Figure 8-12. Replacive calcite crystals (C) amidst aragonite (A) in a stalagmite from Botswana. Note preservation (and perhaps even enhancement) of layering in calcite at two black arrows. Red rectangle shows area of inset, in which red arrows point to inlcusions of aragonite within calcite. This field of view is between an area to right entirely of aragonite and an area to left almost entirely converted to calcite. Preliminary dating suggests that the aragonite is only a few hundred years old.
   Photomicrographs were taken in cross -polarized light. Field of view of main image is 2.3 mm wide; field of view of inset is 0.08 mm wide. Bone Cave, Botswana; Sample BC97-14; thin section BC 97-14-2. Sample collected by Dr. George A. Brook.
  Speleothem Image
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