental crust. SC.D.1.4.2  
  a.   lower temperatures  
  b.   the same temperature  
  c.   higher temperatures  
  d.   higher pressures and lower temperatures  
  Hint    
      
  7.Extrusive rocks have fine-grained textures because __________. SC.D.1.4.2  
  a.   they cooled inside Earth's crust  
  b.   they cooled quickly  
  c.   they are derived from volcanoes  
  d.   they cooled slow  
  Hint    
      
  8.__________ explains the relationship between cooling magma and mineral formation. SC.D.1.4.2  
  a.   Geothermal gradients  
  b.   Bowen's reaction series  
  c.   Branches of crystallization  
  d.   Partial melting  
      
  9.What is the last mineral to form on the left branch of Bowen's reaction series? SC.D.1.4.2  
  a.   quartz  
  b.   olivine  
  c.   pyroxene  
  d.   feldspar  
      
  10.What is the source of heat inside Earth that melts rocks into magma? SC.D.1.4.2  
  a.   other molten rocks  
  b.   Earth's core is hotter for no reason.  
  c.   geothermal energy  
  d.   the decay of radioactive elements  
  Hint    
      
  11.What branch of Bowen's reaction series cools with a continuous change in composition? SC.D.1.4.2  
  a.   the feldspars  
  b.   the iron-magnesium groups  
  c.   the silica chains  
  d.   the carbonates  
      
  12.Granite is an example of __________ rock. SC.D.1.4.2  
  a.   a partially melted  
  b.   an intrusive igneous  
  c.   an extrusive igneous  
  d.   a volcanic ash  
      
  13.What extrusive igneous rock has a mafic composition and a glassy texture? SC.D.1.4.2  
  a.   obsidian  
  b.   basaltic glass  
  c.   gabbro  
  d.   diorite  
  Hint    
      
  14.How are igneous rocks formed? SC.D.1.4.2  
  a.   from increased pressures and temperatures  
  b.   from the cementation of mineral grains  
  c.   from the compaction of loose sediments  
  d.   from the crystallization of magma  
  Hint    

 
   
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