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 Image Number D116-1 |
Contour map of ARS's Walnut Gulch experimental watershed located near Tombstone, Arizona. The upper hillslope was tagged with praseodymium (blue), the middle area with gadolinium (green), and the lower area with samarium (purple); upper channels were tagged with lanthanum (yellow), and lower channels with neodymium (red).
Photo by Mark Nearing.
