Creating Durov Diagrams

RockWorks | Utilities | HydroChem | Durov Diagram

This program reads concentration data from the Utilities datasheet and builds a Durov diagrams, which demonstrate the relationship between various ions within hydrochemical samples.  Total Dissolved Solids (TDS) values are depicted with proportionally scaled circles, similar to those in the Piper Diagram program.  Contours are also available for TDS data and relative sample density.

Concentrations entered in the source data file in units of milligrams per liter are converted to milli-equivalents per liter for display on the diagram.  (See Conversion Factors.)

The Durov Diagram is an alternative to the Piper Diagram.  In the two triangles, it plots the major ions as percentages of milliequivalents.  The totals of both the cations and anions are set to 100% and the data points in the two triangles are projected onto a square grid which lies perpendicular to the third axis in each triangle. 

Menu Options
Step-by-Step Summary

Menu Options

• Input Columns: The prompts along the left side of the window tell RockWorks which columns in the input datasheet contain what data.
  Click on an existing name to select a different name from the drop-down list.
  • Sample ID: If you have sample numbers listed for your sites, choose the column where these are listed.
  • Symbol:  Choose the column that lists specific symbols for the individual samples.
  • Na, K, Ca, Mg: Choose the columns that list these required cations.  The measurements must be listed in ppm or mg/l units.
  • Cl, HCO3, CO3, SO4: Choose the columns that list these required anions.  The measurements must be listed in ppm or mg/l units.
  • Cation A, B, C, D: If you are including any additional cations (see Additional Cations, below), choose their columns here.  
  • Anion A, B, C, D: If you are including any additional anions (see Additional Anions, below), choose their columns here.
    
    
• Additional Cations:  In the middle pane of the program window, expand this heading to turn on up to 4 additional (non-standard) cations to be included in the Durov Diagram's TDS (total dissolved solids) computations, if activated. Click in each check-box to turn an ion on or off.  Be sure that the ions are correctly identified in the input columns to the left. 
  
  • Conversion Factors: For each additional ion, you also need to declare a conversion factor to convert from ppm or mg/l to milli-equivalents.  See Conversion Factors for help. 
    ! This is important - RockWorks will not know this conversion factor automatically. You need to enter it manually.
    
    
• Additional Anions: Expand this heading to turn on up to 4 additional, non-standard, anions to be included in the Durov plot's TDS computations.  Click in each check-box to turn an ion on or off.  Be sure that the ions are correctly identified in the input columns to the left.
  
  • Conversion Factors: For each additional ion, you also need to declare a conversion factor to convert from ppm or mg/l to milli-equivalents.  See Conversion Factors for help.
    ! As above, this is important - RockWorks will not know this conversion factor automatically. You need to enter it manually.
    
    
• Titles:  Expand this item to specify text, if any, for the main and secondary diagram titles. You may enter up to 60 characters for each title. Expand these items to select their color.
  
• Border: Insert a check-mark here if you want the diagram border to be plotted. Expand this item to choose the style and color.
  
  
• TDS Circles: TDS (Total Dissolved Solids) circles are plotted as rings around each point in the square portion of the Durov diagram, and represent the combined total of all of the cations and anions in parts per million (or mg/l) for that sample (standard and any additional ions).
  
  • Scalar: If activated, you need to determine the scale at which the TDS circles will be plotted, using this setting. The number entered in this prompt will represent the number of ppm (or mg/l) units represented by the fixed-size Scale Bar which can be plotted to the left of the diagram, and the radius of the TDS circles.
    Here's an example for which the total dissolved solids for this single sample is 1,000 ppm.  The scalar is set to 2,000.  The radius of the circle is half the length of the fixed-size scale bar.
    

• Symbol Index: If activated, a small index listing sample ID's and their symbols will be included to the right of the Durov diagram.  If your samples have unique symbols, this is a handy way to identify samples without having to include labels in the diagram itself.
  
  
• Major Dividers, Minor Dividers: Insert a check in either/both of these items to create a reference background grid for both the triangular plots and the square plot. Expand these items to select their spacing (in percent) and line style and color. The percentage interval you select for the Major Dividers will also determine the axis labeling interval.  Major dividers are outlined in the first image in the left, and the Minor Dividers are outlined in red in the second image.

• Ternary Titles: Insert a check here to label the Cations and Anions axes.  An example Ternary title is circled in red directly below:
  

• Vertex Labels: Insert a check here to label the constituents for the vertices of the plot.  Some sample Vertex Labels are pointed next to blue arrows above.
  
• Axis Titles: Insert a check here to label the axes with the ions that they represent. You cannot change the text for these labels. Expand this item to select the title color.
  
• Axis Labels: Insert a check here to label the axis with the percentage intervals selected for the Major Dividers, above. Expand this item to select the label color.
  
• TDS Scalebar: If activated, the Total Dissolved Solids scalebar will be included with the diagram, at the scale declared under the TDS Scaler, above. Expand this item to select the scale bar color.

• Point Symbols: Insert a check here to have the symbols listed in the main datasheet plotted for each sample in the Durov diagram, using the color also listed in the datasheet. Expand this item to select the Size declared as percent of diagram width (default = 4.0).
  
  
• Point Labels: If activated, the sample's Point Symbols will be labeled with the sample ID. Like the symbols, above, you may click on the Size item to establish label size, in percent of diagram width.  You can also choose label color.
  
  
• Contour Data: Insert a check here to contour either the Sample Density or the TDS.  There are also a few options to select as far as contour lines, colored intervals, etc.
  • Contours Represent...
    • Sample Density: insert a check here to contour the number of occurrences of samples
    • TDS: check this option to contour the Z value which represents the total number of dissolved solids
  • Contour Lines
    • Intervals: Expand this to choose from a whole suite of contour options ranging from the scale, the line size and color, filtering in which you can skip low or high data values, etc.  See Contour Lines for additional information.
  • Colored Intervals: Expand this to choose from a suite of contour color-fill options.  See Color Intervals for more information.
  • Gridding Options: Expand this to select the density of the grid used for contouring
    • Smoothing: Expand to establish smoothing options (see general gridding options for additional information).

Step-by-Step Summary

1. Access the RockWorks Utilities program tab.
2. Create a new datasheet and enter/import your hydrochemistry data into the datasheet.
   Or, open one of the sample files and replace that data with your own. (In the Samples folder, an example file = "RockWorks17 Data\ Samples\Hydrochemistry_01.rwDat".)
3. Select the HydroChem | Durov Diagram menu option.
4. Enter the requested menu settings, described above.
5. Click the Process button to continue.
   
   The program will read the ion concentration information from the datasheet, convert the ppm or mg/l measurements to milli-equivalents per liter based on the conversion factors, normalize the measurements to plot the anions and cations in the trilinear plots, and project the samples over to the square plot. If total dissolved solids circles were requested, they will be computed and drawn around the sample points in the main diagram.
    
6. You can adjust any of the diagram options along the left and click the Process button to regenerate the plot.
   ! Each time you click the Process button, the existing display will be replaced. 
    
7. View / save / manipulate / print / export the diagram in the RockPlot2D window.  (More.)
   
   

Back to Hydrochemistry Menu Summary

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