|Figure 8-7. Botryoids of secondary aragonite (S) in pores (black "P"s) between layers of primary aragonite (red "P"s). Corroded primary aragonite (small blackarrows) is evidence that the large pores are secondary (ie.e., the result of dissolution of aragonite). The fact that the botryoids labelled as secondary hang downward is evidence that they are indeed secondary; primary botryoids almost always open upwards. The clearer and browner appeareance and finer crystal size of the secondary aragonite shown here are typical of secondary aragonite in this speleothem and another from Drotsky's Cave (Railsback et al., 1997). "a" indicates an artifact of thin section preparation. Another image in this atlas shows the same field of view in cross-polarized light.
Photomicrograph was taken in plane-polarized light; field of view is 0.9 mm wide. Drotsky's Cave, Botswana; Stalagmite BDS3; thin section B01; sample collected by Drs. George A. Brook and John Cooke.
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