Initial Publication Date: October 9, 2006

Part 4 - Collect and analyze volcanic rock compositions

For this final part of the exercise, you will download and examine silica compositions of volcanic rocks for each of the volcanoes you visited earlier. The chemical analyses are stored in the online North American Intrusive and Volcanic Rock Database (NAVDAT).

Volcanoes with single analyses

Chemical compositions are fairly uniform for volcanoes 1-2, 4, and 6-9. For this reason, analyses of single, representative samples are provided. For these volcanoes, simply find the silica (SiO2) content (in wt.%) for the corresponding analyzed sample and add this value to your data table. The NAVDAT sample data form also contains a classification chart near the bottom of the page. Use this chart to assign a rock name for the sample.

Volcanoes with multiple analyses

Chemical analyses are available for multiple samples for volcanoes 3, 5, and 10. For each of these volcanoes, follow the instructions to retrieve and examine the silica values for the available samples.

volcano 1

  • Go to the NAVDAT query page
  • SET "Latitude/Longitude" to the following parameters:
    • Northern Bound = 36.075
    • Southern Bound = 36.075
    • Western Bound = -117.8167
    • Eastern Bound = -117.8167
  • Click on "GO TO DATA"
  • Click on "Create HTML table

volcano 2

  • Go to the NAVDAT query page
  • SET "Latitude/Longitude" to the following parameters:
    • Northern Bound = 35.9281
    • Southern Bound = 35.9281
    • Western Bound = -117.7933
    • Eastern Bound = -117.7933
  • Click on "GO TO DATA"
  • Click on "Create HTML table

volcano 3

  • Go to the NAVDAT query page
  • SET "Sample Characteristics" to retrieve "Igneous" and "Volcanic" rocks only. Click "Apply".
  • SET "Latitude/Longitude" to the following parameters:
    • Northern Bound = 46.92
    • Southern Bound = 46.78
    • Western Bound = -121.88
    • Eastern Bound = -121.63
  • Click on "GO TO DATA"
  • Click on "Create Interactive Map, then "Click Here" to plot the data on an interactive map
  • Click on "Histogram"
  • Choose "SiO2" as the variable to plot on the histogram
  • Take note of the range and peak(s) of the resulting distribution

volcano 4

  • Go to the NAVDAT query page
  • SET "Latitude/Longitude" to the following parameters:
    • Northern Bound = 35.85
    • Southern Bound = 35.85
    • Western Bound = -119.0167
    • Eastern Bound = -119.0167
  • Click on "GO TO DATA"
  • Click on "Create HTML table

volcano 5

  • Go to the NAVDAT query page
  • SET "Sample Characteristics" to retrieve "Igneous" and "Volcanic" rocks only. Click "Apply".
  • SET "Latitude/Longitude" to the following parameters:
    • Northern Bound = 46.25
    • Southern Bound = 46.15
    • Western Bound = -122.25
    • Eastern Bound = -122.1
  • Click on "GO TO DATA"
  • Click on "Create Interactive Map, then "Click Here" to plot the data on an interactive map
  • Click on "Histogram"
  • Choose "SiO2" as the variable to plot on the histogram
  • Take note of the range and peak(s) of the resulting distribution

volcano 6

  • Go to the NAVDAT query page
  • SET "Latitude/Longitude" to the following parameters:
    • Northern Bound = 34.996
    • Southern Bound = 34.996
    • Western Bound = -108.08527
    • Eastern Bound = -108.08527
  • Click on "GO TO DATA"
  • Click on "Create HTML table

volcano 7

  • Go to the NAVDAT query page
  • SET "Latitude/Longitude" to the following parameters:
    • Northern Bound = 41.6828
    • Southern Bound = 41.6828
    • Western Bound = -121.5918
    • Eastern Bound = -121.5918
  • Click on "GO TO DATA"
  • Click on "Create HTML table

volcano 8

  • Go to the NAVDAT query page
  • SET "Latitude/Longitude" to the following parameters:
    • Northern Bound = 43.4259
    • Southern Bound = 43.4259
    • Western Bound = -120.7025
    • Eastern Bound = -120.7025
  • Click on "GO TO DATA"
  • Click on "Create HTML table

volcano 9

  • Go to the NAVDAT query page
  • SET "Latitude/Longitude" to the following parameters:
    • Northern Bound = 37.7667
    • Southern Bound = 37.7667
    • Western Bound = -119.0167
    • Eastern Bound = -119.0167
  • Click on "GO TO DATA"
  • Click on "Create HTML table

volcano 10

  • Go to the NAVDAT query page
  • SET "Sample Characteristics" to retrieve "Igneous" and "Volcanic" rocks only. Click "Apply".
  • SET "Volcanic Field" to "Crater Lake/Mount Mazama"
  • Click on "GO TO DATA"
  • Click on "Create Interactive Map, then "Click Here" to plot the data on an interactive map
  • Click on "Histogram"
  • Choose "SiO2" as the variable to plot on the histogram
  • Take note of the range and peak(s) of the resulting distribution