Mineral Weathering

Mineral Weathering Lab Exercise

Here we will be working with weathering surface reduction measurements of marble headstones from cemeteries in Sydney, Australia and Wollongong, Australia, respectively. Marble is a metamorphic rock composed of recrystallized carbonate materials, commonly calcite and dolomite. Expand on your knowledge of carbonate mineralogy and it’s tendency to effervesce when dilute HCL acid is applied to complete the following mineral weathering lab exercise.

First, download the 2 comma-delimited (csv) data files, entitled sydney86.csv and wollon86.csv, and open them in MS Excel.

For this lab, you will expand your MS Excel spreadsheets and graphing skills even further! Use Google search and YouTube extensively for this exercise if you are unfamiliar with MS Excel and how to generate graphs, trendlines, and averages.

Next, familiarize yourself with MS Powerpoint. Again, if you need a refresher, lean on Google and YouTube.

Using MS Excel –
Copy and paste each dataset onto separate Excel tabs in the same file, label the tabs ‘Sydney’ and ‘Wollongong’, and save the Excel file with a .xls extension (Excel formatted file).
In each tab, generate a scatter plot (XY) graph of the respective data, and paste the graph in the tab to the right of the data. Apply appropriate labels to axes and a title for the graph.
Add a linear trendline for each graph, format the trendline to display the equation and R-squared value on the graph. Do NOT set an intercept.

Using Powerpoint –
Copy each Excel graph onto a separate slide. A simple copy and paste will do; do NOT paste the graph as a picture. Save the Powerpoint file. In Powerpoint, change the color of the data points, so that each plot is a different color.

Return to MS Excel –
Construct a graph show both datasets on one XY plot (for convenience you may choose to place this plot on a 3rd tab in Excel?). You will need to use different colors for each dataset. Add linear trendlines for each, as well as the respective equation and R-squared value. Make sure your trendlines are the same color as the respective data. Be sure to add a legend to this graph of 2 datasets.
Copy and paste this combined graph onto a third slide in the Powerpoint presentation file.

Return to Powerpoint –
On a fourth slide in the Powerpoint file, answer the following questions:
If y=mx+b (equation of a straight line), what is the slope of the Sydney surface reduction dataset? And the slope of the Wollongong?
Hence, what is the rate of weathering for each dataset? Remember your units!
Which linear trendline is a better fit to the respective data (perfect data fit = 1)? What does this tell us about our calculated weathering rates for the Sydney versus Wollongong data?
Does the Wollongong weathering rate (positive slope) make sense? Why or why not?
The city of Wollongong differs from Sydney in the fact that Wollongong industrialized more rapidly with a copper refinery in 1907 and a steel mill in 1928. How might this fact help explain the data?