Step-By-Step Instructions

The instructions for this exercise have 7 main parts. Click each part name to see the steps in that part.

The instructions for this chapter and the accompanying screenshots were developed using a Macintosh computer (OS X), Internet Explorer 5.2, and Excel 2004 for Mac. You will notice some differences if you are working on a computer that uses a Windows operating system.

Part 1 - Download Yellowstone data

Download and save the Yellowstone data

Part 2 - Download Crater Lake data

Download and save the Crater Lake data.

Part 3 - Import the data into Excel

Format and combine the Yellowstone and Crater Lake data into a single Excel file.

Part 4 - Prepare the data for graphing

Most files generated from GEOROC need a little post-download tweaking.

Part 5 - Decide which diagrams to plot

Which diagrams you will want to make will depend on the types of rocks you are investigating and the questions you want to answer.

Part 6 - Create a variation diagram

Use the Excel Chart Wizard to create a variation diagram that displays the data.

Part 7 - Analyze and interpret your results

Use the graphs to identify petrologic variation and geochemical trends. Identify similarities and differences between the two suites. Rule out or suggest possible petrologic processes to explain the data.