Silicified wood from around Old Faithful Geyser, Yellowstone National Park: Scanning Electron Microscopy (SEM)
Silicified wood samples were vacuum impregnated with epoxy, sectioned, and sputter coated with 10 nm Au/Pd at the U.S. Geological Survey, Menlo Park, CA. 
Samples were imaged in a Tescan VEGA3 Scanning Electron Microscope (SEM) equipped with an Oxford 150 mm2 X-MaxN large area energy dispersive spectrometer at the …