G119

Objectives Week 6

Igneous rock textures and compositions

 

1.   Differentiate between:

               a.  intrusive vs extrusive                                b.  plutonic vs volcanic

 

2.  Describe how cooling of a magma/lava can affect  crystal size within an igneous rock

 

3.   Understand the following terms:

               a.  vesicle                                                      e.  glassy

               b.  porphyritic                                               f.  pyroclastic

               c.  Phaneritic                                                 g.  amygdaloidal

               d.  aphanitic                                                  h.  pematitic

 

4.  Describe the classification of each composition of igneous rocks based on the relative amounts of  silica, iron and  magnesium,

               a.  ultramafic                                                c.  intermediate                       

               b.  mafic                                                       d.  silicic (felsic

 

 

5.  Know the following “pairs” of rocks with regards to their composition and be able to identify which are intrusive and which are extrusive.

                                                Intrusive                      Extrusive

                                                Granite                         Rhyolite

                                                Diorite                         Andesite

                                                Gabbro                        Basalt

                                                Peridotite                     Komatiite        

 

6.   Understand the sequence of crystallization in igneous rocks as described by the Bowen's Reaction Series and differentiate between the continuous and discontinuous series. 

 

7.   Be able to use Bowen’s reaction series to predict the composition of a magma from partial melting

                                                                                                                                                           

8.   Understand the basic concepts and processes of

               a.  crystal settling (gravity separation)/ filter pressing           

               c.  assimilation

               d.  magma mixing

 

9.  Know the following minerals/composition pairings:

 

              Felsic rocks:   Quartz and Microcline

              Intermediate rocks:   Often have hornblend and Biotite

              Mafic rocks:  Olivine and pyroxenes (augite and enstatite)