Summer Session II, 1996

Geology R1031/R5061 Midterm Examination Solution Key

  1. Oxide Molecular
    Weights    		 Minerals Rock, wt. %
    Olivine Clinopyroxene Anorthite Albite Orthoclase
    SiO2 60.09 34.89 51.73 43.20 68.74 64.76 53.64
    Al2O3 101.96 0.00 0.00 36.65 19.44 18.32 15.66
    MgO 40.3 23.40 8.67 0.00 0.00 0.00 4.94
    FeO 71.85 41.72 15.46 0.00 0.00 0.00 8.81
    CaO 56.08 0.00 24.14 20.16 0.00 0.00 12.08
    Na2O 61.98 0.00 0.00 0.00 11.82 0.00 2.84
    K2O 94.2 0.00 0.00 0.00 0.00 16.92 2.03
    Total, % 100.00 100.00 100.00 100.00 100.00 100.00

  2. Basalt

  3. Oxide
    wt. %
    SiO2 63.29
    Al2O3 11.66
    MgO 2.17
    FeO 3.87
    CaO 3.01
    Na2O 7.09
    K2O 5.08
    Total 100.00

  4. Dacite

  5. Oxide Density, kg/m3 Density, kg/m3
    Magma 1
    Magma 2
    SiO2 1205.03 1421.83
    Al2O3 422.37 314.55
    MgO 161.65 70.92
    FeO 454.10 199.24
    CaO 408.31 101.78
    Na2O 60.55 151.38
    K2O 41.31 103.28
    Total 2753.32 2362.99


  6. About 16.52 km

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Last updated: 8/21/96

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